Header And Logo
|
#include "postgres.h"#include "access/sysattr.h"#include "catalog/pg_type.h"#include "commands/trigger.h"#include "foreign/fdwapi.h"#include "nodes/makefuncs.h"#include "nodes/nodeFuncs.h"#include "parser/analyze.h"#include "parser/parse_coerce.h"#include "parser/parsetree.h"#include "rewrite/rewriteDefine.h"#include "rewrite/rewriteHandler.h"#include "rewrite/rewriteManip.h"#include "utils/builtins.h"#include "utils/lsyscache.h"#include "utils/rel.h"
Go to the source code of this file.
Data Structures | |
| struct | rewrite_event |
Typedefs | |
| typedef struct rewrite_event | rewrite_event |
Functions | |
| static bool | acquireLocksOnSubLinks (Node *node, void *context) |
| static Query * | rewriteRuleAction (Query *parsetree, Query *rule_action, Node *rule_qual, int rt_index, CmdType event, bool *returning_flag) |
| static List * | adjustJoinTreeList (Query *parsetree, bool removert, int rt_index) |
| static void | rewriteTargetListIU (Query *parsetree, Relation target_relation, List **attrno_list) |
| static TargetEntry * | process_matched_tle (TargetEntry *src_tle, TargetEntry *prior_tle, const char *attrName) |
| static Node * | get_assignment_input (Node *node) |
| static void | rewriteValuesRTE (RangeTblEntry *rte, Relation target_relation, List *attrnos) |
| static void | rewriteTargetListUD (Query *parsetree, RangeTblEntry *target_rte, Relation target_relation) |
| static void | markQueryForLocking (Query *qry, Node *jtnode, LockClauseStrength strength, bool noWait, bool pushedDown) |
| static List * | matchLocks (CmdType event, RuleLock *rulelocks, int varno, Query *parsetree) |
| static Query * | fireRIRrules (Query *parsetree, List *activeRIRs, bool forUpdatePushedDown) |
| void | AcquireRewriteLocks (Query *parsetree, bool forUpdatePushedDown) |
| Node * | build_column_default (Relation rel, int attrno) |
| static bool | searchForDefault (RangeTblEntry *rte) |
| static Query * | ApplyRetrieveRule (Query *parsetree, RewriteRule *rule, int rt_index, bool relation_level, Relation relation, List *activeRIRs, bool forUpdatePushedDown) |
| static bool | fireRIRonSubLink (Node *node, List *activeRIRs) |
| static Query * | CopyAndAddInvertedQual (Query *parsetree, Node *rule_qual, int rt_index, CmdType event) |
| static List * | fireRules (Query *parsetree, int rt_index, CmdType event, List *locks, bool *instead_flag, bool *returning_flag, Query **qual_product) |
| static Query * | get_view_query (Relation view) |
| static bool | view_has_instead_trigger (Relation view, CmdType event) |
| static const char * | view_is_auto_updatable (Relation view) |
| bool | relation_is_updatable (Oid reloid, int req_events) |
| static Bitmapset * | adjust_view_column_set (Bitmapset *cols, List *targetlist) |
| static Query * | rewriteTargetView (Query *parsetree, Relation view) |
| static List * | RewriteQuery (Query *parsetree, List *rewrite_events) |
| List * | QueryRewrite (Query *parsetree) |
| typedef struct rewrite_event rewrite_event |
Definition at line 258 of file rewriteHandler.c.
References AcquireRewriteLocks(), expression_tree_walker(), IsA, NULL, and SubLink::subselect.
Referenced by AcquireRewriteLocks(), CopyAndAddInvertedQual(), and rewriteRuleAction().
{
if (node == NULL)
return false;
if (IsA(node, SubLink))
{
SubLink *sub = (SubLink *) node;
/* Do what we came for */
AcquireRewriteLocks((Query *) sub->subselect, false);
/* Fall through to process lefthand args of SubLink */
}
/*
* Do NOT recurse into Query nodes, because AcquireRewriteLocks already
* processed subselects of subselects for us.
*/
return expression_tree_walker(node, acquireLocksOnSubLinks, context);
}
Definition at line 103 of file rewriteHandler.c.
References acquireLocksOnSubLinks(), AcquireRewriteLocks(), Assert, Query::cteList, CommonTableExpr::ctequery, elog, ERROR, get_parse_rowmark(), get_rte_attribute_is_dropped(), Query::hasSubLinks, heap_close, heap_open(), INT4OID, InvalidOid, IsA, RangeTblEntry::joinaliasvars, lappend(), lfirst, makeNullConst(), NoLock, NULL, QTW_IGNORE_RC_SUBQUERIES, query_tree_walker(), RelationData::rd_rel, RangeTblEntry::relid, RangeTblEntry::relkind, Query::resultRelation, RowShareLock, rt_fetch, Query::rtable, RTE_JOIN, RTE_RELATION, RTE_SUBQUERY, RangeTblEntry::rtekind, RangeTblEntry::subquery, Var::varattno, Var::varlevelsup, and Var::varno.
Referenced by acquireLocksOnSubLinks(), AcquireRewriteLocks(), ApplyRetrieveRule(), get_query_def(), make_ruledef(), and rewriteRuleAction().
{
ListCell *l;
int rt_index;
/*
* First, process RTEs of the current query level.
*/
rt_index = 0;
foreach(l, parsetree->rtable)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
Relation rel;
LOCKMODE lockmode;
List *newaliasvars;
Index curinputvarno;
RangeTblEntry *curinputrte;
ListCell *ll;
++rt_index;
switch (rte->rtekind)
{
case RTE_RELATION:
/*
* Grab the appropriate lock type for the relation, and do not
* release it until end of transaction. This protects the
* rewriter and planner against schema changes mid-query.
*
* If the relation is the query's result relation, then we
* need RowExclusiveLock. Otherwise, check to see if the
* relation is accessed FOR [KEY] UPDATE/SHARE or not. We can't
* just grab AccessShareLock because then the executor would
* be trying to upgrade the lock, leading to possible
* deadlocks.
*/
if (rt_index == parsetree->resultRelation)
lockmode = RowExclusiveLock;
else if (forUpdatePushedDown ||
get_parse_rowmark(parsetree, rt_index) != NULL)
lockmode = RowShareLock;
else
lockmode = AccessShareLock;
rel = heap_open(rte->relid, lockmode);
/*
* While we have the relation open, update the RTE's relkind,
* just in case it changed since this rule was made.
*/
rte->relkind = rel->rd_rel->relkind;
heap_close(rel, NoLock);
break;
case RTE_JOIN:
/*
* Scan the join's alias var list to see if any columns have
* been dropped, and if so replace those Vars with NULL
* Consts.
*
* Since a join has only two inputs, we can expect to see
* multiple references to the same input RTE; optimize away
* multiple fetches.
*/
newaliasvars = NIL;
curinputvarno = 0;
curinputrte = NULL;
foreach(ll, rte->joinaliasvars)
{
Var *aliasvar = (Var *) lfirst(ll);
/*
* If the list item isn't a simple Var, then it must
* represent a merged column, ie a USING column, and so it
* couldn't possibly be dropped, since it's referenced in
* the join clause. (Conceivably it could also be a NULL
* constant already? But that's OK too.)
*/
if (IsA(aliasvar, Var))
{
/*
* The elements of an alias list have to refer to
* earlier RTEs of the same rtable, because that's the
* order the planner builds things in. So we already
* processed the referenced RTE, and so it's safe to
* use get_rte_attribute_is_dropped on it. (This might
* not hold after rewriting or planning, but it's OK
* to assume here.)
*/
Assert(aliasvar->varlevelsup == 0);
if (aliasvar->varno != curinputvarno)
{
curinputvarno = aliasvar->varno;
if (curinputvarno >= rt_index)
elog(ERROR, "unexpected varno %d in JOIN RTE %d",
curinputvarno, rt_index);
curinputrte = rt_fetch(curinputvarno,
parsetree->rtable);
}
if (get_rte_attribute_is_dropped(curinputrte,
aliasvar->varattno))
{
/*
* can't use vartype here, since that might be a
* now-dropped type OID, but it doesn't really
* matter what type the Const claims to be.
*/
aliasvar = (Var *) makeNullConst(INT4OID, -1, InvalidOid);
}
}
newaliasvars = lappend(newaliasvars, aliasvar);
}
rte->joinaliasvars = newaliasvars;
break;
case RTE_SUBQUERY:
/*
* The subquery RTE itself is all right, but we have to
* recurse to process the represented subquery.
*/
AcquireRewriteLocks(rte->subquery,
(forUpdatePushedDown ||
get_parse_rowmark(parsetree, rt_index) != NULL));
break;
default:
/* ignore other types of RTEs */
break;
}
}
/* Recurse into subqueries in WITH */
foreach(l, parsetree->cteList)
{
CommonTableExpr *cte = (CommonTableExpr *) lfirst(l);
AcquireRewriteLocks((Query *) cte->ctequery, false);
}
/*
* Recurse into sublink subqueries, too. But we already did the ones in
* the rtable and cteList.
*/
if (parsetree->hasSubLinks)
query_tree_walker(parsetree, acquireLocksOnSubLinks, NULL,
QTW_IGNORE_RC_SUBQUERIES);
}
Definition at line 2167 of file rewriteHandler.c.
References Assert, bms_add_member(), bms_copy(), bms_first_member(), bms_free(), elog, ERROR, TargetEntry::expr, get_tle_by_resno(), InvalidAttrNumber, IsA, lfirst, NULL, TargetEntry::resjunk, and Var::varattno.
Referenced by rewriteTargetView().
{
Bitmapset *result = NULL;
Bitmapset *tmpcols;
AttrNumber col;
tmpcols = bms_copy(cols);
while ((col = bms_first_member(tmpcols)) >= 0)
{
/* bit numbers are offset by FirstLowInvalidHeapAttributeNumber */
AttrNumber attno = col + FirstLowInvalidHeapAttributeNumber;
if (attno == InvalidAttrNumber)
{
/*
* There's a whole-row reference to the view. For permissions
* purposes, treat it as a reference to each column available from
* the view. (We should *not* convert this to a whole-row
* reference to the base relation, since the view may not touch
* all columns of the base relation.)
*/
ListCell *lc;
foreach(lc, targetlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(lc);
Var *var;
if (tle->resjunk)
continue;
var = (Var *) tle->expr;
Assert(IsA(var, Var));
result = bms_add_member(result,
var->varattno - FirstLowInvalidHeapAttributeNumber);
}
}
else
{
/*
* Views do not have system columns, so we do not expect to see
* any other system attnos here. If we do find one, the error
* case will apply.
*/
TargetEntry *tle = get_tle_by_resno(targetlist, attno);
if (tle != NULL && !tle->resjunk && IsA(tle->expr, Var))
{
Var *var = (Var *) tle->expr;
result = bms_add_member(result,
var->varattno - FirstLowInvalidHeapAttributeNumber);
}
else
elog(ERROR, "attribute number %d not found in view targetlist",
attno);
}
}
bms_free(tmpcols);
return result;
}
Definition at line 580 of file rewriteHandler.c.
References copyObject(), FromExpr::fromlist, IsA, Query::jointree, lfirst, list_delete_ptr(), and RangeTblRef::rtindex.
Referenced by rewriteRuleAction().
{
List *newjointree = copyObject(parsetree->jointree->fromlist);
ListCell *l;
if (removert)
{
foreach(l, newjointree)
{
RangeTblRef *rtr = lfirst(l);
if (IsA(rtr, RangeTblRef) &&
rtr->rtindex == rt_index)
{
newjointree = list_delete_ptr(newjointree, rtr);
/*
* foreach is safe because we exit loop after list_delete...
*/
break;
}
}
}
return newjointree;
}
| static Query* ApplyRetrieveRule | ( | Query * | parsetree, | |
| RewriteRule * | rule, | |||
| int | rt_index, | |||
| bool | relation_level, | |||
| Relation | relation, | |||
| List * | activeRIRs, | |||
| bool | forUpdatePushedDown | |||
| ) | [static] |
Definition at line 1296 of file rewriteHandler.c.
References AcquireRewriteLocks(), RewriteRule::actions, Assert, ChangeVarNodes(), RangeTblEntry::checkAsUser, CMD_DELETE, CMD_INSERT, CMD_UPDATE, Query::commandType, copyObject(), elog, ERROR, fireRIRrules(), get_parse_rowmark(), RangeTblEntry::inh, Query::jointree, lappend(), linitial, list_length(), markQueryForLocking(), RangeTblEntry::modifiedCols, RowMarkClause::noWait, NULL, PRS2_OLD_VARNO, RewriteRule::qual, RelationData::rd_id, RelationIsSecurityView, RangeTblEntry::relid, RangeTblEntry::requiredPerms, Query::resultRelation, Query::returningList, rt_fetch, Query::rtable, RangeTblEntry::rtekind, RangeTblEntry::security_barrier, RangeTblEntry::selectedCols, RowMarkClause::strength, and RangeTblEntry::subquery.
Referenced by fireRIRrules().
{
Query *rule_action;
RangeTblEntry *rte,
*subrte;
RowMarkClause *rc;
if (list_length(rule->actions) != 1)
elog(ERROR, "expected just one rule action");
if (rule->qual != NULL)
elog(ERROR, "cannot handle qualified ON SELECT rule");
if (!relation_level)
elog(ERROR, "cannot handle per-attribute ON SELECT rule");
if (rt_index == parsetree->resultRelation)
{
/*
* We have a view as the result relation of the query, and it wasn't
* rewritten by any rule. This case is supported if there is an
* INSTEAD OF trigger that will trap attempts to insert/update/delete
* view rows. The executor will check that; for the moment just plow
* ahead. We have two cases:
*
* For INSERT, we needn't do anything. The unmodified RTE will serve
* fine as the result relation.
*
* For UPDATE/DELETE, we need to expand the view so as to have source
* data for the operation. But we also need an unmodified RTE to
* serve as the target. So, copy the RTE and add the copy to the
* rangetable. Note that the copy does not get added to the jointree.
* Also note that there's a hack in fireRIRrules to avoid calling this
* function again when it arrives at the copied RTE.
*/
if (parsetree->commandType == CMD_INSERT)
return parsetree;
else if (parsetree->commandType == CMD_UPDATE ||
parsetree->commandType == CMD_DELETE)
{
RangeTblEntry *newrte;
rte = rt_fetch(rt_index, parsetree->rtable);
newrte = copyObject(rte);
parsetree->rtable = lappend(parsetree->rtable, newrte);
parsetree->resultRelation = list_length(parsetree->rtable);
/*
* There's no need to do permissions checks twice, so wipe out the
* permissions info for the original RTE (we prefer to keep the
* bits set on the result RTE).
*/
rte->requiredPerms = 0;
rte->checkAsUser = InvalidOid;
rte->selectedCols = NULL;
rte->modifiedCols = NULL;
/*
* For the most part, Vars referencing the view should remain as
* they are, meaning that they implicitly represent OLD values.
* But in the RETURNING list if any, we want such Vars to
* represent NEW values, so change them to reference the new RTE.
*
* Since ChangeVarNodes scribbles on the tree in-place, copy the
* RETURNING list first for safety.
*/
parsetree->returningList = copyObject(parsetree->returningList);
ChangeVarNodes((Node *) parsetree->returningList, rt_index,
parsetree->resultRelation, 0);
/* Now, continue with expanding the original view RTE */
}
else
elog(ERROR, "unrecognized commandType: %d",
(int) parsetree->commandType);
}
/*
* If FOR [KEY] UPDATE/SHARE of view, be sure we get right initial lock on the
* relations it references.
*/
rc = get_parse_rowmark(parsetree, rt_index);
forUpdatePushedDown |= (rc != NULL);
/*
* Make a modifiable copy of the view query, and acquire needed locks on
* the relations it mentions.
*/
rule_action = copyObject(linitial(rule->actions));
AcquireRewriteLocks(rule_action, forUpdatePushedDown);
/*
* Recursively expand any view references inside the view.
*/
rule_action = fireRIRrules(rule_action, activeRIRs, forUpdatePushedDown);
/*
* Now, plug the view query in as a subselect, replacing the relation's
* original RTE.
*/
rte = rt_fetch(rt_index, parsetree->rtable);
rte->rtekind = RTE_SUBQUERY;
rte->relid = InvalidOid;
rte->security_barrier = RelationIsSecurityView(relation);
rte->subquery = rule_action;
rte->inh = false; /* must not be set for a subquery */
/*
* We move the view's permission check data down to its rangetable. The
* checks will actually be done against the OLD entry therein.
*/
subrte = rt_fetch(PRS2_OLD_VARNO, rule_action->rtable);
Assert(subrte->relid == relation->rd_id);
subrte->requiredPerms = rte->requiredPerms;
subrte->checkAsUser = rte->checkAsUser;
subrte->selectedCols = rte->selectedCols;
subrte->modifiedCols = rte->modifiedCols;
rte->requiredPerms = 0; /* no permission check on subquery itself */
rte->checkAsUser = InvalidOid;
rte->selectedCols = NULL;
rte->modifiedCols = NULL;
/*
* If FOR [KEY] UPDATE/SHARE of view, mark all the contained tables as implicit
* FOR [KEY] UPDATE/SHARE, the same as the parser would have done if the view's
* subquery had been written out explicitly.
*
* Note: we don't consider forUpdatePushedDown here; such marks will be
* made by recursing from the upper level in markQueryForLocking.
*/
if (rc != NULL)
markQueryForLocking(rule_action, (Node *) rule_action->jointree,
rc->strength, rc->noWait, true);
return parsetree;
}
Definition at line 974 of file rewriteHandler.c.
References tupleDesc::attrs, COERCE_IMPLICIT_CAST, coerce_to_target_type(), COERCION_ASSIGNMENT, tupleDesc::constr, tupleConstr::defval, ereport, errcode(), errhint(), errmsg(), ERROR, exprType(), format_type_be(), get_typdefault(), NameStr, NULL, tupleConstr::num_defval, RelationData::rd_att, and stringToNode().
Referenced by ATExecAddColumn(), ATExecAlterColumnType(), BeginCopyFrom(), rewriteTargetListIU(), and rewriteValuesRTE().
{
TupleDesc rd_att = rel->rd_att;
Form_pg_attribute att_tup = rd_att->attrs[attrno - 1];
Oid atttype = att_tup->atttypid;
int32 atttypmod = att_tup->atttypmod;
Node *expr = NULL;
Oid exprtype;
/*
* Scan to see if relation has a default for this column.
*/
if (rd_att->constr && rd_att->constr->num_defval > 0)
{
AttrDefault *defval = rd_att->constr->defval;
int ndef = rd_att->constr->num_defval;
while (--ndef >= 0)
{
if (attrno == defval[ndef].adnum)
{
/*
* Found it, convert string representation to node tree.
*/
expr = stringToNode(defval[ndef].adbin);
break;
}
}
}
if (expr == NULL)
{
/*
* No per-column default, so look for a default for the type itself.
*/
expr = get_typdefault(atttype);
}
if (expr == NULL)
return NULL; /* No default anywhere */
/*
* Make sure the value is coerced to the target column type; this will
* generally be true already, but there seem to be some corner cases
* involving domain defaults where it might not be true. This should match
* the parser's processing of non-defaulted expressions --- see
* transformAssignedExpr().
*/
exprtype = exprType(expr);
expr = coerce_to_target_type(NULL, /* no UNKNOWN params here */
expr, exprtype,
atttype, atttypmod,
COERCION_ASSIGNMENT,
COERCE_IMPLICIT_CAST,
-1);
if (expr == NULL)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("column \"%s\" is of type %s"
" but default expression is of type %s",
NameStr(att_tup->attname),
format_type_be(atttype),
format_type_be(exprtype)),
errhint("You will need to rewrite or cast the expression.")));
return expr;
}
| static Query* CopyAndAddInvertedQual | ( | Query * | parsetree, | |
| Node * | rule_qual, | |||
| int | rt_index, | |||
| CmdType | event | |||
| ) | [static] |
Definition at line 1715 of file rewriteHandler.c.
References acquireLocksOnSubLinks(), AddInvertedQual(), ChangeVarNodes(), CMD_INSERT, CMD_UPDATE, copyObject(), Query::hasSubLinks, NULL, PRS2_NEW_VARNO, PRS2_OLD_VARNO, REPLACEVARS_CHANGE_VARNO, REPLACEVARS_SUBSTITUTE_NULL, ReplaceVarsFromTargetList(), rt_fetch, Query::rtable, and Query::targetList.
Referenced by fireRules().
{
/* Don't scribble on the passed qual (it's in the relcache!) */
Node *new_qual = (Node *) copyObject(rule_qual);
/*
* In case there are subqueries in the qual, acquire necessary locks and
* fix any deleted JOIN RTE entries. (This is somewhat redundant with
* rewriteRuleAction, but not entirely ... consider restructuring so that
* we only need to process the qual this way once.)
*/
(void) acquireLocksOnSubLinks(new_qual, NULL);
/* Fix references to OLD */
ChangeVarNodes(new_qual, PRS2_OLD_VARNO, rt_index, 0);
/* Fix references to NEW */
if (event == CMD_INSERT || event == CMD_UPDATE)
new_qual = ReplaceVarsFromTargetList(new_qual,
PRS2_NEW_VARNO,
0,
rt_fetch(rt_index,
parsetree->rtable),
parsetree->targetList,
(event == CMD_UPDATE) ?
REPLACEVARS_CHANGE_VARNO :
REPLACEVARS_SUBSTITUTE_NULL,
rt_index,
&parsetree->hasSubLinks);
/* And attach the fixed qual */
AddInvertedQual(parsetree, new_qual);
return parsetree;
}
Definition at line 1511 of file rewriteHandler.c.
References expression_tree_walker(), fireRIRrules(), IsA, NULL, and SubLink::subselect.
Referenced by fireRIRrules().
{
if (node == NULL)
return false;
if (IsA(node, SubLink))
{
SubLink *sub = (SubLink *) node;
/* Do what we came for */
sub->subselect = (Node *) fireRIRrules((Query *) sub->subselect,
activeRIRs, false);
/* Fall through to process lefthand args of SubLink */
}
/*
* Do NOT recurse into Query nodes, because fireRIRrules already processed
* subselects of subselects for us.
*/
return expression_tree_walker(node, fireRIRonSubLink,
(void *) activeRIRs);
}
| static Query * fireRIRrules | ( | Query * | parsetree, | |
| List * | activeRIRs, | |||
| bool | forUpdatePushedDown | |||
| ) | [static] |
Definition at line 1539 of file rewriteHandler.c.
References ApplyRetrieveRule(), attribute_used(), RewriteRule::attrno, CMD_SELECT, Query::cteList, CommonTableExpr::ctequery, ereport, errcode(), errmsg(), ERROR, RewriteRule::event, fireRIRonSubLink(), get_parse_rowmark(), Query::hasSubLinks, heap_close, heap_open(), i, lappend(), lcons_oid(), lfirst, list_delete_first(), list_length(), list_member_oid(), NIL, NoLock, NULL, RuleLock::numLocks, QTW_IGNORE_RC_SUBQUERIES, query_tree_walker(), rangeTableEntry_used(), RelationData::rd_rules, RelationGetRelationName, RelationGetRelid, RangeTblEntry::relid, RangeTblEntry::relkind, RELKIND_MATVIEW, Query::resultRelation, rt_fetch, Query::rtable, RTE_RELATION, RTE_SUBQUERY, RangeTblEntry::rtekind, RuleLock::rules, rules, and RangeTblEntry::subquery.
Referenced by ApplyRetrieveRule(), fireRIRonSubLink(), and QueryRewrite().
{
int origResultRelation = parsetree->resultRelation;
int rt_index;
ListCell *lc;
/*
* don't try to convert this into a foreach loop, because rtable list can
* get changed each time through...
*/
rt_index = 0;
while (rt_index < list_length(parsetree->rtable))
{
RangeTblEntry *rte;
Relation rel;
List *locks;
RuleLock *rules;
RewriteRule *rule;
int i;
++rt_index;
rte = rt_fetch(rt_index, parsetree->rtable);
/*
* A subquery RTE can't have associated rules, so there's nothing to
* do to this level of the query, but we must recurse into the
* subquery to expand any rule references in it.
*/
if (rte->rtekind == RTE_SUBQUERY)
{
rte->subquery = fireRIRrules(rte->subquery, activeRIRs,
(forUpdatePushedDown ||
get_parse_rowmark(parsetree, rt_index) != NULL));
continue;
}
/*
* Joins and other non-relation RTEs can be ignored completely.
*/
if (rte->rtekind != RTE_RELATION)
continue;
/*
* Always ignore RIR rules for materialized views referenced in
* queries. (This does not prevent refreshing MVs, since they aren't
* referenced in their own query definitions.)
*
* Note: in the future we might want to allow MVs to be conditionally
* expanded as if they were regular views, if they are not scannable.
* In that case this test would need to be postponed till after we've
* opened the rel, so that we could check its state.
*/
if (rte->relkind == RELKIND_MATVIEW)
continue;
/*
* If the table is not referenced in the query, then we ignore it.
* This prevents infinite expansion loop due to new rtable entries
* inserted by expansion of a rule. A table is referenced if it is
* part of the join set (a source table), or is referenced by any Var
* nodes, or is the result table.
*/
if (rt_index != parsetree->resultRelation &&
!rangeTableEntry_used((Node *) parsetree, rt_index, 0))
continue;
/*
* Also, if this is a new result relation introduced by
* ApplyRetrieveRule, we don't want to do anything more with it.
*/
if (rt_index == parsetree->resultRelation &&
rt_index != origResultRelation)
continue;
/*
* We can use NoLock here since either the parser or
* AcquireRewriteLocks should have locked the rel already.
*/
rel = heap_open(rte->relid, NoLock);
/*
* Collect the RIR rules that we must apply
*/
rules = rel->rd_rules;
if (rules == NULL)
{
heap_close(rel, NoLock);
continue;
}
locks = NIL;
for (i = 0; i < rules->numLocks; i++)
{
rule = rules->rules[i];
if (rule->event != CMD_SELECT)
continue;
if (rule->attrno > 0)
{
/* per-attr rule; do we need it? */
if (!attribute_used((Node *) parsetree, rt_index,
rule->attrno, 0))
continue;
}
locks = lappend(locks, rule);
}
/*
* If we found any, apply them --- but first check for recursion!
*/
if (locks != NIL)
{
ListCell *l;
if (list_member_oid(activeRIRs, RelationGetRelid(rel)))
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("infinite recursion detected in rules for relation \"%s\"",
RelationGetRelationName(rel))));
activeRIRs = lcons_oid(RelationGetRelid(rel), activeRIRs);
foreach(l, locks)
{
rule = lfirst(l);
parsetree = ApplyRetrieveRule(parsetree,
rule,
rt_index,
rule->attrno == -1,
rel,
activeRIRs,
forUpdatePushedDown);
}
activeRIRs = list_delete_first(activeRIRs);
}
heap_close(rel, NoLock);
}
/* Recurse into subqueries in WITH */
foreach(lc, parsetree->cteList)
{
CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
cte->ctequery = (Node *)
fireRIRrules((Query *) cte->ctequery, activeRIRs, false);
}
/*
* Recurse into sublink subqueries, too. But we already did the ones in
* the rtable and cteList.
*/
if (parsetree->hasSubLinks)
query_tree_walker(parsetree, fireRIRonSubLink, (void *) activeRIRs,
QTW_IGNORE_RC_SUBQUERIES);
return parsetree;
}
| static List* fireRules | ( | Query * | parsetree, | |
| int | rt_index, | |||
| CmdType | event, | |||
| List * | locks, | |||
| bool * | instead_flag, | |||
| bool * | returning_flag, | |||
| Query ** | qual_product | |||
| ) | [static] |
Definition at line 1782 of file rewriteHandler.c.
References RewriteRule::actions, Query::canSetTag, CMD_NOTHING, Query::commandType, CopyAndAddInvertedQual(), copyObject(), RewriteRule::isInstead, lappend(), lfirst, NULL, QSRC_QUAL_INSTEAD_RULE, RewriteRule::qual, Query::querySource, and rewriteRuleAction().
Referenced by RewriteQuery().
{
List *results = NIL;
ListCell *l;
foreach(l, locks)
{
RewriteRule *rule_lock = (RewriteRule *) lfirst(l);
Node *event_qual = rule_lock->qual;
List *actions = rule_lock->actions;
QuerySource qsrc;
ListCell *r;
/* Determine correct QuerySource value for actions */
if (rule_lock->isInstead)
{
if (event_qual != NULL)
qsrc = QSRC_QUAL_INSTEAD_RULE;
else
{
qsrc = QSRC_INSTEAD_RULE;
*instead_flag = true; /* report unqualified INSTEAD */
}
}
else
qsrc = QSRC_NON_INSTEAD_RULE;
if (qsrc == QSRC_QUAL_INSTEAD_RULE)
{
/*
* If there are INSTEAD rules with qualifications, the original
* query is still performed. But all the negated rule
* qualifications of the INSTEAD rules are added so it does its
* actions only in cases where the rule quals of all INSTEAD rules
* are false. Think of it as the default action in a case. We save
* this in *qual_product so RewriteQuery() can add it to the query
* list after we mangled it up enough.
*
* If we have already found an unqualified INSTEAD rule, then
* *qual_product won't be used, so don't bother building it.
*/
if (!*instead_flag)
{
if (*qual_product == NULL)
*qual_product = copyObject(parsetree);
*qual_product = CopyAndAddInvertedQual(*qual_product,
event_qual,
rt_index,
event);
}
}
/* Now process the rule's actions and add them to the result list */
foreach(r, actions)
{
Query *rule_action = lfirst(r);
if (rule_action->commandType == CMD_NOTHING)
continue;
rule_action = rewriteRuleAction(parsetree, rule_action,
event_qual, rt_index, event,
returning_flag);
rule_action->querySource = qsrc;
rule_action->canSetTag = false; /* might change later */
results = lappend(results, rule_action);
}
}
return results;
}
Definition at line 947 of file rewriteHandler.c.
References FieldStore::arg, IsA, NULL, ArrayRef::refassgnexpr, and ArrayRef::refexpr.
Referenced by process_matched_tle().
{
if (node == NULL)
return NULL;
if (IsA(node, FieldStore))
{
FieldStore *fstore = (FieldStore *) node;
return (Node *) fstore->arg;
}
else if (IsA(node, ArrayRef))
{
ArrayRef *aref = (ArrayRef *) node;
if (aref->refassgnexpr == NULL)
return NULL;
return (Node *) aref->refexpr;
}
return NULL;
}
Definition at line 1870 of file rewriteHandler.c.
References RewriteRule::actions, Assert, CMD_SELECT, elog, ERROR, RewriteRule::event, i, linitial, list_length(), RuleLock::numLocks, RelationData::rd_rel, RelationData::rd_rules, RELKIND_VIEW, and RuleLock::rules.
Referenced by relation_is_updatable(), rewriteTargetView(), and view_is_auto_updatable().
{
int i;
Assert(view->rd_rel->relkind == RELKIND_VIEW);
for (i = 0; i < view->rd_rules->numLocks; i++)
{
RewriteRule *rule = view->rd_rules->rules[i];
if (rule->event == CMD_SELECT)
{
/* A _RETURN rule should have only one action */
if (list_length(rule->actions) != 1)
elog(ERROR, "invalid _RETURN rule action specification");
return (Query *) linitial(rule->actions);
}
}
elog(ERROR, "failed to find _RETURN rule for view");
return NULL; /* keep compiler quiet */
}
| static void markQueryForLocking | ( | Query * | qry, | |
| Node * | jtnode, | |||
| LockClauseStrength | strength, | |||
| bool | noWait, | |||
| bool | pushedDown | |||
| ) | [static] |
Definition at line 1452 of file rewriteHandler.c.
References applyLockingClause(), elog, ERROR, FromExpr::fromlist, IsA, Query::jointree, JoinExpr::larg, lfirst, nodeTag, NULL, JoinExpr::rarg, RangeTblEntry::requiredPerms, rt_fetch, Query::rtable, RTE_RELATION, RTE_SUBQUERY, RangeTblEntry::rtekind, and RangeTblEntry::subquery.
Referenced by ApplyRetrieveRule().
{
if (jtnode == NULL)
return;
if (IsA(jtnode, RangeTblRef))
{
int rti = ((RangeTblRef *) jtnode)->rtindex;
RangeTblEntry *rte = rt_fetch(rti, qry->rtable);
if (rte->rtekind == RTE_RELATION)
{
applyLockingClause(qry, rti, strength, noWait, pushedDown);
rte->requiredPerms |= ACL_SELECT_FOR_UPDATE;
}
else if (rte->rtekind == RTE_SUBQUERY)
{
applyLockingClause(qry, rti, strength, noWait, pushedDown);
/* FOR UPDATE/SHARE of subquery is propagated to subquery's rels */
markQueryForLocking(rte->subquery, (Node *) rte->subquery->jointree,
strength, noWait, true);
}
/* other RTE types are unaffected by FOR UPDATE */
}
else if (IsA(jtnode, FromExpr))
{
FromExpr *f = (FromExpr *) jtnode;
ListCell *l;
foreach(l, f->fromlist)
markQueryForLocking(qry, lfirst(l), strength, noWait, pushedDown);
}
else if (IsA(jtnode, JoinExpr))
{
JoinExpr *j = (JoinExpr *) jtnode;
markQueryForLocking(qry, j->larg, strength, noWait, pushedDown);
markQueryForLocking(qry, j->rarg, strength, noWait, pushedDown);
}
else
elog(ERROR, "unrecognized node type: %d",
(int) nodeTag(jtnode));
}
| static List * matchLocks | ( | CmdType | event, | |
| RuleLock * | rulelocks, | |||
| int | varno, | |||
| Query * | parsetree | |||
| ) | [static] |
Definition at line 1231 of file rewriteHandler.c.
References attribute_used(), RewriteRule::attrno, CMD_SELECT, Query::commandType, RewriteRule::enabled, RewriteRule::event, i, lappend(), NULL, RuleLock::numLocks, rangeTableEntry_used(), Query::resultRelation, RULE_DISABLED, RULE_FIRES_ON_ORIGIN, RULE_FIRES_ON_REPLICA, RuleLock::rules, SESSION_REPLICATION_ROLE_REPLICA, and SessionReplicationRole.
Referenced by RewriteQuery().
{
List *matching_locks = NIL;
int nlocks;
int i;
if (rulelocks == NULL)
return NIL;
if (parsetree->commandType != CMD_SELECT)
{
if (parsetree->resultRelation != varno)
return NIL;
}
nlocks = rulelocks->numLocks;
for (i = 0; i < nlocks; i++)
{
RewriteRule *oneLock = rulelocks->rules[i];
/*
* Suppress ON INSERT/UPDATE/DELETE rules that are disabled or
* configured to not fire during the current sessions replication
* role. ON SELECT rules will always be applied in order to keep views
* working even in LOCAL or REPLICA role.
*/
if (oneLock->event != CMD_SELECT)
{
if (SessionReplicationRole == SESSION_REPLICATION_ROLE_REPLICA)
{
if (oneLock->enabled == RULE_FIRES_ON_ORIGIN ||
oneLock->enabled == RULE_DISABLED)
continue;
}
else /* ORIGIN or LOCAL ROLE */
{
if (oneLock->enabled == RULE_FIRES_ON_REPLICA ||
oneLock->enabled == RULE_DISABLED)
continue;
}
}
if (oneLock->event == event)
{
if (parsetree->commandType != CMD_SELECT ||
(oneLock->attrno == -1 ?
rangeTableEntry_used((Node *) parsetree, varno, 0) :
attribute_used((Node *) parsetree,
varno, oneLock->attrno, 0)))
matching_locks = lappend(matching_locks, oneLock);
}
}
return matching_locks;
}
| static TargetEntry * process_matched_tle | ( | TargetEntry * | src_tle, | |
| TargetEntry * | prior_tle, | |||
| const char * | attrName | |||
| ) | [static] |
Definition at line 825 of file rewriteHandler.c.
References FieldStore::arg, elog, equal(), ereport, errcode(), errmsg(), ERROR, TargetEntry::expr, exprType(), FieldStore::fieldnums, flatCopyTargetEntry(), get_assignment_input(), IsA, list_concat(), list_copy(), makeNode, FieldStore::newvals, NULL, and ArrayRef::refexpr.
Referenced by rewriteTargetListIU().
{
TargetEntry *result;
Node *src_expr;
Node *prior_expr;
Node *src_input;
Node *prior_input;
Node *priorbottom;
Node *newexpr;
if (prior_tle == NULL)
{
/*
* Normal case where this is the first assignment to the attribute.
*/
return src_tle;
}
/*----------
* Multiple assignments to same attribute. Allow only if all are
* FieldStore or ArrayRef assignment operations. This is a bit
* tricky because what we may actually be looking at is a nest of
* such nodes; consider
* UPDATE tab SET col.fld1.subfld1 = x, col.fld2.subfld2 = y
* The two expressions produced by the parser will look like
* FieldStore(col, fld1, FieldStore(placeholder, subfld1, x))
* FieldStore(col, fld2, FieldStore(placeholder, subfld2, x))
* However, we can ignore the substructure and just consider the top
* FieldStore or ArrayRef from each assignment, because it works to
* combine these as
* FieldStore(FieldStore(col, fld1,
* FieldStore(placeholder, subfld1, x)),
* fld2, FieldStore(placeholder, subfld2, x))
* Note the leftmost expression goes on the inside so that the
* assignments appear to occur left-to-right.
*
* For FieldStore, instead of nesting we can generate a single
* FieldStore with multiple target fields. We must nest when
* ArrayRefs are involved though.
*----------
*/
src_expr = (Node *) src_tle->expr;
prior_expr = (Node *) prior_tle->expr;
src_input = get_assignment_input(src_expr);
prior_input = get_assignment_input(prior_expr);
if (src_input == NULL ||
prior_input == NULL ||
exprType(src_expr) != exprType(prior_expr))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("multiple assignments to same column \"%s\"",
attrName)));
/*
* Prior TLE could be a nest of assignments if we do this more than once.
*/
priorbottom = prior_input;
for (;;)
{
Node *newbottom = get_assignment_input(priorbottom);
if (newbottom == NULL)
break; /* found the original Var reference */
priorbottom = newbottom;
}
if (!equal(priorbottom, src_input))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("multiple assignments to same column \"%s\"",
attrName)));
/*
* Looks OK to nest 'em.
*/
if (IsA(src_expr, FieldStore))
{
FieldStore *fstore = makeNode(FieldStore);
if (IsA(prior_expr, FieldStore))
{
/* combine the two */
memcpy(fstore, prior_expr, sizeof(FieldStore));
fstore->newvals =
list_concat(list_copy(((FieldStore *) prior_expr)->newvals),
list_copy(((FieldStore *) src_expr)->newvals));
fstore->fieldnums =
list_concat(list_copy(((FieldStore *) prior_expr)->fieldnums),
list_copy(((FieldStore *) src_expr)->fieldnums));
}
else
{
/* general case, just nest 'em */
memcpy(fstore, src_expr, sizeof(FieldStore));
fstore->arg = (Expr *) prior_expr;
}
newexpr = (Node *) fstore;
}
else if (IsA(src_expr, ArrayRef))
{
ArrayRef *aref = makeNode(ArrayRef);
memcpy(aref, src_expr, sizeof(ArrayRef));
aref->refexpr = (Expr *) prior_expr;
newexpr = (Node *) aref;
}
else
{
elog(ERROR, "cannot happen");
newexpr = NULL;
}
result = flatCopyTargetEntry(src_tle);
result->expr = (Expr *) newexpr;
return result;
}
Definition at line 2854 of file rewriteHandler.c.
References Assert, Query::canSetTag, Query::commandType, fireRIRrules(), lappend(), lfirst, NIL, NULL, QSRC_INSTEAD_RULE, QSRC_ORIGINAL, QSRC_QUAL_INSTEAD_RULE, Query::queryId, Query::querySource, and RewriteQuery().
Referenced by ExecCreateTableAs(), ExplainOneUtility(), ExplainQuery(), pg_rewrite_query(), PrepareQuery(), and refresh_matview_datafill().
{
uint32 input_query_id = parsetree->queryId;
List *querylist;
List *results;
ListCell *l;
CmdType origCmdType;
bool foundOriginalQuery;
Query *lastInstead;
/*
* This function is only applied to top-level original queries
*/
Assert(parsetree->querySource == QSRC_ORIGINAL);
Assert(parsetree->canSetTag);
/*
* Step 1
*
* Apply all non-SELECT rules possibly getting 0 or many queries
*/
querylist = RewriteQuery(parsetree, NIL);
/*
* Step 2
*
* Apply all the RIR rules on each query
*
* This is also a handy place to mark each query with the original queryId
*/
results = NIL;
foreach(l, querylist)
{
Query *query = (Query *) lfirst(l);
query = fireRIRrules(query, NIL, false);
query->queryId = input_query_id;
results = lappend(results, query);
}
/*
* Step 3
*
* Determine which, if any, of the resulting queries is supposed to set
* the command-result tag; and update the canSetTag fields accordingly.
*
* If the original query is still in the list, it sets the command tag.
* Otherwise, the last INSTEAD query of the same kind as the original is
* allowed to set the tag. (Note these rules can leave us with no query
* setting the tag. The tcop code has to cope with this by setting up a
* default tag based on the original un-rewritten query.)
*
* The Asserts verify that at most one query in the result list is marked
* canSetTag. If we aren't checking asserts, we can fall out of the loop
* as soon as we find the original query.
*/
origCmdType = parsetree->commandType;
foundOriginalQuery = false;
lastInstead = NULL;
foreach(l, results)
{
Query *query = (Query *) lfirst(l);
if (query->querySource == QSRC_ORIGINAL)
{
Assert(query->canSetTag);
Assert(!foundOriginalQuery);
foundOriginalQuery = true;
#ifndef USE_ASSERT_CHECKING
break;
#endif
}
else
{
Assert(!query->canSetTag);
if (query->commandType == origCmdType &&
(query->querySource == QSRC_INSTEAD_RULE ||
query->querySource == QSRC_QUAL_INSTEAD_RULE))
lastInstead = query;
}
}
if (!foundOriginalQuery && lastInstead != NULL)
lastInstead->canSetTag = true;
return results;
}
Definition at line 2083 of file rewriteHandler.c.
References AccessShareLock, RewriteRule::event, FromExpr::fromlist, get_view_query(), i, RewriteRule::isInstead, Query::jointree, linitial, NULL, RuleLock::numLocks, RewriteRule::qual, RelationData::rd_rel, RelationData::rd_rules, relation_close(), relation_is_updatable(), RangeTblEntry::relid, RangeTblEntry::relkind, RELKIND_RELATION, RELKIND_VIEW, rt_fetch, Query::rtable, RangeTblRef::rtindex, RuleLock::rules, try_relation_open(), and view_is_auto_updatable().
Referenced by pg_view_is_insertable(), pg_view_is_updatable(), and relation_is_updatable().
{
Relation rel;
RuleLock *rulelocks;
rel = try_relation_open(reloid, AccessShareLock);
/*
* If the relation doesn't exist, say "false" rather than throwing an
* error. This is helpful since scanning an information_schema view
* under MVCC rules can result in referencing rels that were just
* deleted according to a SnapshotNow probe.
*/
if (rel == NULL)
return false;
/* Look for unconditional DO INSTEAD rules, and note supported events */
rulelocks = rel->rd_rules;
if (rulelocks != NULL)
{
int events = 0;
int i;
for (i = 0; i < rulelocks->numLocks; i++)
{
if (rulelocks->rules[i]->isInstead &&
rulelocks->rules[i]->qual == NULL)
{
events |= 1 << rulelocks->rules[i]->event;
}
}
/* If we have all rules needed, say "yes" */
if ((events & req_events) == req_events)
{
relation_close(rel, AccessShareLock);
return true;
}
}
/* Check if this is an automatically updatable view */
if (rel->rd_rel->relkind == RELKIND_VIEW &&
view_is_auto_updatable(rel) == NULL)
{
Query *viewquery;
RangeTblRef *rtr;
RangeTblEntry *base_rte;
Oid baseoid;
/* The base relation must also be updatable */
viewquery = get_view_query(rel);
rtr = (RangeTblRef *) linitial(viewquery->jointree->fromlist);
base_rte = rt_fetch(rtr->rtindex, viewquery->rtable);
if (base_rte->relkind == RELKIND_RELATION)
{
/* Tables are always updatable */
relation_close(rel, AccessShareLock);
return true;
}
else
{
/* Do a recursive check for any other kind of base relation */
baseoid = base_rte->relid;
relation_close(rel, AccessShareLock);
return relation_is_updatable(baseoid, req_events);
}
}
/* If we reach here, the relation is not updatable */
relation_close(rel, AccessShareLock);
return false;
}
Definition at line 2498 of file rewriteHandler.c.
References Assert, Query::canSetTag, CMD_DELETE, CMD_INSERT, CMD_SELECT, CMD_UPDATE, CMD_UTILITY, Query::commandType, Query::cteList, CommonTableExpr::ctequery, elog, ereport, errcode(), errhint(), errmsg(), ERROR, rewrite_event::event, fireRules(), FromExpr::fromlist, heap_close, heap_open(), IsA, Query::jointree, lappend(), lcons(), lfirst, linitial, list_concat(), list_delete_first(), list_length(), matchLocks(), NIL, NoLock, NULL, palloc(), QSRC_NON_INSTEAD_RULE, QSRC_QUAL_INSTEAD_RULE, Query::querySource, RelationData::rd_rel, RelationData::rd_rules, rewrite_event::relation, RelationGetRelationName, RelationGetRelid, RangeTblEntry::relid, RELKIND_VIEW, Query::resultRelation, Query::returningList, rewriteTargetListIU(), rewriteTargetListUD(), rewriteTargetView(), rewriteValuesRTE(), rt_fetch, Query::rtable, RTE_RELATION, RTE_VALUES, RangeTblEntry::rtekind, RangeTblRef::rtindex, and view_has_instead_trigger().
Referenced by QueryRewrite().
{
CmdType event = parsetree->commandType;
bool instead = false;
bool returning = false;
Query *qual_product = NULL;
List *rewritten = NIL;
ListCell *lc1;
/*
* First, recursively process any insert/update/delete statements in WITH
* clauses. (We have to do this first because the WITH clauses may get
* copied into rule actions below.)
*/
foreach(lc1, parsetree->cteList)
{
CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc1);
Query *ctequery = (Query *) cte->ctequery;
List *newstuff;
Assert(IsA(ctequery, Query));
if (ctequery->commandType == CMD_SELECT)
continue;
newstuff = RewriteQuery(ctequery, rewrite_events);
/*
* Currently we can only handle unconditional, single-statement DO
* INSTEAD rules correctly; we have to get exactly one Query out of
* the rewrite operation to stuff back into the CTE node.
*/
if (list_length(newstuff) == 1)
{
/* Push the single Query back into the CTE node */
ctequery = (Query *) linitial(newstuff);
Assert(IsA(ctequery, Query));
/* WITH queries should never be canSetTag */
Assert(!ctequery->canSetTag);
cte->ctequery = (Node *) ctequery;
}
else if (newstuff == NIL)
{
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("DO INSTEAD NOTHING rules are not supported for data-modifying statements in WITH")));
}
else
{
ListCell *lc2;
/* examine queries to determine which error message to issue */
foreach(lc2, newstuff)
{
Query *q = (Query *) lfirst(lc2);
if (q->querySource == QSRC_QUAL_INSTEAD_RULE)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("conditional DO INSTEAD rules are not supported for data-modifying statements in WITH")));
if (q->querySource == QSRC_NON_INSTEAD_RULE)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("DO ALSO rules are not supported for data-modifying statements in WITH")));
}
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("multi-statement DO INSTEAD rules are not supported for data-modifying statements in WITH")));
}
}
/*
* If the statement is an insert, update, or delete, adjust its targetlist
* as needed, and then fire INSERT/UPDATE/DELETE rules on it.
*
* SELECT rules are handled later when we have all the queries that should
* get executed. Also, utilities aren't rewritten at all (do we still
* need that check?)
*/
if (event != CMD_SELECT && event != CMD_UTILITY)
{
int result_relation;
RangeTblEntry *rt_entry;
Relation rt_entry_relation;
List *locks;
List *product_queries;
result_relation = parsetree->resultRelation;
Assert(result_relation != 0);
rt_entry = rt_fetch(result_relation, parsetree->rtable);
Assert(rt_entry->rtekind == RTE_RELATION);
/*
* We can use NoLock here since either the parser or
* AcquireRewriteLocks should have locked the rel already.
*/
rt_entry_relation = heap_open(rt_entry->relid, NoLock);
/*
* Rewrite the targetlist as needed for the command type.
*/
if (event == CMD_INSERT)
{
RangeTblEntry *values_rte = NULL;
/*
* If it's an INSERT ... VALUES (...), (...), ... there will be a
* single RTE for the VALUES targetlists.
*/
if (list_length(parsetree->jointree->fromlist) == 1)
{
RangeTblRef *rtr = (RangeTblRef *) linitial(parsetree->jointree->fromlist);
if (IsA(rtr, RangeTblRef))
{
RangeTblEntry *rte = rt_fetch(rtr->rtindex,
parsetree->rtable);
if (rte->rtekind == RTE_VALUES)
values_rte = rte;
}
}
if (values_rte)
{
List *attrnos;
/* Process the main targetlist ... */
rewriteTargetListIU(parsetree, rt_entry_relation, &attrnos);
/* ... and the VALUES expression lists */
rewriteValuesRTE(values_rte, rt_entry_relation, attrnos);
}
else
{
/* Process just the main targetlist */
rewriteTargetListIU(parsetree, rt_entry_relation, NULL);
}
}
else if (event == CMD_UPDATE)
{
rewriteTargetListIU(parsetree, rt_entry_relation, NULL);
rewriteTargetListUD(parsetree, rt_entry, rt_entry_relation);
}
else if (event == CMD_DELETE)
{
rewriteTargetListUD(parsetree, rt_entry, rt_entry_relation);
}
else
elog(ERROR, "unrecognized commandType: %d", (int) event);
/*
* Collect and apply the appropriate rules.
*/
locks = matchLocks(event, rt_entry_relation->rd_rules,
result_relation, parsetree);
product_queries = fireRules(parsetree,
result_relation,
event,
locks,
&instead,
&returning,
&qual_product);
/*
* If there were no INSTEAD rules, and the target relation is a view
* without any INSTEAD OF triggers, see if the view can be
* automatically updated. If so, we perform the necessary query
* transformation here and add the resulting query to the
* product_queries list, so that it gets recursively rewritten if
* necessary.
*/
if (!instead && qual_product == NULL &&
rt_entry_relation->rd_rel->relkind == RELKIND_VIEW &&
!view_has_instead_trigger(rt_entry_relation, event))
{
/*
* This throws an error if the view can't be automatically
* updated, but that's OK since the query would fail at runtime
* anyway.
*/
parsetree = rewriteTargetView(parsetree, rt_entry_relation);
/*
* At this point product_queries contains any DO ALSO rule actions.
* Add the rewritten query before or after those. This must match
* the handling the original query would have gotten below, if
* we allowed it to be included again.
*/
if (parsetree->commandType == CMD_INSERT)
product_queries = lcons(parsetree, product_queries);
else
product_queries = lappend(product_queries, parsetree);
/*
* Set the "instead" flag, as if there had been an unqualified
* INSTEAD, to prevent the original query from being included a
* second time below. The transformation will have rewritten any
* RETURNING list, so we can also set "returning" to forestall
* throwing an error below.
*/
instead = true;
returning = true;
}
/*
* If we got any product queries, recursively rewrite them --- but
* first check for recursion!
*/
if (product_queries != NIL)
{
ListCell *n;
rewrite_event *rev;
foreach(n, rewrite_events)
{
rev = (rewrite_event *) lfirst(n);
if (rev->relation == RelationGetRelid(rt_entry_relation) &&
rev->event == event)
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("infinite recursion detected in rules for relation \"%s\"",
RelationGetRelationName(rt_entry_relation))));
}
rev = (rewrite_event *) palloc(sizeof(rewrite_event));
rev->relation = RelationGetRelid(rt_entry_relation);
rev->event = event;
rewrite_events = lcons(rev, rewrite_events);
foreach(n, product_queries)
{
Query *pt = (Query *) lfirst(n);
List *newstuff;
newstuff = RewriteQuery(pt, rewrite_events);
rewritten = list_concat(rewritten, newstuff);
}
rewrite_events = list_delete_first(rewrite_events);
}
/*
* If there is an INSTEAD, and the original query has a RETURNING, we
* have to have found a RETURNING in the rule(s), else fail. (Because
* DefineQueryRewrite only allows RETURNING in unconditional INSTEAD
* rules, there's no need to worry whether the substituted RETURNING
* will actually be executed --- it must be.)
*/
if ((instead || qual_product != NULL) &&
parsetree->returningList &&
!returning)
{
switch (event)
{
case CMD_INSERT:
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot perform INSERT RETURNING on relation \"%s\"",
RelationGetRelationName(rt_entry_relation)),
errhint("You need an unconditional ON INSERT DO INSTEAD rule with a RETURNING clause.")));
break;
case CMD_UPDATE:
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot perform UPDATE RETURNING on relation \"%s\"",
RelationGetRelationName(rt_entry_relation)),
errhint("You need an unconditional ON UPDATE DO INSTEAD rule with a RETURNING clause.")));
break;
case CMD_DELETE:
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot perform DELETE RETURNING on relation \"%s\"",
RelationGetRelationName(rt_entry_relation)),
errhint("You need an unconditional ON DELETE DO INSTEAD rule with a RETURNING clause.")));
break;
default:
elog(ERROR, "unrecognized commandType: %d",
(int) event);
break;
}
}
heap_close(rt_entry_relation, NoLock);
}
/*
* For INSERTs, the original query is done first; for UPDATE/DELETE, it is
* done last. This is needed because update and delete rule actions might
* not do anything if they are invoked after the update or delete is
* performed. The command counter increment between the query executions
* makes the deleted (and maybe the updated) tuples disappear so the scans
* for them in the rule actions cannot find them.
*
* If we found any unqualified INSTEAD, the original query is not done at
* all, in any form. Otherwise, we add the modified form if qualified
* INSTEADs were found, else the unmodified form.
*/
if (!instead)
{
if (parsetree->commandType == CMD_INSERT)
{
if (qual_product != NULL)
rewritten = lcons(qual_product, rewritten);
else
rewritten = lcons(parsetree, rewritten);
}
else
{
if (qual_product != NULL)
rewritten = lappend(rewritten, qual_product);
else
rewritten = lappend(rewritten, parsetree);
}
}
/*
* If the original query has a CTE list, and we generated more than one
* non-utility result query, we have to fail because we'll have copied the
* CTE list into each result query. That would break the expectation of
* single evaluation of CTEs. This could possibly be fixed by
* restructuring so that a CTE list can be shared across multiple Query
* and PlannableStatement nodes.
*/
if (parsetree->cteList != NIL)
{
int qcount = 0;
foreach(lc1, rewritten)
{
Query *q = (Query *) lfirst(lc1);
if (q->commandType != CMD_UTILITY)
qcount++;
}
if (qcount > 1)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("WITH cannot be used in a query that is rewritten by rules into multiple queries")));
}
return rewritten;
}
| static Query * rewriteRuleAction | ( | Query * | parsetree, | |
| Query * | rule_action, | |||
| Node * | rule_qual, | |||
| int | rt_index, | |||
| CmdType | event, | |||
| bool * | returning_flag | |||
| ) | [static] |
Definition at line 297 of file rewriteHandler.c.
References acquireLocksOnSubLinks(), AcquireRewriteLocks(), AddQual(), adjustJoinTreeList(), Assert, ChangeVarNodes(), checkExprHasSubLink(), CMD_INSERT, CMD_UPDATE, CMD_UTILITY, copyObject(), Query::cteList, CommonTableExpr::ctename, ereport, errcode(), errmsg(), ERROR, RangeTblEntry::funcexpr, getInsertSelectQuery(), Query::hasSubLinks, Query::jointree, lfirst, list_concat(), list_length(), NIL, NULL, OffsetVarNodes(), PRS2_NEW_VARNO, PRS2_OLD_VARNO, FromExpr::quals, rangeTableEntry_used(), REPLACEVARS_CHANGE_VARNO, REPLACEVARS_SUBSTITUTE_NULL, ReplaceVarsFromTargetList(), Query::resultRelation, Query::returningList, rt_fetch, Query::rtable, RTE_FUNCTION, RTE_VALUES, RangeTblEntry::rtekind, Query::targetList, and RangeTblEntry::values_lists.
Referenced by fireRules().
{
int current_varno,
new_varno;
int rt_length;
Query *sub_action;
Query **sub_action_ptr;
/*
* Make modifiable copies of rule action and qual (what we're passed are
* the stored versions in the relcache; don't touch 'em!).
*/
rule_action = (Query *) copyObject(rule_action);
rule_qual = (Node *) copyObject(rule_qual);
/*
* Acquire necessary locks and fix any deleted JOIN RTE entries.
*/
AcquireRewriteLocks(rule_action, false);
(void) acquireLocksOnSubLinks(rule_qual, NULL);
current_varno = rt_index;
rt_length = list_length(parsetree->rtable);
new_varno = PRS2_NEW_VARNO + rt_length;
/*
* Adjust rule action and qual to offset its varnos, so that we can merge
* its rtable with the main parsetree's rtable.
*
* If the rule action is an INSERT...SELECT, the OLD/NEW rtable entries
* will be in the SELECT part, and we have to modify that rather than the
* top-level INSERT (kluge!).
*/
sub_action = getInsertSelectQuery(rule_action, &sub_action_ptr);
OffsetVarNodes((Node *) sub_action, rt_length, 0);
OffsetVarNodes(rule_qual, rt_length, 0);
/* but references to OLD should point at original rt_index */
ChangeVarNodes((Node *) sub_action,
PRS2_OLD_VARNO + rt_length, rt_index, 0);
ChangeVarNodes(rule_qual,
PRS2_OLD_VARNO + rt_length, rt_index, 0);
/*
* Generate expanded rtable consisting of main parsetree's rtable plus
* rule action's rtable; this becomes the complete rtable for the rule
* action. Some of the entries may be unused after we finish rewriting,
* but we leave them all in place for two reasons:
*
* We'd have a much harder job to adjust the query's varnos if we
* selectively removed RT entries.
*
* If the rule is INSTEAD, then the original query won't be executed at
* all, and so its rtable must be preserved so that the executor will do
* the correct permissions checks on it.
*
* RT entries that are not referenced in the completed jointree will be
* ignored by the planner, so they do not affect query semantics. But any
* permissions checks specified in them will be applied during executor
* startup (see ExecCheckRTEPerms()). This allows us to check that the
* caller has, say, insert-permission on a view, when the view is not
* semantically referenced at all in the resulting query.
*
* When a rule is not INSTEAD, the permissions checks done on its copied
* RT entries will be redundant with those done during execution of the
* original query, but we don't bother to treat that case differently.
*
* NOTE: because planner will destructively alter rtable, we must ensure
* that rule action's rtable is separate and shares no substructure with
* the main rtable. Hence do a deep copy here.
*/
sub_action->rtable = list_concat((List *) copyObject(parsetree->rtable),
sub_action->rtable);
/*
* There could have been some SubLinks in parsetree's rtable, in which
* case we'd better mark the sub_action correctly.
*/
if (parsetree->hasSubLinks && !sub_action->hasSubLinks)
{
ListCell *lc;
foreach(lc, parsetree->rtable)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
switch (rte->rtekind)
{
case RTE_FUNCTION:
sub_action->hasSubLinks =
checkExprHasSubLink(rte->funcexpr);
break;
case RTE_VALUES:
sub_action->hasSubLinks =
checkExprHasSubLink((Node *) rte->values_lists);
break;
default:
/* other RTE types don't contain bare expressions */
break;
}
if (sub_action->hasSubLinks)
break; /* no need to keep scanning rtable */
}
}
/*
* Each rule action's jointree should be the main parsetree's jointree
* plus that rule's jointree, but usually *without* the original rtindex
* that we're replacing (if present, which it won't be for INSERT). Note
* that if the rule action refers to OLD, its jointree will add a
* reference to rt_index. If the rule action doesn't refer to OLD, but
* either the rule_qual or the user query quals do, then we need to keep
* the original rtindex in the jointree to provide data for the quals. We
* don't want the original rtindex to be joined twice, however, so avoid
* keeping it if the rule action mentions it.
*
* As above, the action's jointree must not share substructure with the
* main parsetree's.
*/
if (sub_action->commandType != CMD_UTILITY)
{
bool keeporig;
List *newjointree;
Assert(sub_action->jointree != NULL);
keeporig = (!rangeTableEntry_used((Node *) sub_action->jointree,
rt_index, 0)) &&
(rangeTableEntry_used(rule_qual, rt_index, 0) ||
rangeTableEntry_used(parsetree->jointree->quals, rt_index, 0));
newjointree = adjustJoinTreeList(parsetree, !keeporig, rt_index);
if (newjointree != NIL)
{
/*
* If sub_action is a setop, manipulating its jointree will do no
* good at all, because the jointree is dummy. (Perhaps someday
* we could push the joining and quals down to the member
* statements of the setop?)
*/
if (sub_action->setOperations != NULL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("conditional UNION/INTERSECT/EXCEPT statements are not implemented")));
sub_action->jointree->fromlist =
list_concat(newjointree, sub_action->jointree->fromlist);
/*
* There could have been some SubLinks in newjointree, in which
* case we'd better mark the sub_action correctly.
*/
if (parsetree->hasSubLinks && !sub_action->hasSubLinks)
sub_action->hasSubLinks =
checkExprHasSubLink((Node *) newjointree);
}
}
/*
* If the original query has any CTEs, copy them into the rule action. But
* we don't need them for a utility action.
*/
if (parsetree->cteList != NIL && sub_action->commandType != CMD_UTILITY)
{
ListCell *lc;
/*
* Annoying implementation restriction: because CTEs are identified by
* name within a cteList, we can't merge a CTE from the original query
* if it has the same name as any CTE in the rule action.
*
* This could possibly be fixed by using some sort of internally
* generated ID, instead of names, to link CTE RTEs to their CTEs.
*/
foreach(lc, parsetree->cteList)
{
CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
ListCell *lc2;
foreach(lc2, sub_action->cteList)
{
CommonTableExpr *cte2 = (CommonTableExpr *) lfirst(lc2);
if (strcmp(cte->ctename, cte2->ctename) == 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("WITH query name \"%s\" appears in both a rule action and the query being rewritten",
cte->ctename)));
}
}
/* OK, it's safe to combine the CTE lists */
sub_action->cteList = list_concat(sub_action->cteList,
copyObject(parsetree->cteList));
}
/*
* Event Qualification forces copying of parsetree and splitting into two
* queries one w/rule_qual, one w/NOT rule_qual. Also add user query qual
* onto rule action
*/
AddQual(sub_action, rule_qual);
AddQual(sub_action, parsetree->jointree->quals);
/*
* Rewrite new.attribute with right hand side of target-list entry for
* appropriate field name in insert/update.
*
* KLUGE ALERT: since ReplaceVarsFromTargetList returns a mutated copy, we
* can't just apply it to sub_action; we have to remember to update the
* sublink inside rule_action, too.
*/
if ((event == CMD_INSERT || event == CMD_UPDATE) &&
sub_action->commandType != CMD_UTILITY)
{
sub_action = (Query *)
ReplaceVarsFromTargetList((Node *) sub_action,
new_varno,
0,
rt_fetch(new_varno, sub_action->rtable),
parsetree->targetList,
(event == CMD_UPDATE) ?
REPLACEVARS_CHANGE_VARNO :
REPLACEVARS_SUBSTITUTE_NULL,
current_varno,
NULL);
if (sub_action_ptr)
*sub_action_ptr = sub_action;
else
rule_action = sub_action;
}
/*
* If rule_action has a RETURNING clause, then either throw it away if the
* triggering query has no RETURNING clause, or rewrite it to emit what
* the triggering query's RETURNING clause asks for. Throw an error if
* more than one rule has a RETURNING clause.
*/
if (!parsetree->returningList)
rule_action->returningList = NIL;
else if (rule_action->returningList)
{
if (*returning_flag)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot have RETURNING lists in multiple rules")));
*returning_flag = true;
rule_action->returningList = (List *)
ReplaceVarsFromTargetList((Node *) parsetree->returningList,
parsetree->resultRelation,
0,
rt_fetch(parsetree->resultRelation,
parsetree->rtable),
rule_action->returningList,
REPLACEVARS_REPORT_ERROR,
0,
&rule_action->hasSubLinks);
/*
* There could have been some SubLinks in parsetree's returningList,
* in which case we'd better mark the rule_action correctly.
*/
if (parsetree->hasSubLinks && !rule_action->hasSubLinks)
rule_action->hasSubLinks =
checkExprHasSubLink((Node *) rule_action->returningList);
}
return rule_action;
}
| static void rewriteTargetListIU | ( | Query * | parsetree, | |
| Relation | target_relation, | |||
| List ** | attrno_list | |||
| ) | [static] |
Definition at line 649 of file rewriteHandler.c.
References tupleDesc::attrs, build_column_default(), CMD_INSERT, CMD_UPDATE, COERCE_IMPLICIT_CAST, coerce_to_domain(), Query::commandType, elog, ERROR, TargetEntry::expr, flatCopyTargetEntry(), InvalidOid, IsA, lappend(), lappend_int(), lfirst, list_concat(), makeConst(), makeTargetEntry(), makeVar(), NameStr, NULL, palloc0(), pfree(), process_matched_tle(), pstrdup(), RelationData::rd_att, RelationData::rd_rel, RelationGetNumberOfAttributes, RELKIND_VIEW, TargetEntry::resjunk, TargetEntry::resno, Query::resultRelation, and Query::targetList.
Referenced by RewriteQuery().
{
CmdType commandType = parsetree->commandType;
TargetEntry **new_tles;
List *new_tlist = NIL;
List *junk_tlist = NIL;
Form_pg_attribute att_tup;
int attrno,
next_junk_attrno,
numattrs;
ListCell *temp;
if (attrno_list) /* initialize optional result list */
*attrno_list = NIL;
/*
* We process the normal (non-junk) attributes by scanning the input tlist
* once and transferring TLEs into an array, then scanning the array to
* build an output tlist. This avoids O(N^2) behavior for large numbers
* of attributes.
*
* Junk attributes are tossed into a separate list during the same tlist
* scan, then appended to the reconstructed tlist.
*/
numattrs = RelationGetNumberOfAttributes(target_relation);
new_tles = (TargetEntry **) palloc0(numattrs * sizeof(TargetEntry *));
next_junk_attrno = numattrs + 1;
foreach(temp, parsetree->targetList)
{
TargetEntry *old_tle = (TargetEntry *) lfirst(temp);
if (!old_tle->resjunk)
{
/* Normal attr: stash it into new_tles[] */
attrno = old_tle->resno;
if (attrno < 1 || attrno > numattrs)
elog(ERROR, "bogus resno %d in targetlist", attrno);
att_tup = target_relation->rd_att->attrs[attrno - 1];
/* put attrno into attrno_list even if it's dropped */
if (attrno_list)
*attrno_list = lappend_int(*attrno_list, attrno);
/* We can (and must) ignore deleted attributes */
if (att_tup->attisdropped)
continue;
/* Merge with any prior assignment to same attribute */
new_tles[attrno - 1] =
process_matched_tle(old_tle,
new_tles[attrno - 1],
NameStr(att_tup->attname));
}
else
{
/*
* Copy all resjunk tlist entries to junk_tlist, and assign them
* resnos above the last real resno.
*
* Typical junk entries include ORDER BY or GROUP BY expressions
* (are these actually possible in an INSERT or UPDATE?), system
* attribute references, etc.
*/
/* Get the resno right, but don't copy unnecessarily */
if (old_tle->resno != next_junk_attrno)
{
old_tle = flatCopyTargetEntry(old_tle);
old_tle->resno = next_junk_attrno;
}
junk_tlist = lappend(junk_tlist, old_tle);
next_junk_attrno++;
}
}
for (attrno = 1; attrno <= numattrs; attrno++)
{
TargetEntry *new_tle = new_tles[attrno - 1];
att_tup = target_relation->rd_att->attrs[attrno - 1];
/* We can (and must) ignore deleted attributes */
if (att_tup->attisdropped)
continue;
/*
* Handle the two cases where we need to insert a default expression:
* it's an INSERT and there's no tlist entry for the column, or the
* tlist entry is a DEFAULT placeholder node.
*/
if ((new_tle == NULL && commandType == CMD_INSERT) ||
(new_tle && new_tle->expr && IsA(new_tle->expr, SetToDefault)))
{
Node *new_expr;
new_expr = build_column_default(target_relation, attrno);
/*
* If there is no default (ie, default is effectively NULL), we
* can omit the tlist entry in the INSERT case, since the planner
* can insert a NULL for itself, and there's no point in spending
* any more rewriter cycles on the entry. But in the UPDATE case
* we've got to explicitly set the column to NULL.
*/
if (!new_expr)
{
if (commandType == CMD_INSERT)
new_tle = NULL;
else
{
new_expr = (Node *) makeConst(att_tup->atttypid,
-1,
att_tup->attcollation,
att_tup->attlen,
(Datum) 0,
true, /* isnull */
att_tup->attbyval);
/* this is to catch a NOT NULL domain constraint */
new_expr = coerce_to_domain(new_expr,
InvalidOid, -1,
att_tup->atttypid,
COERCE_IMPLICIT_CAST,
-1,
false,
false);
}
}
if (new_expr)
new_tle = makeTargetEntry((Expr *) new_expr,
attrno,
pstrdup(NameStr(att_tup->attname)),
false);
}
/*
* For an UPDATE on a view, provide a dummy entry whenever there is no
* explicit assignment.
*/
if (new_tle == NULL && commandType == CMD_UPDATE &&
target_relation->rd_rel->relkind == RELKIND_VIEW)
{
Node *new_expr;
new_expr = (Node *) makeVar(parsetree->resultRelation,
attrno,
att_tup->atttypid,
att_tup->atttypmod,
att_tup->attcollation,
0);
new_tle = makeTargetEntry((Expr *) new_expr,
attrno,
pstrdup(NameStr(att_tup->attname)),
false);
}
if (new_tle)
new_tlist = lappend(new_tlist, new_tle);
}
pfree(new_tles);
parsetree->targetList = list_concat(new_tlist, junk_tlist);
}
| static void rewriteTargetListUD | ( | Query * | parsetree, | |
| RangeTblEntry * | target_rte, | |||
| Relation | target_relation | |||
| ) | [static] |
Definition at line 1166 of file rewriteHandler.c.
References FdwRoutine::AddForeignUpdateTargets, GetFdwRoutineForRelation(), InvalidOid, lappend(), list_length(), makeTargetEntry(), makeVar(), makeWholeRowVar(), NULL, pstrdup(), RelationData::rd_rel, RELKIND_FOREIGN_TABLE, RELKIND_MATVIEW, RELKIND_RELATION, Query::resultRelation, SelfItemPointerAttributeNumber, Query::targetList, and TIDOID.
Referenced by RewriteQuery().
{
Var *var;
const char *attrname;
TargetEntry *tle;
if (target_relation->rd_rel->relkind == RELKIND_RELATION ||
target_relation->rd_rel->relkind == RELKIND_MATVIEW)
{
/*
* Emit CTID so that executor can find the row to update or delete.
*/
var = makeVar(parsetree->resultRelation,
SelfItemPointerAttributeNumber,
TIDOID,
-1,
InvalidOid,
0);
attrname = "ctid";
}
else if (target_relation->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
{
/*
* Let the foreign table's FDW add whatever junk TLEs it wants.
*/
FdwRoutine *fdwroutine;
fdwroutine = GetFdwRoutineForRelation(target_relation, false);
if (fdwroutine->AddForeignUpdateTargets != NULL)
fdwroutine->AddForeignUpdateTargets(parsetree, target_rte,
target_relation);
return;
}
else
{
/*
* Emit whole-row Var so that executor will have the "old" view row to
* pass to the INSTEAD OF trigger.
*/
var = makeWholeRowVar(target_rte,
parsetree->resultRelation,
0,
false);
attrname = "wholerow";
}
tle = makeTargetEntry((Expr *) var,
list_length(parsetree->targetList) + 1,
pstrdup(attrname),
true);
parsetree->targetList = lappend(parsetree->targetList, tle);
}
Definition at line 2240 of file rewriteHandler.c.
References _, AddQual(), adjust_view_column_set(), Assert, bms_is_empty(), ChangeVarNodes(), RangeTblEntry::checkAsUser, CMD_DELETE, CMD_INSERT, CMD_UPDATE, Query::commandType, copyObject(), elog, ereport, errcode(), errdetail_internal(), errhint(), errmsg(), ERROR, TargetEntry::expr, FromExpr::fromlist, get_tle_by_resno(), get_view_query(), Query::hasSubLinks, heap_close, heap_open(), IsA, Query::jointree, lappend(), lfirst, linitial, list_delete_ptr(), list_length(), llast, RangeTblEntry::modifiedCols, NoLock, NULL, FromExpr::quals, RelationData::rd_rel, RelationGetRelationName, RangeTblEntry::relid, RangeTblEntry::relkind, ReplaceVarsFromTargetList(), RangeTblEntry::requiredPerms, TargetEntry::resjunk, TargetEntry::resno, Query::resultRelation, RowExclusiveLock, rt_fetch, Query::rtable, RTE_RELATION, RangeTblEntry::rtekind, RangeTblRef::rtindex, Query::targetList, and view_is_auto_updatable().
Referenced by RewriteQuery().
{
const char *auto_update_detail;
Query *viewquery;
RangeTblRef *rtr;
int base_rt_index;
int new_rt_index;
RangeTblEntry *base_rte;
RangeTblEntry *view_rte;
RangeTblEntry *new_rte;
Relation base_rel;
List *view_targetlist;
ListCell *lc;
/* The view must be simply updatable, else fail */
auto_update_detail = view_is_auto_updatable(view);
if (auto_update_detail)
{
/* messages here should match execMain.c's CheckValidResultRel */
switch (parsetree->commandType)
{
case CMD_INSERT:
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("cannot insert into view \"%s\"",
RelationGetRelationName(view)),
errdetail_internal("%s", _(auto_update_detail)),
errhint("To make the view insertable, provide an unconditional ON INSERT DO INSTEAD rule or an INSTEAD OF INSERT trigger.")));
break;
case CMD_UPDATE:
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("cannot update view \"%s\"",
RelationGetRelationName(view)),
errdetail_internal("%s", _(auto_update_detail)),
errhint("To make the view updatable, provide an unconditional ON UPDATE DO INSTEAD rule or an INSTEAD OF UPDATE trigger.")));
break;
case CMD_DELETE:
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("cannot delete from view \"%s\"",
RelationGetRelationName(view)),
errdetail_internal("%s", _(auto_update_detail)),
errhint("To make the view updatable, provide an unconditional ON DELETE DO INSTEAD rule or an INSTEAD OF DELETE trigger.")));
break;
default:
elog(ERROR, "unrecognized CmdType: %d",
(int) parsetree->commandType);
break;
}
}
/* Locate RTE describing the view in the outer query */
view_rte = rt_fetch(parsetree->resultRelation, parsetree->rtable);
/*
* If we get here, view_is_auto_updatable() has verified that the view
* contains a single base relation.
*/
viewquery = get_view_query(view);
Assert(list_length(viewquery->jointree->fromlist) == 1);
rtr = (RangeTblRef *) linitial(viewquery->jointree->fromlist);
Assert(IsA(rtr, RangeTblRef));
base_rt_index = rtr->rtindex;
base_rte = rt_fetch(base_rt_index, viewquery->rtable);
Assert(base_rte->rtekind == RTE_RELATION);
/*
* Up to now, the base relation hasn't been touched at all in our query.
* We need to acquire lock on it before we try to do anything with it.
* (The subsequent recursive call of RewriteQuery will suppose that we
* already have the right lock!) Since it will become the query target
* relation, RowExclusiveLock is always the right thing.
*/
base_rel = heap_open(base_rte->relid, RowExclusiveLock);
/*
* While we have the relation open, update the RTE's relkind, just in case
* it changed since this view was made (cf. AcquireRewriteLocks).
*/
base_rte->relkind = base_rel->rd_rel->relkind;
heap_close(base_rel, NoLock);
/*
* Create a new target RTE describing the base relation, and add it to the
* outer query's rangetable. (What's happening in the next few steps is
* very much like what the planner would do to "pull up" the view into the
* outer query. Perhaps someday we should refactor things enough so that
* we can share code with the planner.)
*/
new_rte = (RangeTblEntry *) copyObject(base_rte);
parsetree->rtable = lappend(parsetree->rtable, new_rte);
new_rt_index = list_length(parsetree->rtable);
/*
* Make a copy of the view's targetlist, adjusting its Vars to reference
* the new target RTE, ie make their varnos be new_rt_index instead of
* base_rt_index. There can be no Vars for other rels in the tlist, so
* this is sufficient to pull up the tlist expressions for use in the
* outer query. The tlist will provide the replacement expressions used
* by ReplaceVarsFromTargetList below.
*/
view_targetlist = copyObject(viewquery->targetList);
ChangeVarNodes((Node *) view_targetlist,
base_rt_index,
new_rt_index,
0);
/*
* Mark the new target RTE for the permissions checks that we want to
* enforce against the view owner, as distinct from the query caller. At
* the relation level, require the same INSERT/UPDATE/DELETE permissions
* that the query caller needs against the view. We drop the ACL_SELECT
* bit that is presumably in new_rte->requiredPerms initially.
*
* Note: the original view RTE remains in the query's rangetable list.
* Although it will be unused in the query plan, we need it there so that
* the executor still performs appropriate permissions checks for the
* query caller's use of the view.
*/
new_rte->checkAsUser = view->rd_rel->relowner;
new_rte->requiredPerms = view_rte->requiredPerms;
/*
* Now for the per-column permissions bits.
*
* Initially, new_rte contains selectedCols permission check bits for all
* base-rel columns referenced by the view, but since the view is a SELECT
* query its modifiedCols is empty. We set modifiedCols to include all
* the columns the outer query is trying to modify, adjusting the column
* numbers as needed. But we leave selectedCols as-is, so the view owner
* must have read permission for all columns used in the view definition,
* even if some of them are not read by the outer query. We could try to
* limit selectedCols to only columns used in the transformed query, but
* that does not correspond to what happens in ordinary SELECT usage of a
* view: all referenced columns must have read permission, even if
* optimization finds that some of them can be discarded during query
* transformation. The flattening we're doing here is an optional
* optimization, too. (If you are unpersuaded and want to change this,
* note that applying adjust_view_column_set to view_rte->selectedCols is
* clearly *not* the right answer, since that neglects base-rel columns
* used in the view's WHERE quals.)
*
* This step needs the modified view targetlist, so we have to do things
* in this order.
*/
Assert(bms_is_empty(new_rte->modifiedCols));
new_rte->modifiedCols = adjust_view_column_set(view_rte->modifiedCols,
view_targetlist);
/*
* For UPDATE/DELETE, rewriteTargetListUD will have added a wholerow junk
* TLE for the view to the end of the targetlist, which we no longer need.
* Remove it to avoid unnecessary work when we process the targetlist.
* Note that when we recurse through rewriteQuery a new junk TLE will be
* added to allow the executor to find the proper row in the new target
* relation. (So, if we failed to do this, we might have multiple junk
* TLEs with the same name, which would be disastrous.)
*/
if (parsetree->commandType != CMD_INSERT)
{
TargetEntry *tle = (TargetEntry *) llast(parsetree->targetList);
Assert(tle->resjunk);
Assert(IsA(tle->expr, Var) &&
((Var *) tle->expr)->varno == parsetree->resultRelation &&
((Var *) tle->expr)->varattno == 0);
parsetree->targetList = list_delete_ptr(parsetree->targetList, tle);
}
/*
* Now update all Vars in the outer query that reference the view to
* reference the appropriate column of the base relation instead.
*/
parsetree = (Query *)
ReplaceVarsFromTargetList((Node *) parsetree,
parsetree->resultRelation,
0,
view_rte,
view_targetlist,
REPLACEVARS_REPORT_ERROR,
0,
&parsetree->hasSubLinks);
/*
* Update all other RTI references in the query that point to the view
* (for example, parsetree->resultRelation itself) to point to the new
* base relation instead. Vars will not be affected since none of them
* reference parsetree->resultRelation any longer.
*/
ChangeVarNodes((Node *) parsetree,
parsetree->resultRelation,
new_rt_index,
0);
Assert(parsetree->resultRelation == new_rt_index);
/*
* For INSERT/UPDATE we must also update resnos in the targetlist to refer
* to columns of the base relation, since those indicate the target
* columns to be affected.
*
* Note that this destroys the resno ordering of the targetlist, but that
* will be fixed when we recurse through rewriteQuery, which will invoke
* rewriteTargetListIU again on the updated targetlist.
*/
if (parsetree->commandType != CMD_DELETE)
{
foreach(lc, parsetree->targetList)
{
TargetEntry *tle = (TargetEntry *) lfirst(lc);
TargetEntry *view_tle;
if (tle->resjunk)
continue;
view_tle = get_tle_by_resno(view_targetlist, tle->resno);
if (view_tle != NULL && !view_tle->resjunk && IsA(view_tle->expr, Var))
tle->resno = ((Var *) view_tle->expr)->varattno;
else
elog(ERROR, "attribute number %d not found in view targetlist",
tle->resno);
}
}
/*
* For UPDATE/DELETE, pull up any WHERE quals from the view. We know that
* any Vars in the quals must reference the one base relation, so we need
* only adjust their varnos to reference the new target (just the same as
* we did with the view targetlist).
*
* For INSERT, the view's quals can be ignored for now. When we implement
* WITH CHECK OPTION, this might be a good place to collect them.
*/
if (parsetree->commandType != CMD_INSERT &&
viewquery->jointree->quals != NULL)
{
Node *viewqual = (Node *) copyObject(viewquery->jointree->quals);
ChangeVarNodes(viewqual, base_rt_index, new_rt_index, 0);
AddQual(parsetree, (Node *) viewqual);
}
return parsetree;
}
| static void rewriteValuesRTE | ( | RangeTblEntry * | rte, | |
| Relation | target_relation, | |||
| List * | attrnos | |||
| ) | [static] |
Definition at line 1078 of file rewriteHandler.c.
References Assert, tupleDesc::attrs, build_column_default(), COERCE_IMPLICIT_CAST, coerce_to_domain(), forboth, InvalidOid, IsA, lappend(), lfirst, lfirst_int, linitial, list_length(), makeConst(), RelationData::rd_att, searchForDefault(), and RangeTblEntry::values_lists.
Referenced by RewriteQuery().
{
List *newValues;
ListCell *lc;
/*
* Rebuilding all the lists is a pretty expensive proposition in a big
* VALUES list, and it's a waste of time if there aren't any DEFAULT
* placeholders. So first scan to see if there are any.
*/
if (!searchForDefault(rte))
return; /* nothing to do */
/* Check list lengths (we can assume all the VALUES sublists are alike) */
Assert(list_length(attrnos) == list_length(linitial(rte->values_lists)));
newValues = NIL;
foreach(lc, rte->values_lists)
{
List *sublist = (List *) lfirst(lc);
List *newList = NIL;
ListCell *lc2;
ListCell *lc3;
forboth(lc2, sublist, lc3, attrnos)
{
Node *col = (Node *) lfirst(lc2);
int attrno = lfirst_int(lc3);
if (IsA(col, SetToDefault))
{
Form_pg_attribute att_tup;
Node *new_expr;
att_tup = target_relation->rd_att->attrs[attrno - 1];
if (!att_tup->attisdropped)
new_expr = build_column_default(target_relation, attrno);
else
new_expr = NULL; /* force a NULL if dropped */
/*
* If there is no default (ie, default is effectively NULL),
* we've got to explicitly set the column to NULL.
*/
if (!new_expr)
{
new_expr = (Node *) makeConst(att_tup->atttypid,
-1,
att_tup->attcollation,
att_tup->attlen,
(Datum) 0,
true, /* isnull */
att_tup->attbyval);
/* this is to catch a NOT NULL domain constraint */
new_expr = coerce_to_domain(new_expr,
InvalidOid, -1,
att_tup->atttypid,
COERCE_IMPLICIT_CAST,
-1,
false,
false);
}
newList = lappend(newList, new_expr);
}
else
newList = lappend(newList, col);
}
newValues = lappend(newValues, newList);
}
rte->values_lists = newValues;
}
| static bool searchForDefault | ( | RangeTblEntry * | rte | ) | [static] |
Definition at line 1046 of file rewriteHandler.c.
References IsA, lfirst, and RangeTblEntry::values_lists.
Referenced by rewriteValuesRTE().
Definition at line 1902 of file rewriteHandler.c.
References CMD_DELETE, CMD_INSERT, CMD_UPDATE, elog, ERROR, TriggerDesc::trig_delete_instead_row, TriggerDesc::trig_insert_instead_row, TriggerDesc::trig_update_instead_row, and RelationData::trigdesc.
Referenced by RewriteQuery().
{
TriggerDesc *trigDesc = view->trigdesc;
switch (event)
{
case CMD_INSERT:
if (trigDesc && trigDesc->trig_insert_instead_row)
return true;
break;
case CMD_UPDATE:
if (trigDesc && trigDesc->trig_update_instead_row)
return true;
break;
case CMD_DELETE:
if (trigDesc && trigDesc->trig_delete_instead_row)
return true;
break;
default:
elog(ERROR, "unrecognized CmdType: %d", (int) event);
break;
}
return false;
}
| static const char* view_is_auto_updatable | ( | Relation | view | ) | [static] |
Definition at line 1944 of file rewriteHandler.c.
References bms_add_member(), bms_free(), bms_is_member(), Query::cteList, Query::distinctClause, TargetEntry::expr, FromExpr::fromlist, get_view_query(), gettext_noop, Query::groupClause, Query::havingQual, IsA, Query::jointree, lfirst, Query::limitCount, Query::limitOffset, linitial, list_length(), NIL, NULL, RelationIsSecurityView, RangeTblEntry::relkind, RELKIND_RELATION, RELKIND_VIEW, TargetEntry::resjunk, rt_fetch, Query::rtable, RTE_RELATION, RangeTblEntry::rtekind, RangeTblRef::rtindex, Query::setOperations, Query::targetList, Var::varattno, Var::varlevelsup, and Var::varno.
Referenced by relation_is_updatable(), and rewriteTargetView().
{
Query *viewquery = get_view_query(view);
RangeTblRef *rtr;
RangeTblEntry *base_rte;
Bitmapset *bms;
ListCell *cell;
/*----------
* Check if the view is simply updatable. According to SQL-92 this means:
* - No DISTINCT clause.
* - Each TLE is a column reference, and each column appears at most once.
* - FROM contains exactly one base relation.
* - No GROUP BY or HAVING clauses.
* - No set operations (UNION, INTERSECT or EXCEPT).
* - No sub-queries in the WHERE clause that reference the target table.
*
* We ignore that last restriction since it would be complex to enforce
* and there isn't any actual benefit to disallowing sub-queries. (The
* semantic issues that the standard is presumably concerned about don't
* arise in Postgres, since any such sub-query will not see any updates
* executed by the outer query anyway, thanks to MVCC snapshotting.)
*
* In addition we impose these constraints, involving features that are
* not part of SQL-92:
* - No CTEs (WITH clauses).
* - No OFFSET or LIMIT clauses (this matches a SQL:2008 restriction).
* - No system columns (including whole-row references) in the tlist.
*
* Note that we do these checks without recursively expanding the view.
* If the base relation is a view, we'll recursively deal with it later.
*----------
*/
if (viewquery->distinctClause != NIL)
return gettext_noop("Views containing DISTINCT are not automatically updatable.");
if (viewquery->groupClause != NIL)
return gettext_noop("Views containing GROUP BY are not automatically updatable.");
if (viewquery->havingQual != NULL)
return gettext_noop("Views containing HAVING are not automatically updatable.");
if (viewquery->setOperations != NULL)
return gettext_noop("Views containing UNION, INTERSECT, or EXCEPT are not automatically updatable.");
if (viewquery->cteList != NIL)
return gettext_noop("Views containing WITH are not automatically updatable.");
if (viewquery->limitOffset != NULL || viewquery->limitCount != NULL)
return gettext_noop("Views containing LIMIT or OFFSET are not automatically updatable.");
/*
* For now, we also don't support security-barrier views, because of the
* difficulty of keeping upper-level qual expressions away from
* lower-level data. This might get relaxed in future.
*/
if (RelationIsSecurityView(view))
return gettext_noop("Security-barrier views are not automatically updatable.");
/*
* The view query should select from a single base relation, which must be
* a table or another view.
*/
if (list_length(viewquery->jointree->fromlist) != 1)
return gettext_noop("Views that do not select from a single table or view are not automatically updatable.");
rtr = (RangeTblRef *) linitial(viewquery->jointree->fromlist);
if (!IsA(rtr, RangeTblRef))
return gettext_noop("Views that do not select from a single table or view are not automatically updatable.");
base_rte = rt_fetch(rtr->rtindex, viewquery->rtable);
if (base_rte->rtekind != RTE_RELATION ||
(base_rte->relkind != RELKIND_RELATION &&
base_rte->relkind != RELKIND_VIEW))
return gettext_noop("Views that do not select from a single table or view are not automatically updatable.");
/*
* The view's targetlist entries should all be Vars referring to user
* columns of the base relation, and no two should refer to the same
* column.
*
* Note however that we should ignore resjunk entries. This proviso is
* relevant because ORDER BY is not disallowed, and we shouldn't reject a
* view defined like "SELECT * FROM t ORDER BY a+b".
*/
bms = NULL;
foreach(cell, viewquery->targetList)
{
TargetEntry *tle = (TargetEntry *) lfirst(cell);
Var *var = (Var *) tle->expr;
if (tle->resjunk)
continue;
if (!IsA(var, Var) ||
var->varno != rtr->rtindex ||
var->varlevelsup != 0)
return gettext_noop("Views that return columns that are not columns of their base relation are not automatically updatable.");
if (var->varattno < 0)
return gettext_noop("Views that return system columns are not automatically updatable.");
if (var->varattno == 0)
return gettext_noop("Views that return whole-row references are not automatically updatable.");
if (bms_is_member(var->varattno, bms))
return gettext_noop("Views that return the same column more than once are not automatically updatable.");
bms = bms_add_member(bms, var->varattno);
}
bms_free(bms); /* just for cleanliness */
return NULL; /* the view is simply updatable */
}
1.7.1