pg_largeobject.c File Reference

#include "postgres.h"
#include "access/genam.h"
#include "access/heapam.h"
#include "access/htup_details.h"
#include "access/sysattr.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/pg_largeobject.h"
#include "catalog/pg_largeobject_metadata.h"
#include "miscadmin.h"
#include "utils/acl.h"
#include "utils/fmgroids.h"
#include "utils/rel.h"
#include "utils/tqual.h"

Include dependency graph for pg_largeobject.c:

Go to the source code of this file.

Functions
Oid	LargeObjectCreate (Oid loid)
void	LargeObjectDrop (Oid loid)
bool	LargeObjectExists (Oid loid)

---

Function Documentation

Oid LargeObjectCreate

(

Oid

loid

)

Definition at line 40 of file pg_largeobject.c.

References Anum_pg_largeobject_metadata_lomacl, Anum_pg_largeobject_metadata_lomowner, Assert, CatalogUpdateIndexes(), GetUserId(), heap_close, heap_form_tuple(), heap_freetuple(), heap_open(), HeapTupleSetOid, LargeObjectMetadataRelationId, ObjectIdGetDatum, OidIsValid, RelationGetDescr, RowExclusiveLock, simple_heap_insert(), and values.

Referenced by inv_create().

{
    Relation    pg_lo_meta;
    HeapTuple   ntup;
    Oid         loid_new;
    Datum       values[Natts_pg_largeobject_metadata];
    bool        nulls[Natts_pg_largeobject_metadata];

    pg_lo_meta = heap_open(LargeObjectMetadataRelationId,
                           RowExclusiveLock);

    /*
     * Insert metadata of the largeobject
     */
    memset(values, 0, sizeof(values));
    memset(nulls, false, sizeof(nulls));

    values[Anum_pg_largeobject_metadata_lomowner - 1]
        = ObjectIdGetDatum(GetUserId());
    nulls[Anum_pg_largeobject_metadata_lomacl - 1] = true;

    ntup = heap_form_tuple(RelationGetDescr(pg_lo_meta),
                           values, nulls);
    if (OidIsValid(loid))
        HeapTupleSetOid(ntup, loid);

    loid_new = simple_heap_insert(pg_lo_meta, ntup);
    Assert(!OidIsValid(loid) || loid == loid_new);

    CatalogUpdateIndexes(pg_lo_meta, ntup);

    heap_freetuple(ntup);

    heap_close(pg_lo_meta, RowExclusiveLock);

    return loid_new;
}

void LargeObjectDrop

(

Oid

loid

)

Definition at line 83 of file pg_largeobject.c.

References Anum_pg_largeobject_loid, BTEqualStrategyNumber, ereport, errcode(), errmsg(), ERROR, heap_close, heap_open(), HeapTupleIsValid, LargeObjectLOidPNIndexId, LargeObjectMetadataOidIndexId, LargeObjectMetadataRelationId, LargeObjectRelationId, ObjectIdAttributeNumber, ObjectIdGetDatum, RowExclusiveLock, ScanKeyInit(), simple_heap_delete(), SnapshotNow, systable_beginscan(), systable_endscan(), systable_getnext(), and HeapTupleData::t_self.

Referenced by doDeletion().

{
    Relation    pg_lo_meta;
    Relation    pg_largeobject;
    ScanKeyData skey[1];
    SysScanDesc scan;
    HeapTuple   tuple;

    pg_lo_meta = heap_open(LargeObjectMetadataRelationId,
                           RowExclusiveLock);

    pg_largeobject = heap_open(LargeObjectRelationId,
                               RowExclusiveLock);

    /*
     * Delete an entry from pg_largeobject_metadata
     */
    ScanKeyInit(&skey[0],
                ObjectIdAttributeNumber,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(loid));

    scan = systable_beginscan(pg_lo_meta,
                              LargeObjectMetadataOidIndexId, true,
                              SnapshotNow, 1, skey);

    tuple = systable_getnext(scan);
    if (!HeapTupleIsValid(tuple))
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_OBJECT),
                 errmsg("large object %u does not exist", loid)));

    simple_heap_delete(pg_lo_meta, &tuple->t_self);

    systable_endscan(scan);

    /*
     * Delete all the associated entries from pg_largeobject
     */
    ScanKeyInit(&skey[0],
                Anum_pg_largeobject_loid,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(loid));

    scan = systable_beginscan(pg_largeobject,
                              LargeObjectLOidPNIndexId, true,
                              SnapshotNow, 1, skey);
    while (HeapTupleIsValid(tuple = systable_getnext(scan)))
    {
        simple_heap_delete(pg_largeobject, &tuple->t_self);
    }

    systable_endscan(scan);

    heap_close(pg_largeobject, RowExclusiveLock);

    heap_close(pg_lo_meta, RowExclusiveLock);
}

bool LargeObjectExists

(

Oid

loid

)

Definition at line 155 of file pg_largeobject.c.

References AccessShareLock, BTEqualStrategyNumber, heap_close, heap_open(), HeapTupleIsValid, LargeObjectMetadataOidIndexId, LargeObjectMetadataRelationId, ObjectIdAttributeNumber, ObjectIdGetDatum, ScanKeyInit(), SnapshotNow, systable_beginscan(), systable_endscan(), and systable_getnext().

Referenced by get_object_address(), and objectNamesToOids().

{
    Relation    pg_lo_meta;
    ScanKeyData skey[1];
    SysScanDesc sd;
    HeapTuple   tuple;
    bool        retval = false;

    ScanKeyInit(&skey[0],
                ObjectIdAttributeNumber,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(loid));

    pg_lo_meta = heap_open(LargeObjectMetadataRelationId,
                           AccessShareLock);

    sd = systable_beginscan(pg_lo_meta,
                            LargeObjectMetadataOidIndexId, true,
                            SnapshotNow, 1, skey);

    tuple = systable_getnext(sd);
    if (HeapTupleIsValid(tuple))
        retval = true;

    systable_endscan(sd);

    heap_close(pg_lo_meta, AccessShareLock);

    return retval;
}