sortsupport.c File Reference

#include "postgres.h"
#include "fmgr.h"
#include "utils/lsyscache.h"
#include "utils/sortsupport.h"

Include dependency graph for sortsupport.c:

Go to the source code of this file.

Data Structures
struct	SortShimExtra
Defines
#define	SORTSUPPORT_INCLUDE_DEFINITIONS
Functions
static int	comparison_shim (Datum x, Datum y, SortSupport ssup)
void	PrepareSortSupportComparisonShim (Oid cmpFunc, SortSupport ssup)
void	PrepareSortSupportFromOrderingOp (Oid orderingOp, SortSupport ssup)

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Define Documentation

#define SORTSUPPORT_INCLUDE_DEFINITIONS

Definition at line 19 of file sortsupport.c.

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Function Documentation

static int comparison_shim	(	Datum	x,
		Datum	y,
		SortSupport	ssup
	)			[static]

Definition at line 42 of file sortsupport.c.

References FunctionCallInfoData::arg, elog, ERROR, SortShimExtra::fcinfo, SortShimExtra::flinfo, FmgrInfo::fn_oid, FunctionCallInvoke, FunctionCallInfoData::isnull, and SortSupportData::ssup_extra.

{
    SortShimExtra *extra = (SortShimExtra *) ssup->ssup_extra;
    Datum       result;

    extra->fcinfo.arg[0] = x;
    extra->fcinfo.arg[1] = y;

    /* just for paranoia's sake, we reset isnull each time */
    extra->fcinfo.isnull = false;

    result = FunctionCallInvoke(&extra->fcinfo);

    /* Check for null result, since caller is clearly not expecting one */
    if (extra->fcinfo.isnull)
        elog(ERROR, "function %u returned NULL", extra->flinfo.fn_oid);

    return result;
}

void PrepareSortSupportComparisonShim	(	Oid	cmpFunc,
		SortSupport	ssup
	)

Definition at line 67 of file sortsupport.c.

References FunctionCallInfoData::argnull, SortSupportData::comparator, SortShimExtra::fcinfo, SortShimExtra::flinfo, fmgr_info_cxt(), InitFunctionCallInfoData, MemoryContextAlloc(), NULL, SortSupportData::ssup_collation, SortSupportData::ssup_cxt, and SortSupportData::ssup_extra.

Referenced by MJExamineQuals(), and PrepareSortSupportFromOrderingOp().

{
    SortShimExtra *extra;

    extra = (SortShimExtra *) MemoryContextAlloc(ssup->ssup_cxt,
                                                 sizeof(SortShimExtra));

    /* Lookup the comparison function */
    fmgr_info_cxt(cmpFunc, &extra->flinfo, ssup->ssup_cxt);

    /* We can initialize the callinfo just once and re-use it */
    InitFunctionCallInfoData(extra->fcinfo, &extra->flinfo, 2,
                             ssup->ssup_collation, NULL, NULL);
    extra->fcinfo.argnull[0] = false;
    extra->fcinfo.argnull[1] = false;

    ssup->ssup_extra = extra;
    ssup->comparator = comparison_shim;
}

void PrepareSortSupportFromOrderingOp	(	Oid	orderingOp,
		SortSupport	ssup
	)

Definition at line 95 of file sortsupport.c.

References Assert, SortSupportData::comparator, elog, ERROR, get_sort_function_for_ordering_op(), NULL, OidFunctionCall1, PointerGetDatum, PrepareSortSupportComparisonShim(), and SortSupportData::ssup_reverse.

Referenced by compute_scalar_stats(), ExecInitMergeAppend(), tuplesort_begin_datum(), and tuplesort_begin_heap().

{
    Oid         sortFunction;
    bool        issupport;

    if (!get_sort_function_for_ordering_op(orderingOp,
                                           &sortFunction,
                                           &issupport,
                                           &ssup->ssup_reverse))
        elog(ERROR, "operator %u is not a valid ordering operator",
             orderingOp);

    if (issupport)
    {
        /* The sort support function should provide a comparator */
        OidFunctionCall1(sortFunction, PointerGetDatum(ssup));
        Assert(ssup->comparator != NULL);
    }
    else
    {
        /* We'll use a shim to call the old-style btree comparator */
        PrepareSortSupportComparisonShim(sortFunction, ssup);
    }
}