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Convert pg_stat_get_backend_idset to use the existing SRF support.

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This seems the cleanest way of fixing its lack of a shutdown callback,
which was preventing it from working correctly in a query that didn't
run it to completion.  Per bug report from Szima GÄbor.
This commit is contained in:
Tom Lane 2004-10-01 21:03:42 +00:00
parent b62aa83f0e
commit 125bf342fd
1 changed files with 45 additions and 29 deletions
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72
src/backend/utils/adt/pgstatfuncs.c
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@ -1,14 +1,29 @@
/*-------------------------------------------------------------------------
*
* pgstatfuncs.c
* Functions for accessing the statistics collector data
*
* Portions Copyright (c) 1996-2004, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/pgstatfuncs.c,v 1.19 2004/10/01 21:03:42 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "fmgr.h"
#include "miscadmin.h"
#include "utils/hsearch.h"
#include "access/xact.h"
#include "catalog/pg_shadow.h"
#include "fmgr.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "nodes/execnodes.h"
#include "pgstat.h"
#include "utils/hsearch.h"
/* bogus ... these externs should be in a header file */
extern Datum pg_stat_get_numscans(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_tuples_returned(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_tuples_fetched(PG_FUNCTION_ARGS);
@ -181,40 +196,41 @@ pg_stat_get_blocks_hit(PG_FUNCTION_ARGS)
Datum
pg_stat_get_backend_idset(PG_FUNCTION_ARGS)
{
FmgrInfo *fmgr_info = fcinfo->flinfo;
FuncCallContext *funcctx;
int *fctx;
int32 result;
if (fcinfo->resultinfo == NULL ||
!IsA(fcinfo->resultinfo, ReturnSetInfo))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("set-valued function called in context that "
"cannot accept a set")));
if (fmgr_info->fn_extra == NULL)
/* stuff done only on the first call of the function */
if (SRF_IS_FIRSTCALL())
{
if (fmgr_info->fn_mcxt == NULL)
elog(ERROR, "no function memory context in set-function");
/* create a function context for cross-call persistence */
funcctx = SRF_FIRSTCALL_INIT();
fmgr_info->fn_extra = MemoryContextAlloc(fmgr_info->fn_mcxt,
fctx = MemoryContextAlloc(funcctx->multi_call_memory_ctx,
2 * sizeof(int));
((int *) (fmgr_info->fn_extra))[0] = 0;
((int *) (fmgr_info->fn_extra))[1] = pgstat_fetch_stat_numbackends();
funcctx->user_fctx = fctx;
fctx[0] = 0;
fctx[1] = pgstat_fetch_stat_numbackends();
}
((int *) (fmgr_info->fn_extra))[0] += 1;
result = ((int *) (fmgr_info->fn_extra))[0];
/* stuff done on every call of the function */
funcctx = SRF_PERCALL_SETUP();
fctx = funcctx->user_fctx;
if (result > ((int *) (fmgr_info->fn_extra))[1])
fctx[0] += 1;
result = fctx[0];
if (result <= fctx[1])
{
pfree(fmgr_info->fn_extra);
fmgr_info->fn_extra = NULL;
((ReturnSetInfo *) (fcinfo->resultinfo))->isDone = ExprEndResult;
PG_RETURN_NULL();
/* do when there is more left to send */
SRF_RETURN_NEXT(funcctx, Int32GetDatum(result));
}
else
{
/* do when there is no more left */
SRF_RETURN_DONE(funcctx);
}
((ReturnSetInfo *) (fcinfo->resultinfo))->isDone = ExprMultipleResult;
PG_RETURN_INT32(result);
}