From 125bf342fd98b2b1deef20bcf3028e4dda0445fb Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 1 Oct 2004 21:03:42 +0000
Subject: [PATCH] =?UTF-8?q?Convert=20pg=5Fstat=5Fget=5Fbackend=5Fidset=20t?=
=?UTF-8?q?o=20use=20the=20existing=20SRF=20support.=20This=20seems=20the?=
=?UTF-8?q?=20cleanest=20way=20of=20fixing=20its=20lack=20of=20a=20shutdow?=
=?UTF-8?q?n=20callback,=20which=20was=20preventing=20it=20from=20working?=
=?UTF-8?q?=20correctly=20in=20a=20query=20that=20didn't=20run=20it=20to?=
=?UTF-8?q?=20completion.=20=20Per=20bug=20report=20from=20Szima=20G=C3=84?=
=?UTF-8?q?bor.?=
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---
src/backend/utils/adt/pgstatfuncs.c | 74 ++++++++++++++++++-----------
1 file changed, 45 insertions(+), 29 deletions(-)
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 03166eac482..f648b0c1cd2 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -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,
- 2 * sizeof(int));
- ((int *) (fmgr_info->fn_extra))[0] = 0;
- ((int *) (fmgr_info->fn_extra))[1] = pgstat_fetch_stat_numbackends();
+ fctx = MemoryContextAlloc(funcctx->multi_call_memory_ctx,
+ 2 * sizeof(int));
+ 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;
+
+ fctx[0] += 1;
+ result = fctx[0];
- if (result > ((int *) (fmgr_info->fn_extra))[1])
+ 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);
}
--
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