Fix catalog data of pg_stop_backup(), labelled v2

This function has been incorrectly marked as a set-returning function
with prorows (estimated number of rows) set to 1 since its creation in
7117685, that introduced non-exclusive backups.  There is no need for
that as the function is designed to return only one tuple.

This commit fixes the catalog definition of pg_stop_backup_v2() so as it
is not marked as proretset anymore, with prorows set to 0.  This
simplifies its internals by removing one tuplestore (used for one single
record anyway) and by removing all the checks related to a set-returning
function.

Issue found during my quest to simplify some of the logic used in
in-core system functions.

Bump catalog version.

Reviewed-by: Aleksander Alekseev, Kyotaro Horiguchi
Discussion: https://postgr.es/m/Yh8guT78f1Ercfzw@paquier.xyz

diff --git a/src/backend/access/transam/xlogfuncs.c b/src/backend/access/transam/xlogfuncs.c
index 12e2bf4135d52af1bb9c85b225b0ca18649ac181..2752be63c10a431d9015921663cb59c97953ec21 100644 (file)
--- a/src/backend/access/transam/xlogfuncs.c
+++ b/src/backend/access/transam/xlogfuncs.c
@@ -165,43 +165,20 @@ pg_stop_backup(PG_FUNCTION_ARGS)
 Datum
 pg_stop_backup_v2(PG_FUNCTION_ARGS)
 {
-       ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+#define PG_STOP_BACKUP_V2_COLS 3
        TupleDesc       tupdesc;
-       Tuplestorestate *tupstore;
-       MemoryContext per_query_ctx;
-       MemoryContext oldcontext;
-       Datum           values[3];
-       bool            nulls[3];
+       Datum           values[PG_STOP_BACKUP_V2_COLS];
+       bool            nulls[PG_STOP_BACKUP_V2_COLS];
 
        bool            exclusive = PG_GETARG_BOOL(0);
        bool            waitforarchive = PG_GETARG_BOOL(1);
        XLogRecPtr      stoppoint;
        SessionBackupState status = get_backup_status();
 
-       /* check to see if caller supports us returning a tuplestore */
-       if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-               ereport(ERROR,
-                               (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-                                errmsg("set-valued function called in context that cannot accept a set")));
-       if (!(rsinfo->allowedModes & SFRM_Materialize))
-               ereport(ERROR,
-                               (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-                                errmsg("materialize mode required, but it is not allowed in this context")));
-
-       /* Build a tuple descriptor for our result type */
+       /* Initialize attributes information in the tuple descriptor */
        if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
                elog(ERROR, "return type must be a row type");
 
-       per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-       oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
-       tupstore = tuplestore_begin_heap(true, false, work_mem);
-       rsinfo->returnMode = SFRM_Materialize;
-       rsinfo->setResult = tupstore;
-       rsinfo->setDesc = tupdesc;
-
-       MemoryContextSwitchTo(oldcontext);
-
        MemSet(values, 0, sizeof(values));
        MemSet(nulls, 0, sizeof(nulls));
 
@@ -251,9 +228,8 @@ pg_stop_backup_v2(PG_FUNCTION_ARGS)
        /* Stoppoint is included on both exclusive and nonexclusive backups */
        values[0] = LSNGetDatum(stoppoint);
 
-       tuplestore_putvalues(tupstore, tupdesc, values, nulls);
-
-       return (Datum) 0;
+       /* Returns the record as Datum */
+       PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
 }
 
 /*

diff --git a/src/backend/catalog/system_functions.sql b/src/backend/catalog/system_functions.sql
index 758ab6e25a33dac594a1ab7529c74e4285b00f82..81bac6f5812dcbe5da25c8326a64bcb01f218aba 100644 (file)
--- a/src/backend/catalog/system_functions.sql
+++ b/src/backend/catalog/system_functions.sql
@@ -384,7 +384,7 @@ CREATE OR REPLACE FUNCTION
 CREATE OR REPLACE FUNCTION pg_stop_backup (
         exclusive boolean, wait_for_archive boolean DEFAULT true,
         OUT lsn pg_lsn, OUT labelfile text, OUT spcmapfile text)
-  RETURNS SETOF record STRICT VOLATILE LANGUAGE internal as 'pg_stop_backup_v2'
+  RETURNS record STRICT VOLATILE LANGUAGE internal as 'pg_stop_backup_v2'
   PARALLEL RESTRICTED;
 
 CREATE OR REPLACE FUNCTION

diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index 5cf18059b82b825a99b11947511fc680deff4c61..695990959e5db1bbec5089cdf07d6f71ed0aa0aa 100644 (file)
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -53,6 +53,6 @@
  */
 
 /*                                                     yyyymmddN */
-#define CATALOG_VERSION_NO     202203011
+#define CATALOG_VERSION_NO     202203031
 
 #endif

diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index bf8885817161f500f53011ccca777dd178ae2384..d8e8715ed1c00068a4c4350353d6382ccae8cd3b 100644 (file)
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6275,9 +6275,9 @@
   proname => 'pg_stop_backup', provolatile => 'v', proparallel => 'r',
   prorettype => 'pg_lsn', proargtypes => '', prosrc => 'pg_stop_backup' },
 { oid => '2739', descr => 'finish taking an online backup',
-  proname => 'pg_stop_backup', prorows => '1', proretset => 't',
-  provolatile => 'v', proparallel => 'r', prorettype => 'record',
-  proargtypes => 'bool bool', proallargtypes => '{bool,bool,pg_lsn,text,text}',
+  proname => 'pg_stop_backup', provolatile => 'v', proparallel => 'r',
+  prorettype => 'record', proargtypes => 'bool bool',
+  proallargtypes => '{bool,bool,pg_lsn,text,text}',
   proargmodes => '{i,i,o,o,o}',
   proargnames => '{exclusive,wait_for_archive,lsn,labelfile,spcmapfile}',
   prosrc => 'pg_stop_backup_v2' },