Move SQL-callable code related to multixacts into its own file

A patch is under discussion to add more SQL capabilities related to
multixacts, and this move avoids bloating the file more than necessary.
This affects pg_get_multixact_members().  A side effect of this move is
the requirement to add mxstatus_to_string() to multixact.h.

Extracted from a larger patch by the same author, tweaked by me.

Author: Naga Appani <nagnrik@gmail.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Discussion: https://postgr.es/m/CA+QeY+AAsYK6WvBW4qYzHz4bahHycDAY_q5ECmHkEV_eB9ckzg@mail.gmail.com

diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c
index 3cb09c3d5987c2b0a45cc848c2c312d590cb2713..886740d2d553466c1094060b8f5d53fe5079da2b 100644 (file)
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -398,8 +398,6 @@ static int  mXactCacheGetById(MultiXactId multi, MultiXactMember **members);
 static void mXactCachePut(MultiXactId multi, int nmembers,
                                                  MultiXactMember *members);
 
-static char *mxstatus_to_string(MultiXactStatus status);
-
 /* management of SLRU infrastructure */
 static bool MultiXactOffsetPagePrecedes(int64 page1, int64 page2);
 static bool MultiXactMemberPagePrecedes(int64 page1, int64 page2);
@@ -1747,7 +1745,7 @@ mXactCachePut(MultiXactId multi, int nmembers, MultiXactMember *members)
        }
 }
 
-static char *
+char *
 mxstatus_to_string(MultiXactStatus status)
 {
        switch (status)
@@ -3414,68 +3412,6 @@ multixact_redo(XLogReaderState *record)
                elog(PANIC, "multixact_redo: unknown op code %u", info);
 }
 
-Datum
-pg_get_multixact_members(PG_FUNCTION_ARGS)
-{
-       typedef struct
-       {
-               MultiXactMember *members;
-               int                     nmembers;
-               int                     iter;
-       } mxact;
-       MultiXactId mxid = PG_GETARG_TRANSACTIONID(0);
-       mxact      *multi;
-       FuncCallContext *funccxt;
-
-       if (mxid < FirstMultiXactId)
-               ereport(ERROR,
-                               (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-                                errmsg("invalid MultiXactId: %u", mxid)));
-
-       if (SRF_IS_FIRSTCALL())
-       {
-               MemoryContext oldcxt;
-               TupleDesc       tupdesc;
-
-               funccxt = SRF_FIRSTCALL_INIT();
-               oldcxt = MemoryContextSwitchTo(funccxt->multi_call_memory_ctx);
-
-               multi = palloc(sizeof(mxact));
-               /* no need to allow for old values here */
-               multi->nmembers = GetMultiXactIdMembers(mxid, &multi->members, false,
-                                                                                               false);
-               multi->iter = 0;
-
-               if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-                       elog(ERROR, "return type must be a row type");
-               funccxt->tuple_desc = tupdesc;
-               funccxt->attinmeta = TupleDescGetAttInMetadata(tupdesc);
-               funccxt->user_fctx = multi;
-
-               MemoryContextSwitchTo(oldcxt);
-       }
-
-       funccxt = SRF_PERCALL_SETUP();
-       multi = (mxact *) funccxt->user_fctx;
-
-       while (multi->iter < multi->nmembers)
-       {
-               HeapTuple       tuple;
-               char       *values[2];
-
-               values[0] = psprintf("%u", multi->members[multi->iter].xid);
-               values[1] = mxstatus_to_string(multi->members[multi->iter].status);
-
-               tuple = BuildTupleFromCStrings(funccxt->attinmeta, values);
-
-               multi->iter++;
-               pfree(values[0]);
-               SRF_RETURN_NEXT(funccxt, HeapTupleGetDatum(tuple));
-       }
-
-       SRF_RETURN_DONE(funccxt);
-}
-
 /*
  * Entrypoint for sync.c to sync offsets files.
  */

diff --git a/src/backend/utils/adt/Makefile b/src/backend/utils/adt/Makefile
index ffeacf2b819f32edd10da1023aef9bf38dd538ce..cc68ac545a5f0f918a1fe4363bbf0d81eff60a75 100644 (file)
--- a/src/backend/utils/adt/Makefile
+++ b/src/backend/utils/adt/Makefile
@@ -68,6 +68,7 @@ OBJS = \
        misc.o \
        multirangetypes.o \
        multirangetypes_selfuncs.o \
+       multixactfuncs.o \
        name.o \
        network.o \
        network_gist.o \

diff --git a/src/backend/utils/adt/meson.build b/src/backend/utils/adt/meson.build
index ed9bbd7b9266bf69b6b818fe22a0bc79b2adb655..dac372c3bea3bc970ee002198eaa7765ebebed9c 100644 (file)
--- a/src/backend/utils/adt/meson.build
+++ b/src/backend/utils/adt/meson.build
@@ -55,6 +55,7 @@ backend_sources += files(
   'misc.c',
   'multirangetypes.c',
   'multirangetypes_selfuncs.c',
+  'multixactfuncs.c',
   'name.c',
   'network.c',
   'network_gist.c',

diff --git a/src/backend/utils/adt/multixactfuncs.c b/src/backend/utils/adt/multixactfuncs.c
new file mode 100644 (file)
index 0000000..e74ea93
--- /dev/null
+++ b/src/backend/utils/adt/multixactfuncs.c
@@ -0,0 +1,87 @@
+/*-------------------------------------------------------------------------
+ *
+ * multixactfuncs.c
+ *       Functions for accessing multixact-related data.
+ *
+ * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *       src/backend/utils/adt/multixactfuncs.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/multixact.h"
+#include "funcapi.h"
+#include "utils/builtins.h"
+
+/*
+ * pg_get_multixact_members
+ *
+ * Returns information about the MultiXactMembers of the specified
+ * MultiXactId.
+ */
+Datum
+pg_get_multixact_members(PG_FUNCTION_ARGS)
+{
+       typedef struct
+       {
+               MultiXactMember *members;
+               int                     nmembers;
+               int                     iter;
+       } mxact;
+       MultiXactId mxid = PG_GETARG_TRANSACTIONID(0);
+       mxact      *multi;
+       FuncCallContext *funccxt;
+
+       if (mxid < FirstMultiXactId)
+               ereport(ERROR,
+                               (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+                                errmsg("invalid MultiXactId: %u", mxid)));
+
+       if (SRF_IS_FIRSTCALL())
+       {
+               MemoryContext oldcxt;
+               TupleDesc       tupdesc;
+
+               funccxt = SRF_FIRSTCALL_INIT();
+               oldcxt = MemoryContextSwitchTo(funccxt->multi_call_memory_ctx);
+
+               multi = palloc(sizeof(mxact));
+               /* no need to allow for old values here */
+               multi->nmembers = GetMultiXactIdMembers(mxid, &multi->members, false,
+                                                                                               false);
+               multi->iter = 0;
+
+               if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+                       elog(ERROR, "return type must be a row type");
+               funccxt->tuple_desc = tupdesc;
+               funccxt->attinmeta = TupleDescGetAttInMetadata(tupdesc);
+               funccxt->user_fctx = multi;
+
+               MemoryContextSwitchTo(oldcxt);
+       }
+
+       funccxt = SRF_PERCALL_SETUP();
+       multi = (mxact *) funccxt->user_fctx;
+
+       while (multi->iter < multi->nmembers)
+       {
+               HeapTuple       tuple;
+               char       *values[2];
+
+               values[0] = psprintf("%u", multi->members[multi->iter].xid);
+               values[1] = mxstatus_to_string(multi->members[multi->iter].status);
+
+               tuple = BuildTupleFromCStrings(funccxt->attinmeta, values);
+
+               multi->iter++;
+               pfree(values[0]);
+               SRF_RETURN_NEXT(funccxt, HeapTupleGetDatum(tuple));
+       }
+
+       SRF_RETURN_DONE(funccxt);
+}

diff --git a/src/include/access/multixact.h b/src/include/access/multixact.h
index b876e98f46ed744c87105e8e5289275f936a471e..6607b645a1820fa3ca645cc5d1684904f57d8328 100644 (file)
--- a/src/include/access/multixact.h
+++ b/src/include/access/multixact.h
@@ -158,5 +158,6 @@ extern void multixact_desc(StringInfo buf, XLogReaderState *record);
 extern const char *multixact_identify(uint8 info);
 extern char *mxid_to_string(MultiXactId multi, int nmembers,
                                                        MultiXactMember *members);
+extern char *mxstatus_to_string(MultiXactStatus status);
 
 #endif                                                 /* MULTIXACT_H */