Hi,
After commit 3e98c0bafb28de, we can display the usage of the
memory contexts using pg_backend_memory_contexts system
view.
However, its target is limited to the process attached to
the current session.
As discussed in the thread[1], it'll be useful to make it
possible to get the memory contexts of an arbitrary backend
process.
Attached PoC patch makes pg_get_backend_memory_contexts()
display meory contexts of the specified PID of the process.
=# -- PID of the target process is 17051
=# SELECT * FROM pg_get_backend_memory_contexts(17051) ;
name | ident | parent | level |
total_bytes | total_nblocks | free_bytes | free_chunks | used_bytes
-----------------------+-------+------------------+-------+-------------+---------------+------------+-------------+------------
TopMemoryContext | | | 0 |
68720 | 5 | 16816 | 16 | 51904
RowDescriptionContext | | TopMemoryContext | 1 |
8192 | 1 | 6880 | 0 | 1312
MessageContext | | TopMemoryContext | 1 |
65536 | 4 | 19912 | 1 | 45624
...
It doesn't display contexts of all the backends but only
the contexts of specified process.
I think it would be enough because I suppose this function
is used after investigations using ps command or other OS
level utilities.
The rough idea of implementation is like below:
1. send a signal to the specified process
2. signaled process dumps its memory contexts to a file
3. read the dumped file and display it to the user
Any thoughts?
[1]
https://www.postgresql.org/message-id/72a656e0f71d0860161e0b3f67e4d771%40oss.nttdata.com
Regards,
--
Atsushi Torikoshi
NTT DATA CORPORATION
From 7decfda337bbc422fece4c736a719b6fcfdc5cf3 Mon Sep 17 00:00:00 2001
From: Atsushi Torikoshi <torikos...@oss.nttdata.com>
Date: Mon, 31 Aug 2020 18:20:34 +0900
Subject: [PATCH] Enabled pg_get_backend_memory_contexts() to collect arbitrary
backend process's memory contexts.
Previously, pg_get_backend_memory_contexts() could only get the
memory contexts of the process which kicked it. This patch enables
to get memory contexts of the arbitrary process which PID is
specified by the argument.
---
doc/src/sgml/func.sgml | 13 +
src/backend/catalog/system_views.sql | 4 +-
src/backend/replication/basebackup.c | 3 +
src/backend/storage/ipc/procsignal.c | 4 +
src/backend/tcop/postgres.c | 5 +
src/backend/utils/adt/mcxtfuncs.c | 315 ++++++++++++++++++-
src/backend/utils/init/globals.c | 1 +
src/bin/initdb/initdb.c | 3 +-
src/bin/pg_basebackup/t/010_pg_basebackup.pl | 2 +-
src/bin/pg_rewind/filemap.c | 3 +
src/include/catalog/pg_proc.dat | 7 +-
src/include/miscadmin.h | 1 +
src/include/storage/procsignal.h | 1 +
src/include/utils/mcxtfuncs.h | 21 ++
src/test/regress/expected/rules.out | 2 +-
15 files changed, 364 insertions(+), 21 deletions(-)
create mode 100644 src/include/utils/mcxtfuncs.h
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index b9f591296a..cc9a458334 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21062,6 +21062,19 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
</para></entry>
</row>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_get_backend_memory_contexts</primary>
+ </indexterm>
+ <function>pg_get_backend_memory_contexts</function> ( <type>integer</type> )
+ <returnvalue>setof records</returnvalue>
+ </para>
+ <para>
+ Returns all the memory contexts of the specified process ID.
+ </para></entry>
+ </row>
+
<row>
<entry role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index a2d61302f9..88fb837ecd 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -555,10 +555,10 @@ REVOKE ALL ON pg_shmem_allocations FROM PUBLIC;
REVOKE EXECUTE ON FUNCTION pg_get_shmem_allocations() FROM PUBLIC;
CREATE VIEW pg_backend_memory_contexts AS
- SELECT * FROM pg_get_backend_memory_contexts();
+ SELECT * FROM pg_get_backend_memory_contexts(-1);
REVOKE ALL ON pg_backend_memory_contexts FROM PUBLIC;
-REVOKE EXECUTE ON FUNCTION pg_get_backend_memory_contexts() FROM PUBLIC;
+REVOKE EXECUTE ON FUNCTION pg_get_backend_memory_contexts FROM PUBLIC;
-- Statistics views
diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index 6064384e32..f69d851b6b 100644
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -184,6 +184,9 @@ static const char *const excludeDirContents[] =
/* Contents zeroed on startup, see StartupSUBTRANS(). */
"pg_subtrans",
+ /* Skip memory context dumped files. */
+ "pg_memusage",
+
/* end of list */
NULL
};
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 4fa385b0ec..5966729897 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -28,6 +28,7 @@
#include "storage/shmem.h"
#include "storage/sinval.h"
#include "tcop/tcopprot.h"
+#include "utils/mcxtfuncs.h"
/*
* The SIGUSR1 signal is multiplexed to support signaling multiple event
@@ -567,6 +568,9 @@ procsignal_sigusr1_handler(SIGNAL_ARGS)
if (CheckProcSignal(PROCSIG_BARRIER))
HandleProcSignalBarrierInterrupt();
+ if (CheckProcSignal(PROCSIG_DUMP_MEMORY))
+ HandleProcSignalDumpMemory();
+
if (CheckProcSignal(PROCSIG_RECOVERY_CONFLICT_DATABASE))
RecoveryConflictInterrupt(PROCSIG_RECOVERY_CONFLICT_DATABASE);
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index c9424f167c..d30426cf0f 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -76,6 +76,7 @@
#include "tcop/utility.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
+#include "utils/mcxtfuncs.h"
#include "utils/ps_status.h"
#include "utils/snapmgr.h"
#include "utils/timeout.h"
@@ -539,6 +540,10 @@ ProcessClientReadInterrupt(bool blocked)
/* Process notify interrupts, if any */
if (notifyInterruptPending)
ProcessNotifyInterrupt();
+
+ /* Process memory contexts dump interrupts, if any */
+ if (ProcSignalDumpMemoryPending)
+ ProcessDumpMemoryInterrupt();
}
else if (ProcDiePending)
{
diff --git a/src/backend/utils/adt/mcxtfuncs.c b/src/backend/utils/adt/mcxtfuncs.c
index 50e1b07ff0..12f7ecc116 100644
--- a/src/backend/utils/adt/mcxtfuncs.c
+++ b/src/backend/utils/adt/mcxtfuncs.c
@@ -15,34 +15,44 @@
#include "postgres.h"
+#include <unistd.h>
+
#include "funcapi.h"
#include "miscadmin.h"
#include "mb/pg_wchar.h"
+#include "storage/latch.h"
+#include "storage/procsignal.h"
#include "utils/builtins.h"
+#include "utils/mcxtfuncs.h"
/* ----------
* The max bytes for showing identifiers of MemoryContext.
* ----------
*/
-#define MEMORY_CONTEXT_IDENT_DISPLAY_SIZE 1024
+#define MEMORY_CONTEXT_DISPLAY_SIZE 1024
+
+#define PG_GET_BACKEND_MEMORY_CONTEXTS_COLS 9
/*
* PutMemoryContextsStatsTupleStore
* One recursion level for pg_get_backend_memory_contexts.
+ *
+ * Note: When fpout is not NULL, ferror() check must be done
+ * by the caller.
*/
static void
PutMemoryContextsStatsTupleStore(Tuplestorestate *tupstore,
TupleDesc tupdesc, MemoryContext context,
- const char *parent, int level)
+ const char *parent, int level, FILE *fpout)
{
-#define PG_GET_BACKEND_MEMORY_CONTEXTS_COLS 9
-
Datum values[PG_GET_BACKEND_MEMORY_CONTEXTS_COLS];
bool nulls[PG_GET_BACKEND_MEMORY_CONTEXTS_COLS];
+ char clipped_ident[MEMORY_CONTEXT_DISPLAY_SIZE];
MemoryContextCounters stat;
MemoryContext child;
const char *name;
const char *ident;
+ int idlen;
AssertArg(MemoryContextIsValid(context));
@@ -73,22 +83,23 @@ PutMemoryContextsStatsTupleStore(Tuplestorestate *tupstore,
if (ident)
{
- int idlen = strlen(ident);
- char clipped_ident[MEMORY_CONTEXT_IDENT_DISPLAY_SIZE];
-
+ idlen = strlen(ident);
/*
* Some identifiers such as SQL query string can be very long,
* truncate oversize identifiers.
*/
- if (idlen >= MEMORY_CONTEXT_IDENT_DISPLAY_SIZE)
- idlen = pg_mbcliplen(ident, idlen, MEMORY_CONTEXT_IDENT_DISPLAY_SIZE - 1);
+ if (idlen >= MEMORY_CONTEXT_DISPLAY_SIZE)
+ idlen = pg_mbcliplen(ident, idlen, MEMORY_CONTEXT_DISPLAY_SIZE - 1);
memcpy(clipped_ident, ident, idlen);
clipped_ident[idlen] = '\0';
values[1] = CStringGetTextDatum(clipped_ident);
}
else
+ {
+ idlen = 0;
nulls[1] = true;
+ }
if (parent)
values[2] = CStringGetTextDatum(parent);
@@ -101,12 +112,41 @@ PutMemoryContextsStatsTupleStore(Tuplestorestate *tupstore,
values[6] = Int64GetDatum(stat.freespace);
values[7] = Int64GetDatum(stat.freechunks);
values[8] = Int64GetDatum(stat.totalspace - stat.freespace);
- tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+
+ if(fpout == NULL)
+ /* pg_get_backend_memory_contexts() is called from local process */
+ tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+
+ else
+ {
+ int rc;
+ int parent_len = strlen(parent);
+ int name_len = strlen(name);
+
+ /*
+ * write out the current memory context information.
+ * Since some elements of values are reusable, we write it out.
+ */
+ fputc('D', fpout);
+ rc = fwrite(values, sizeof(values), 1, fpout);
+ rc = fwrite(nulls, sizeof(nulls), 1, fpout);
+
+ /* write out information which is not resuable from serialized values */
+ rc = fwrite(&name_len, sizeof(int), 1, fpout);
+ rc = fwrite(name, name_len, 1, fpout);
+ rc = fwrite(&idlen, sizeof(int), 1, fpout);
+ rc = fwrite(clipped_ident, idlen, 1, fpout);
+ rc = fwrite(&level, sizeof(int), 1, fpout);
+ rc = fwrite(&parent_len, sizeof(int), 1, fpout);
+ rc = fwrite(parent, parent_len, 1, fpout);
+ (void) rc; /* we'll check for error with ferror */
+
+ }
for (child = context->firstchild; child != NULL; child = child->nextchild)
{
PutMemoryContextsStatsTupleStore(tupstore, tupdesc,
- child, name, level + 1);
+ child, name, level + 1, fpout);
}
}
@@ -117,6 +157,8 @@ PutMemoryContextsStatsTupleStore(Tuplestorestate *tupstore,
Datum
pg_get_backend_memory_contexts(PG_FUNCTION_ARGS)
{
+ int pid = PG_GETARG_INT32(0);
+
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
TupleDesc tupdesc;
Tuplestorestate *tupstore;
@@ -147,11 +189,258 @@ pg_get_backend_memory_contexts(PG_FUNCTION_ARGS)
MemoryContextSwitchTo(oldcontext);
- PutMemoryContextsStatsTupleStore(tupstore, tupdesc,
- TopMemoryContext, NULL, 0);
+ if (pid == -1)
+ {
+ /*
+ * Since pid -1 indicates target is the local process, simply
+ * traverse memory contexts.
+ */
+ PutMemoryContextsStatsTupleStore(tupstore, tupdesc,
+ TopMemoryContext, "", 0, NULL);
+ }
+ else
+ {
+ /*
+ * Send signal for dumping memory contexts to the target process,
+ * and read the dumped file.
+ */
+ FILE *fpin;
+ char dumpfile[MAXPGPATH];
+
+ SendProcSignal(pid, PROCSIG_DUMP_MEMORY, InvalidBackendId);
+
+ snprintf(dumpfile, sizeof(dumpfile), "pg_memusage/%d", pid);
+
+ while (true)
+ {
+ CHECK_FOR_INTERRUPTS();
+
+ pg_usleep(10000L);
+
+ if ((fpin = AllocateFile(dumpfile, PG_BINARY_R)) == NULL)
+ {
+ if (errno != ENOENT)
+ ereport(LOG, (errcode_for_file_access(),
+ errmsg("could not open temporary memory dump file \"%s\": %m",
+ dumpfile)));
+ }
+ else
+ {
+ elog(DEBUG1, "Succeeded opening temporary memory dump file \"%s\": %m",
+ dumpfile);
+ break;
+ }
+ }
+
+ /* read dumped files */
+ while (true)
+ {
+ Datum values[PG_GET_BACKEND_MEMORY_CONTEXTS_COLS];
+ bool nulls[PG_GET_BACKEND_MEMORY_CONTEXTS_COLS];
+ char name[MEMORY_CONTEXT_DISPLAY_SIZE];
+ char parent[MEMORY_CONTEXT_DISPLAY_SIZE];
+ char clipped_ident[MEMORY_CONTEXT_DISPLAY_SIZE];
+ int level;
+ int name_len;
+ int parent_len;
+ int idlen;
+
+ memset(values, 0, sizeof(values));
+ memset(nulls, 0, sizeof(nulls));
+
+ switch (fgetc(fpin))
+ {
+ /* 'D' A memory context information follows. */
+ case 'D':
+ if (fread(values, 1, sizeof(values), fpin) != sizeof(values))
+ {
+ ereport(WARNING,
+ (errmsg("corrupted memory dump file \"%s\"",
+ dumpfile)));
+ goto done;
+ }
+ if (fread(nulls, 1, sizeof(nulls), fpin) != sizeof(nulls))
+ {
+ ereport(WARNING,
+ (errmsg("corrupted memory dump file \"%s\"",
+ dumpfile)));
+ goto done;
+ }
+ if (fread(&name_len, 1, sizeof(int), fpin) != sizeof(int))
+ {
+ ereport(WARNING,
+ (errmsg("corrupted memory dump file \"%s\"",
+ dumpfile)));
+ goto done;
+ }
+ if (fread(name, 1, name_len, fpin) != name_len)
+ {
+ ereport(WARNING,
+ (errmsg("corrupted memory dump file \"%s\"",
+ dumpfile)));
+ goto done;
+ }
+ name[name_len] = '\0';
+ if (fread(&idlen, 1, sizeof(int), fpin) != sizeof(int))
+ {
+ ereport(WARNING,
+ (errmsg("corrupted memory dump file \"%s\"",
+ dumpfile)));
+ goto done;
+ }
+ if (fread(clipped_ident, 1, idlen, fpin) != idlen)
+ {
+ ereport(WARNING,
+ (errmsg("corrupted memory dump file \"%s\"",
+ dumpfile)));
+ goto done;
+ }
+ clipped_ident[idlen] = '\0';
+ if (fread(&level, 1, sizeof(int), fpin) != sizeof(int))
+ {
+ ereport(WARNING,
+ (errmsg("corrupted memory dump file \"%s\"",
+ dumpfile)));
+ goto done;
+ }
+ if (fread(&parent_len, 1, sizeof(int), fpin) != sizeof(int))
+ {
+ ereport(WARNING,
+ (errmsg("corrupted memory dump file \"%s\"",
+ dumpfile)));
+ goto done;
+ }
+ if (fread(parent, 1, parent_len, fpin) != parent_len)
+ {
+ ereport(WARNING,
+ (errmsg("corrupted memory dump file \"%s\"",
+ dumpfile)));
+ goto done;
+ }
+ parent[parent_len] = '\0';
+
+ /*
+ * Overwrite some elements of values which are not available
+ * from serialized values.
+ */
+ if (!nulls[0])
+ values[0] = CStringGetTextDatum(name);
+
+ if (!nulls[1])
+ values[1] = CStringGetTextDatum(clipped_ident);
+
+ if (!nulls[2])
+ values[2] = CStringGetTextDatum(parent);
+
+ tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+ break;
+
+ case 'E':
+ goto done;
+
+ default:
+ ereport(WARNING,
+ (errmsg("corrupted memory dump file \"%s\"",
+ dumpfile)));
+ goto done;
+ }
+ }
+done:
+ FreeFile(fpin);
+ unlink(dumpfile);
+ }
/* clean up and return the tuplestore */
tuplestore_donestoring(tupstore);
return (Datum) 0;
}
+
+/*
+ * dump_memory_contexts
+ * Dumping local memory contexts to a file.
+ * This function does not delete the file as it is intended to be read by
+ * another process.
+ */
+static void
+dump_memory_contexts(void)
+{
+ FILE *fpout;
+ char tmpfile[MAXPGPATH];
+ char dumpfile[MAXPGPATH];
+
+ snprintf(tmpfile, sizeof(tmpfile), "pg_memusage/%d.tmp", MyProcPid);
+ snprintf(dumpfile, sizeof(dumpfile), "pg_memusage/%d", MyProcPid);
+
+ /*
+ * Open a temp file to dump the current memory context.
+ */
+ fpout = AllocateFile(tmpfile, PG_BINARY_W);
+ if (fpout == NULL)
+ {
+ ereport(LOG,
+ (errcode_for_file_access(),
+ errmsg("could not write temporary memory context file \"%s\": %m",
+ tmpfile)));
+ return;
+ }
+
+ PutMemoryContextsStatsTupleStore(NULL, NULL,
+ TopMemoryContext, "", 0, fpout);
+
+ /* No more output to be done. */
+ fputc('E', fpout);
+
+ if (ferror(fpout))
+ {
+ ereport(LOG,
+ (errcode_for_file_access(),
+ errmsg("could not write temporary memory context dump file \"%s\": %m",
+ tmpfile)));
+ FreeFile(fpout);
+ unlink(tmpfile);
+ }
+ else if (FreeFile(fpout) < 0)
+ {
+ ereport(LOG,
+ (errcode_for_file_access(),
+ errmsg("could not close temporary memory context file \"%s\": %m",
+ tmpfile)));
+ unlink(tmpfile);
+ }
+ else if (rename(tmpfile, dumpfile) < 0)
+ {
+ ereport(LOG,
+ (errcode_for_file_access(),
+ errmsg("could not rename dump file \"%s\" to \"%s\": %m",
+ tmpfile, dumpfile)));
+ unlink(tmpfile);
+ }
+}
+
+/*
+ * ProcessDumpMemoryInterrupt
+ *
+ * The portion of memory dump interrupt handling that runs
+ * outside of the signal handler.
+ */
+void
+ProcessDumpMemoryInterrupt(void)
+{
+ ProcSignalDumpMemoryPending = false;
+ dump_memory_contexts();
+}
+
+/*
+ * Handle receipt of an interrupt indicating a dump memory context.
+ *
+ * Signal handler portion of interrupt handling.
+ */
+void
+HandleProcSignalDumpMemory(void)
+{
+ ProcSignalDumpMemoryPending = true;
+
+ /* make sure the event is processed in due course */
+ SetLatch(MyLatch);
+}
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 6ab8216839..463337f661 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -33,6 +33,7 @@ volatile sig_atomic_t ProcDiePending = false;
volatile sig_atomic_t ClientConnectionLost = false;
volatile sig_atomic_t IdleInTransactionSessionTimeoutPending = false;
volatile sig_atomic_t ProcSignalBarrierPending = false;
+volatile sig_atomic_t ProcSignalDumpMemoryPending = false;
volatile uint32 InterruptHoldoffCount = 0;
volatile uint32 QueryCancelHoldoffCount = 0;
volatile uint32 CritSectionCount = 0;
diff --git a/src/bin/initdb/initdb.c b/src/bin/initdb/initdb.c
index 786672b1b6..c3130dc6f9 100644
--- a/src/bin/initdb/initdb.c
+++ b/src/bin/initdb/initdb.c
@@ -220,7 +220,8 @@ static const char *const subdirs[] = {
"pg_xact",
"pg_logical",
"pg_logical/snapshots",
- "pg_logical/mappings"
+ "pg_logical/mappings",
+ "pg_memusage"
};
diff --git a/src/bin/pg_basebackup/t/010_pg_basebackup.pl b/src/bin/pg_basebackup/t/010_pg_basebackup.pl
index f674a7c94e..683c2d5408 100644
--- a/src/bin/pg_basebackup/t/010_pg_basebackup.pl
+++ b/src/bin/pg_basebackup/t/010_pg_basebackup.pl
@@ -124,7 +124,7 @@ is_deeply(
# Contents of these directories should not be copied.
foreach my $dirname (
- qw(pg_dynshmem pg_notify pg_replslot pg_serial pg_snapshots pg_stat_tmp pg_subtrans)
+ qw(pg_dynshmem pg_notify pg_replslot pg_serial pg_snapshots pg_stat_tmp pg_subtrans pg_memusage)
)
{
is_deeply(
diff --git a/src/bin/pg_rewind/filemap.c b/src/bin/pg_rewind/filemap.c
index 1879257b66..23471007d8 100644
--- a/src/bin/pg_rewind/filemap.c
+++ b/src/bin/pg_rewind/filemap.c
@@ -85,6 +85,9 @@ static const char *excludeDirContents[] =
/* Contents zeroed on startup, see StartupSUBTRANS(). */
"pg_subtrans",
+ /* Skip memory context dumped files. */
+ "pg_memusage",
+
/* end of list */
NULL
};
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 1dd325e0e6..b6859b23e8 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -7812,9 +7812,10 @@
{ oid => '2282', descr => 'information about all memory contexts of local backend',
proname => 'pg_get_backend_memory_contexts', prorows => '100', proretset => 't',
provolatile => 'v', proparallel => 'r', prorettype => 'record', proargtypes => '',
- proallargtypes => '{text,text,text,int4,int8,int8,int8,int8,int8}',
- proargmodes => '{o,o,o,o,o,o,o,o,o}',
- proargnames => '{name, ident, parent, level, total_bytes, total_nblocks, free_bytes, free_chunks, used_bytes}',
+ provolatile => 'v', proparallel => 'r', prorettype => 'record', proargtypes => 'int4',
+ proallargtypes => '{int4,text,text,text,int4,int8,int8,int8,int8,int8}',
+ proargmodes => '{i,o,o,o,o,o,o,o,o,o}',
+ proargnames => '{pid, name, ident, parent, level, total_bytes, total_nblocks, free_bytes, free_chunks, used_bytes}',
prosrc => 'pg_get_backend_memory_contexts' },
# non-persistent series generator
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 72e3352398..812032bb15 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -83,6 +83,7 @@ extern PGDLLIMPORT volatile sig_atomic_t QueryCancelPending;
extern PGDLLIMPORT volatile sig_atomic_t ProcDiePending;
extern PGDLLIMPORT volatile sig_atomic_t IdleInTransactionSessionTimeoutPending;
extern PGDLLIMPORT volatile sig_atomic_t ProcSignalBarrierPending;
+extern PGDLLIMPORT volatile sig_atomic_t ProcSignalDumpMemoryPending;
extern PGDLLIMPORT volatile sig_atomic_t ClientConnectionLost;
diff --git a/src/include/storage/procsignal.h b/src/include/storage/procsignal.h
index 5cb39697f3..5db92a9a52 100644
--- a/src/include/storage/procsignal.h
+++ b/src/include/storage/procsignal.h
@@ -34,6 +34,7 @@ typedef enum
PROCSIG_PARALLEL_MESSAGE, /* message from cooperating parallel backend */
PROCSIG_WALSND_INIT_STOPPING, /* ask walsenders to prepare for shutdown */
PROCSIG_BARRIER, /* global barrier interrupt */
+ PROCSIG_DUMP_MEMORY, /* request dumping memory context interrupt */
/* Recovery conflict reasons */
PROCSIG_RECOVERY_CONFLICT_DATABASE,
diff --git a/src/include/utils/mcxtfuncs.h b/src/include/utils/mcxtfuncs.h
new file mode 100644
index 0000000000..cd74bb6700
--- /dev/null
+++ b/src/include/utils/mcxtfuncs.h
@@ -0,0 +1,21 @@
+/*-------------------------------------------------------------------------
+ *
+ * mcxtfuncs.h
+ * Declarations for showing backend memory context.
+ *
+ * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ * src/backend/utils/adt/mcxtfuncs.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef MCXT_H
+#define MCXT_H
+
+extern void ProcessDumpMemoryInterrupt(void);
+extern void HandleProcSignalDumpMemory(void);
+
+#endif /* MCXT_H */
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index 2a18dc423e..990b54d777 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1333,7 +1333,7 @@ pg_backend_memory_contexts| SELECT pg_get_backend_memory_contexts.name,
pg_get_backend_memory_contexts.free_bytes,
pg_get_backend_memory_contexts.free_chunks,
pg_get_backend_memory_contexts.used_bytes
- FROM pg_get_backend_memory_contexts() pg_get_backend_memory_contexts(name, ident, parent, level, total_bytes, total_nblocks, free_bytes, free_chunks, used_bytes);
+ FROM pg_get_backend_memory_contexts('-1'::integer) pg_get_backend_memory_contexts(name, ident, parent, level, total_bytes, total_nblocks, free_bytes, free_chunks, used_bytes);
pg_config| SELECT pg_config.name,
pg_config.setting
FROM pg_config() pg_config(name, setting);
--
2.18.1
