On 5/30/17 23:10, Peter Eisentraut wrote:
> Here is a proposed solution that splits bgw_name into bgw_type and
> bgw_name_extra. bgw_type shows up in pg_stat_activity.backend_type.
> Uses of application_name are removed, because they are no longer
> necessary to identity the process type.
Updated patch incorporating the feedback. I have kept bgw_name as it
was and just added bgw_type completely independently.
One open question is how to treat a missing (empty) bgw_type. I
currently fill in bgw_name as a fallback. We could also treat it as an
error or a warning as a transition measure.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
From 73142adf6e56e44d97bd9f855072cba17ef5ea4c Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <pete...@gmx.net>
Date: Thu, 31 Aug 2017 12:24:47 -0400
Subject: [PATCH v2] Add background worker type
Add bgw_type field to background worker structure. It is intended to be
set to the same value for all workers of the same type, so they can be
grouped in pg_stat_activity, for example.
The backend_type column in pg_stat_activity now shows bgw_type for a
background worker. The ps listing and some log messages no longer call
out that a process is a "background worker" but just show the bgw_type.
That way, being a background worker is effectively an implementation
detail now that is not shown to the user.
---
contrib/pg_prewarm/autoprewarm.c | 6 ++--
doc/src/sgml/bgworker.sgml | 12 +++++--
src/backend/access/transam/parallel.c | 1 +
src/backend/postmaster/bgworker.c | 53 +++++++++++++++++++++++++++---
src/backend/postmaster/postmaster.c | 10 ++----
src/backend/replication/logical/launcher.c | 3 ++
src/backend/utils/adt/pgstatfuncs.c | 16 +++++++--
src/include/postmaster/bgworker.h | 2 ++
src/test/modules/test_shm_mq/setup.c | 2 +-
src/test/modules/worker_spi/worker_spi.c | 8 +++--
10 files changed, 91 insertions(+), 22 deletions(-)
diff --git a/contrib/pg_prewarm/autoprewarm.c b/contrib/pg_prewarm/autoprewarm.c
index cc0350e6d6..006c3153db 100644
--- a/contrib/pg_prewarm/autoprewarm.c
+++ b/contrib/pg_prewarm/autoprewarm.c
@@ -800,7 +800,8 @@ apw_start_master_worker(void)
worker.bgw_start_time = BgWorkerStart_ConsistentState;
strcpy(worker.bgw_library_name, "pg_prewarm");
strcpy(worker.bgw_function_name, "autoprewarm_main");
- strcpy(worker.bgw_name, "autoprewarm");
+ strcpy(worker.bgw_name, "autoprewarm master");
+ strcpy(worker.bgw_type, "autoprewarm master");
if (process_shared_preload_libraries_in_progress)
{
@@ -840,7 +841,8 @@ apw_start_database_worker(void)
worker.bgw_start_time = BgWorkerStart_ConsistentState;
strcpy(worker.bgw_library_name, "pg_prewarm");
strcpy(worker.bgw_function_name, "autoprewarm_database_main");
- strcpy(worker.bgw_name, "autoprewarm");
+ strcpy(worker.bgw_name, "autoprewarm worker");
+ strcpy(worker.bgw_type, "autoprewarm worker");
/* must set notify PID to wait for shutdown */
worker.bgw_notify_pid = MyProcPid;
diff --git a/doc/src/sgml/bgworker.sgml b/doc/src/sgml/bgworker.sgml
index b422323081..822632bf02 100644
--- a/doc/src/sgml/bgworker.sgml
+++ b/doc/src/sgml/bgworker.sgml
@@ -51,6 +51,7 @@ <title>Background Worker Processes</title>
typedef struct BackgroundWorker
{
char bgw_name[BGW_MAXLEN];
+ char bgw_type[BGW_MAXLEN];
int bgw_flags;
BgWorkerStartTime bgw_start_time;
int bgw_restart_time; /* in seconds, or BGW_NEVER_RESTART */
@@ -64,8 +65,15 @@ <title>Background Worker Processes</title>
</para>
<para>
- <structfield>bgw_name</> is a string to be used in log messages, process
- listings and similar contexts.
+ <structfield>bgw_name</> and <structfield>bgw_type</structfield> are
+ strings to be used in log messages, process listings and similar contexts.
+ <structfield>bgw_type</structfield> should be the same for all background
+ workers of the same type, so that it is possible to group such workers in a
+ process listing, for example. <structfield>bgw_name</structfield> on the
+ other hand can contain additional information about the specific process.
+ (Typically, the string for <structfield>bgw_name</structfield> will contain
+ the string for <structfield>bgw_type</structfield> somehow, but that is not
+ strictly required.)
</para>
<para>
diff --git a/src/backend/access/transam/parallel.c
b/src/backend/access/transam/parallel.c
index 17b10383e4..9828259e6d 100644
--- a/src/backend/access/transam/parallel.c
+++ b/src/backend/access/transam/parallel.c
@@ -438,6 +438,7 @@ LaunchParallelWorkers(ParallelContext *pcxt)
memset(&worker, 0, sizeof(worker));
snprintf(worker.bgw_name, BGW_MAXLEN, "parallel worker for PID %d",
MyProcPid);
+ snprintf(worker.bgw_type, BGW_MAXLEN, "parallel worker");
worker.bgw_flags =
BGWORKER_SHMEM_ACCESS | BGWORKER_BACKEND_DATABASE_CONNECTION
| BGWORKER_CLASS_PARALLEL;
diff --git a/src/backend/postmaster/bgworker.c
b/src/backend/postmaster/bgworker.c
index 28af6f0f07..da7d12d91a 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -344,6 +344,8 @@ BackgroundWorkerStateChange(void)
*/
ascii_safe_strlcpy(rw->rw_worker.bgw_name,
slot->worker.bgw_name,
BGW_MAXLEN);
+ ascii_safe_strlcpy(rw->rw_worker.bgw_type,
+ slot->worker.bgw_type,
BGW_MAXLEN);
ascii_safe_strlcpy(rw->rw_worker.bgw_library_name,
slot->worker.bgw_library_name, BGW_MAXLEN);
ascii_safe_strlcpy(rw->rw_worker.bgw_function_name,
@@ -630,6 +632,12 @@ SanityCheckBackgroundWorker(BackgroundWorker *worker, int
elevel)
return false;
}
+ /*
+ * If bgw_type is not filled in, use bgw_name.
+ */
+ if (strcmp(worker->bgw_type, "") == 0)
+ strcpy(worker->bgw_type, worker->bgw_name);
+
return true;
}
@@ -670,8 +678,8 @@ bgworker_die(SIGNAL_ARGS)
ereport(FATAL,
(errcode(ERRCODE_ADMIN_SHUTDOWN),
- errmsg("terminating background worker \"%s\" due to
administrator command",
- MyBgworkerEntry->bgw_name)));
+ errmsg("terminating %s due to administrator command",
+ MyBgworkerEntry->bgw_type)));
}
/*
@@ -700,7 +708,6 @@ void
StartBackgroundWorker(void)
{
sigjmp_buf local_sigjmp_buf;
- char buf[MAXPGPATH];
BackgroundWorker *worker = MyBgworkerEntry;
bgworker_main_type entrypt;
@@ -710,8 +717,7 @@ StartBackgroundWorker(void)
IsBackgroundWorker = true;
/* Identify myself via ps */
- snprintf(buf, MAXPGPATH, "bgworker: %s", worker->bgw_name);
- init_ps_display(buf, "", "", "");
+ init_ps_display(worker->bgw_name, "", "", "");
/*
* If we're not supposed to have shared memory access, then detach from
@@ -1233,3 +1239,40 @@ LookupBackgroundWorkerFunction(const char *libraryname,
const char *funcname)
return (bgworker_main_type)
load_external_function(libraryname, funcname, true, NULL);
}
+
+/*
+ * Given a PID, get the bgw_type of the background worker. Returns NULL if
+ * not a valid background worker.
+ *
+ * The return value is in static memory belonging to this function, so it has
+ * to be used before calling this function again. This is so that the caller
+ * doesn't have to worry about the background worker locking protocol.
+ */
+const char *
+GetBackgroundWorkerTypeByPid(pid_t pid)
+{
+ int slotno;
+ bool found = false;
+ static char result[BGW_MAXLEN];
+
+ LWLockAcquire(BackgroundWorkerLock, LW_SHARED);
+
+ for (slotno = 0; slotno < BackgroundWorkerData->total_slots; slotno++)
+ {
+ BackgroundWorkerSlot *slot =
&BackgroundWorkerData->slot[slotno];
+
+ if (slot->pid > 0 && slot->pid == pid)
+ {
+ strcpy(result, slot->worker.bgw_type);
+ found = true;
+ break;
+ }
+ }
+
+ LWLockRelease(BackgroundWorkerLock);
+
+ if (!found)
+ return NULL;
+
+ return result;
+}
diff --git a/src/backend/postmaster/postmaster.c
b/src/backend/postmaster/postmaster.c
index 95180b2ef5..cf4bffa8b3 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -3096,7 +3096,6 @@ static bool
CleanupBackgroundWorker(int pid,
int exitstatus) /* child's exit
status */
{
- char namebuf[MAXPGPATH];
slist_mutable_iter iter;
slist_foreach_modify(iter, &BackgroundWorkerList)
@@ -3114,9 +3113,6 @@ CleanupBackgroundWorker(int pid,
exitstatus = 0;
#endif
- snprintf(namebuf, MAXPGPATH, "%s: %s", _("worker process"),
- rw->rw_worker.bgw_name);
-
if (!EXIT_STATUS_0(exitstatus))
{
/* Record timestamp, so we know when to restart the
worker. */
@@ -3138,7 +3134,7 @@ CleanupBackgroundWorker(int pid,
{
if (!EXIT_STATUS_0(exitstatus) &&
!EXIT_STATUS_1(exitstatus))
{
- HandleChildCrash(pid, exitstatus, namebuf);
+ HandleChildCrash(pid, exitstatus,
rw->rw_worker.bgw_name);
return true;
}
}
@@ -3151,7 +3147,7 @@ CleanupBackgroundWorker(int pid,
if (!ReleasePostmasterChildSlot(rw->rw_child_slot) &&
(rw->rw_worker.bgw_flags & BGWORKER_SHMEM_ACCESS) != 0)
{
- HandleChildCrash(pid, exitstatus, namebuf);
+ HandleChildCrash(pid, exitstatus,
rw->rw_worker.bgw_name);
return true;
}
@@ -3176,7 +3172,7 @@ CleanupBackgroundWorker(int pid,
ReportBackgroundWorkerExit(&iter); /* report child death */
LogChildExit(EXIT_STATUS_0(exitstatus) ? DEBUG1 : LOG,
- namebuf, pid, exitstatus);
+ rw->rw_worker.bgw_name, pid,
exitstatus);
return true;
}
diff --git a/src/backend/replication/logical/launcher.c
b/src/backend/replication/logical/launcher.c
index 6c894421a3..cf5f02aef8 100644
--- a/src/backend/replication/logical/launcher.c
+++ b/src/backend/replication/logical/launcher.c
@@ -421,6 +421,7 @@ logicalrep_worker_launch(Oid dbid, Oid subid, const char
*subname, Oid userid,
else
snprintf(bgw.bgw_name, BGW_MAXLEN,
"logical replication worker for subscription
%u", subid);
+ snprintf(bgw.bgw_type, BGW_MAXLEN, "logical replication worker");
bgw.bgw_restart_time = BGW_NEVER_RESTART;
bgw.bgw_notify_pid = MyProcPid;
@@ -768,6 +769,8 @@ ApplyLauncherRegister(void)
snprintf(bgw.bgw_function_name, BGW_MAXLEN, "ApplyLauncherMain");
snprintf(bgw.bgw_name, BGW_MAXLEN,
"logical replication launcher");
+ snprintf(bgw.bgw_type, BGW_MAXLEN,
+ "logical replication launcher");
bgw.bgw_restart_time = 5;
bgw.bgw_notify_pid = 0;
bgw.bgw_main_arg = (Datum) 0;
diff --git a/src/backend/utils/adt/pgstatfuncs.c
b/src/backend/utils/adt/pgstatfuncs.c
index 20ce48b2d8..dd5898ec0a 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -21,6 +21,7 @@
#include "funcapi.h"
#include "miscadmin.h"
#include "pgstat.h"
+#include "postmaster/bgworker_internals.h"
#include "postmaster/postmaster.h"
#include "storage/proc.h"
#include "storage/procarray.h"
@@ -820,8 +821,19 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
}
}
/* Add backend type */
- values[17] =
-
CStringGetTextDatum(pgstat_get_backend_desc(beentry->st_backendType));
+ if (beentry->st_backendType == B_BG_WORKER)
+ {
+ const char *bgw_type;
+
+ bgw_type =
GetBackgroundWorkerTypeByPid(beentry->st_procpid);
+ if (bgw_type)
+ values[17] =
CStringGetTextDatum(bgw_type);
+ else
+ nulls[17] = true;
+ }
+ else
+ values[17] =
+
CStringGetTextDatum(pgstat_get_backend_desc(beentry->st_backendType));
}
else
{
diff --git a/src/include/postmaster/bgworker.h
b/src/include/postmaster/bgworker.h
index e2ecd3c9eb..6b4e631880 100644
--- a/src/include/postmaster/bgworker.h
+++ b/src/include/postmaster/bgworker.h
@@ -88,6 +88,7 @@ typedef enum
typedef struct BackgroundWorker
{
char bgw_name[BGW_MAXLEN];
+ char bgw_type[BGW_MAXLEN];
int bgw_flags;
BgWorkerStartTime bgw_start_time;
int bgw_restart_time; /* in seconds, or
BGW_NEVER_RESTART */
@@ -122,6 +123,7 @@ extern BgwHandleStatus
GetBackgroundWorkerPid(BackgroundWorkerHandle *handle,
extern BgwHandleStatus WaitForBackgroundWorkerStartup(BackgroundWorkerHandle
*handle, pid_t *pid);
extern BgwHandleStatus
WaitForBackgroundWorkerShutdown(BackgroundWorkerHandle
*);
+extern const char *GetBackgroundWorkerTypeByPid(pid_t pid);
/* Terminate a bgworker */
extern void TerminateBackgroundWorker(BackgroundWorkerHandle *handle);
diff --git a/src/test/modules/test_shm_mq/setup.c
b/src/test/modules/test_shm_mq/setup.c
index 3ae9018360..561f6f9bac 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -219,7 +219,7 @@ setup_background_workers(int nworkers, dsm_segment *seg)
worker.bgw_restart_time = BGW_NEVER_RESTART;
sprintf(worker.bgw_library_name, "test_shm_mq");
sprintf(worker.bgw_function_name, "test_shm_mq_main");
- snprintf(worker.bgw_name, BGW_MAXLEN, "test_shm_mq");
+ snprintf(worker.bgw_type, BGW_MAXLEN, "test_shm_mq");
worker.bgw_main_arg = UInt32GetDatum(dsm_segment_handle(seg));
/* set bgw_notify_pid, so we can detect if the worker stops */
worker.bgw_notify_pid = MyProcPid;
diff --git a/src/test/modules/worker_spi/worker_spi.c
b/src/test/modules/worker_spi/worker_spi.c
index 12c8cd5774..4c6ab6d575 100644
--- a/src/test/modules/worker_spi/worker_spi.c
+++ b/src/test/modules/worker_spi/worker_spi.c
@@ -111,7 +111,7 @@ initialize_worker_spi(worktable *table)
StartTransactionCommand();
SPI_connect();
PushActiveSnapshot(GetTransactionSnapshot());
- pgstat_report_activity(STATE_RUNNING, "initializing spi_worker schema");
+ pgstat_report_activity(STATE_RUNNING, "initializing worker_spi schema");
/* XXX could we use CREATE SCHEMA IF NOT EXISTS? */
initStringInfo(&buf);
@@ -359,7 +359,8 @@ _PG_init(void)
*/
for (i = 1; i <= worker_spi_total_workers; i++)
{
- snprintf(worker.bgw_name, BGW_MAXLEN, "worker %d", i);
+ snprintf(worker.bgw_name, BGW_MAXLEN, "worker_spi worker %d",
i);
+ snprintf(worker.bgw_type, BGW_MAXLEN, "worker_spi");
worker.bgw_main_arg = Int32GetDatum(i);
RegisterBackgroundWorker(&worker);
@@ -385,7 +386,8 @@ worker_spi_launch(PG_FUNCTION_ARGS)
worker.bgw_restart_time = BGW_NEVER_RESTART;
sprintf(worker.bgw_library_name, "worker_spi");
sprintf(worker.bgw_function_name, "worker_spi_main");
- snprintf(worker.bgw_name, BGW_MAXLEN, "worker %d", i);
+ snprintf(worker.bgw_name, BGW_MAXLEN, "worker_spi worker %d", i);
+ snprintf(worker.bgw_type, BGW_MAXLEN, "worker_spi");
worker.bgw_main_arg = Int32GetDatum(i);
/* set bgw_notify_pid so that we can use WaitForBackgroundWorkerStartup
*/
worker.bgw_notify_pid = MyProcPid;
base-commit: b5c75feca7ffb2667c42b86286e262d6cb709b76
--
2.14.1
--
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