postgres.git / summary / log / commit / refs

commit    7bae3bbf62d63cdd49ae4ca4a851cef0cdbe6ab5
Author:   Thomas Munro <tmunro@postgresql.org>
Date:     Thu Jul 14 10:52:13 2022 +0000
First released in: 16.0

    Create a distinct wait event for POSIX DSM allocation.
    
    Previously we displayed "DSMFillZeroWrite" while in posix_fallocate(),
    because we shared the same wait event for "mmap" and "posix" DSM types.
    Let's introduce a new wait event "DSMAllocate", to be more accurate.
    
    Reported-by: Andres Freund <andres@anarazel.de>
    Discussion: https://postgr.es/m/20220711174518.yldckniicknsxgzl%40awork3.anarazel.de


 doc/src/sgml/monitoring.sgml            | 5 +++++
 src/backend/storage/ipc/dsm_impl.c      | 2 +-
 src/backend/utils/activity/wait_event.c | 3 +++
 src/include/utils/wait_event.h          | 1 +
 4 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 4549c2560e3..f2066e5f0f5 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -1296,6 +1296,11 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
       <entry><literal>CopyFileWrite</literal></entry>
       <entry>Waiting for a write during a file copy operation.</entry>
      </row>
+     <row>
+      <entry><literal>DSMAllocate</literal></entry>
+      <entry>Waiting for a dynamic shared memory segment to be
+       allocated.</entry>
+     </row>
      <row>
       <entry><literal>DSMFillZeroWrite</literal></entry>
       <entry>Waiting to fill a dynamic shared memory backing file with
diff --git a/src/backend/storage/ipc/dsm_impl.c b/src/backend/storage/ipc/dsm_impl.c
index 6f21a757758..258d47bcfac 100644
--- a/src/backend/storage/ipc/dsm_impl.c
+++ b/src/backend/storage/ipc/dsm_impl.c
@@ -364,7 +364,7 @@ dsm_impl_posix_resize(int fd, off_t size)
 	 */
 	PG_SETMASK(&BlockSig);
 
-	pgstat_report_wait_start(WAIT_EVENT_DSM_FILL_ZERO_WRITE);
+	pgstat_report_wait_start(WAIT_EVENT_DSM_ALLOCATE);
 #if defined(HAVE_POSIX_FALLOCATE) && defined(__linux__)
 	/*
 	 * On Linux, a shm_open fd is backed by a tmpfs file.  If we were to use
diff --git a/src/backend/utils/activity/wait_event.c b/src/backend/utils/activity/wait_event.c
index 87c15b9c6f3..da57a93034e 100644
--- a/src/backend/utils/activity/wait_event.c
+++ b/src/backend/utils/activity/wait_event.c
@@ -585,6 +585,9 @@ pgstat_get_wait_io(WaitEventIO w)
 		case WAIT_EVENT_DATA_FILE_WRITE:
 			event_name = "DataFileWrite";
 			break;
+		case WAIT_EVENT_DSM_ALLOCATE:
+			event_name = "DSMAllocate";
+			break;
 		case WAIT_EVENT_DSM_FILL_ZERO_WRITE:
 			event_name = "DSMFillZeroWrite";
 			break;
diff --git a/src/include/utils/wait_event.h b/src/include/utils/wait_event.h
index b578e2ec757..c3ade011206 100644
--- a/src/include/utils/wait_event.h
+++ b/src/include/utils/wait_event.h
@@ -178,6 +178,7 @@ typedef enum
 	WAIT_EVENT_DATA_FILE_SYNC,
 	WAIT_EVENT_DATA_FILE_TRUNCATE,
 	WAIT_EVENT_DATA_FILE_WRITE,
+	WAIT_EVENT_DSM_ALLOCATE,
 	WAIT_EVENT_DSM_FILL_ZERO_WRITE,
 	WAIT_EVENT_LOCK_FILE_ADDTODATADIR_READ,
 	WAIT_EVENT_LOCK_FILE_ADDTODATADIR_SYNC,


[parent: 712704d3539e]