From 3efb91201fce65c51030db1871a816bf42af198d Mon Sep 17 00:00:00 2001 From: Seongjun Shin Date: Fri, 29 May 2026 14:52:11 +0900 Subject: [PATCH v9 2/2] Add wait events for Windows-specific logging output paths On Windows, log output goes through paths other than write(2) that can also block: write_console() emits to the console with WriteConsoleW(), and write_eventlog() writes to the Windows event log with ReportEventW()/ReportEventA(). Like the write(2) path, these calls can block and previously left wait_event IS NULL in pg_stat_activity. Wrap WriteConsoleW() with the StderrWrite event introduced in the previous patch, and add a new EventlogWrite event for the event log path: IO / EventlogWrite - ReportEventW()/ReportEventA() inside write_eventlog(). This instruments the Windows logging paths consistently with the write(2) and syslog(3) paths, using the same nested start/end helpers so that a wait event published by the caller survives the write. It is split out from the previous patch since it is platform-specific. EventlogWrite was confirmed at runtime on Windows through a CI job rigged to fail if the event is never sampled. WriteConsoleW cannot be exercised without a real console, so it is covered by build and review only. Author: Seongjun Shin Reviewed-by: Kirk Wolak Reviewed-by: Kyotaro Horiguchi Reviewed-by: Michael Paquier Reviewed-by: Henson Choi Reviewed-by: Nikolay Samokhvalov Tested-by: Nikolay Samokhvalov Discussion: https://postgr.es/m/CACdN0M78U+GvpqA7oey-GA7fFSYM636aDp6H9FVvCztv9zXxSA@mail.gmail.com --- src/backend/utils/activity/wait_event_names.txt | 1 + src/backend/utils/error/elog.c | 16 +++++++++++++++- 2 files changed, 16 insertions(+), 1 deletion(-) diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt index 4c64bceb47b..adb9a6cbc55 100644 --- a/src/backend/utils/activity/wait_event_names.txt +++ b/src/backend/utils/activity/wait_event_names.txt @@ -229,6 +229,7 @@ DATA_FILE_TRUNCATE "Waiting for a relation data file to be truncated." DATA_FILE_WRITE "Waiting for a write to a relation data file." DSM_ALLOCATE "Waiting for a dynamic shared memory segment to be allocated." DSM_FILL_ZERO_WRITE "Waiting to fill a dynamic shared memory backing file with zeroes." +EVENTLOG_WRITE "Waiting for a write to the Windows event log." LOCK_FILE_ADDTODATADIR_READ "Waiting for a read while adding a line to the data directory lock file." LOCK_FILE_ADDTODATADIR_SYNC "Waiting for data to reach durable storage while adding a line to the data directory lock file." LOCK_FILE_ADDTODATADIR_WRITE "Waiting for a write while adding a line to the data directory lock file." diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c index 0fb489ed563..a9bda78f0ed 100644 --- a/src/backend/utils/error/elog.c +++ b/src/backend/utils/error/elog.c @@ -2956,6 +2956,7 @@ write_eventlog(int level, const char *line, int len) { int eventlevel = EVENTLOG_ERROR_TYPE; static HANDLE evtHandle = INVALID_HANDLE_VALUE; + uint32 outer_wait_event_info; if (evtHandle == INVALID_HANDLE_VALUE) { @@ -3018,6 +3019,9 @@ write_eventlog(int level, const char *line, int len) { const WCHAR *utf16_const = utf16; + /* See write_console() for why the nested variants are used. */ + outer_wait_event_info = + pgstat_report_wait_start_nested(WAIT_EVENT_EVENTLOG_WRITE); ReportEventW(evtHandle, eventlevel, 0, @@ -3027,12 +3031,15 @@ write_eventlog(int level, const char *line, int len) 0, &utf16_const, NULL); + pgstat_report_wait_end_nested(outer_wait_event_info); /* XXX Try ReportEventA() when ReportEventW() fails? */ pfree(utf16); return; } } + outer_wait_event_info = + pgstat_report_wait_start_nested(WAIT_EVENT_EVENTLOG_WRITE); ReportEventA(evtHandle, eventlevel, 0, @@ -3042,6 +3049,7 @@ write_eventlog(int level, const char *line, int len) 0, &line, NULL); + pgstat_report_wait_end_nested(outer_wait_event_info); } #endif /* WIN32 */ @@ -3082,9 +3090,15 @@ write_console(const char *line, int len) { HANDLE stdHandle; DWORD written; + BOOL ok; stdHandle = GetStdHandle(STD_ERROR_HANDLE); - if (WriteConsoleW(stdHandle, utf16, utf16len, &written, NULL)) + /* see the comment at the write() below */ + outer_wait_event_info = + pgstat_report_wait_start_nested(WAIT_EVENT_STDERR_WRITE); + ok = WriteConsoleW(stdHandle, utf16, utf16len, &written, NULL); + pgstat_report_wait_end_nested(outer_wait_event_info); + if (ok) { pfree(utf16); return; -- 2.50.1 (Apple Git-155)