From 785b8d6ab312e5bee0846094fe06982c1d4c07f2 Mon Sep 17 00:00:00 2001 From: Magnus Hagander Date: Sun, 27 May 2012 10:54:31 +0200 Subject: [PATCH] Fix handling of pg_stat_statements.stat temporary file Write the file to a temporary name and then rename() it into the permanent name, to ensure it can't end up half-written and corrupt in case of a crash during shutdown. Unlink the file after it has been read so it's removed from the data directory and not included in base backups going to replication slaves. --- .../pg_stat_statements/pg_stat_statements.c | 22 ++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) diff --git a/contrib/pg_stat_statements/pg_stat_statements.c b/contrib/pg_stat_statements/pg_stat_statements.c index eb89aeca80..66a949c604 100644 --- a/contrib/pg_stat_statements/pg_stat_statements.c +++ b/contrib/pg_stat_statements/pg_stat_statements.c @@ -418,6 +418,13 @@ pgss_shmem_startup(void) pfree(buffer); FreeFile(file); + + /* + * Remove the file so it's not included in backups/replication + * slaves, etc. A new file will be written on next shutdown. + */ + unlink(PGSS_DUMP_FILE); + return; error: @@ -459,7 +466,7 @@ pgss_shmem_shutdown(int code, Datum arg) if (!pgss_save) return; - file = AllocateFile(PGSS_DUMP_FILE, PG_BINARY_W); + file = AllocateFile(PGSS_DUMP_FILE ".tmp", PG_BINARY_W); if (file == NULL) goto error; @@ -485,16 +492,25 @@ pgss_shmem_shutdown(int code, Datum arg) goto error; } + /* + * Rename file into place, so we atomically replace the old one. + */ + if (rename(PGSS_DUMP_FILE ".tmp", PGSS_DUMP_FILE) != 0) + ereport(LOG, + (errcode_for_file_access(), + errmsg("could not rename pg_stat_statement file \"%s\": %m", + PGSS_DUMP_FILE ".tmp"))); + return; error: ereport(LOG, (errcode_for_file_access(), errmsg("could not write pg_stat_statement file \"%s\": %m", - PGSS_DUMP_FILE))); + PGSS_DUMP_FILE ".tmp"))); if (file) FreeFile(file); - unlink(PGSS_DUMP_FILE); + unlink(PGSS_DUMP_FILE ".tmp"); } /* -- 2.40.0