From a32f95d3b129d386ce03c194bd6cddad2f92b76b Mon Sep 17 00:00:00 2001 From: Nathan Bossart Date: Thu, 7 Apr 2022 14:11:59 -0700 Subject: [PATCH v4 1/2] Reduce overhead of renaming archive status files. Presently, archive status files are durably renamed from .ready to .done to indicate that a file has been archived. Persisting this rename to disk accounts for a significant amount of the overhead associated with archiving. While durably renaming the file prevents re-archiving in most cases, archive commands and libraries must already gracefully handle attempts to re-archive the last archived file after a crash (e.g., a crash immediately after archive_command exits but before the server renames the status file). This change reduces the amount of overhead associated with archiving by using rename() instead of durable_rename() to rename the archive status files. As a consequence, the server is more likely to attempt to re-archive files after a crash, but as noted above, archive commands and modules are already expected to handle this. It is also possible that the server will attempt to re- archive files that have been removed or recycled, but the archiver already handles this, too. Author: Nathan Bossart --- src/backend/postmaster/pgarch.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c index 25e31c42e1..6ce361707d 100644 --- a/src/backend/postmaster/pgarch.c +++ b/src/backend/postmaster/pgarch.c @@ -745,7 +745,19 @@ pgarch_archiveDone(char *xlog) StatusFilePath(rlogready, xlog, ".ready"); StatusFilePath(rlogdone, xlog, ".done"); - (void) durable_rename(rlogready, rlogdone, WARNING); + + /* + * To avoid extra overhead, we don't durably rename the .ready file to + * .done. Archive commands and libraries must gracefully handle attempts + * to re-archive files (e.g., if the server crashes just before this + * function is called), so it should be okay if the .ready file reappears + * after a crash. + */ + if (rename(rlogready, rlogdone) < 0) + ereport(WARNING, + (errcode_for_file_access(), + errmsg("could not rename file \"%s\" to \"%s\": %m", + rlogready, rlogdone))); } -- 2.25.1