From 591e58e31881d86dc0acc3bd9ca67aeed80a1041 Mon Sep 17 00:00:00 2001 From: Bharath Rupireddy Date: Thu, 20 Oct 2022 07:12:17 +0000 Subject: [PATCH v3] Remove leftover temporary files via basic_archive shutdown callback --- contrib/basic_archive/basic_archive.c | 32 +++++++++++++++++++++++---- doc/src/sgml/basic-archive.sgml | 5 ++++- 2 files changed, 32 insertions(+), 5 deletions(-) diff --git a/contrib/basic_archive/basic_archive.c b/contrib/basic_archive/basic_archive.c index 9f221816bb..f971b166be 100644 --- a/contrib/basic_archive/basic_archive.c +++ b/contrib/basic_archive/basic_archive.c @@ -42,10 +42,12 @@ PG_MODULE_MAGIC; static char *archive_directory = NULL; static MemoryContext basic_archive_context; +static char tempfilepath[MAXPGPATH + 256]; static bool basic_archive_configured(void); static bool basic_archive_file(const char *file, const char *path); static void basic_archive_file_internal(const char *file, const char *path); +static void basic_archive_shutdown(void); static bool check_archive_directory(char **newval, void **extra, GucSource source); static bool compare_files(const char *file1, const char *file2); @@ -85,6 +87,7 @@ _PG_archive_module_init(ArchiveModuleCallbacks *cb) cb->check_configured_cb = basic_archive_configured; cb->archive_file_cb = basic_archive_file; + cb->shutdown_cb = basic_archive_shutdown; } /* @@ -215,11 +218,12 @@ static void basic_archive_file_internal(const char *file, const char *path) { char destination[MAXPGPATH]; - char temp[MAXPGPATH + 256]; struct stat st; struct timeval tv; uint64 epoch; /* milliseconds */ + MemSet(tempfilepath, '\0', sizeof(tempfilepath)); + ereport(DEBUG3, (errmsg("archiving \"%s\" via basic_archive", file))); @@ -268,21 +272,28 @@ basic_archive_file_internal(const char *file, const char *path) pg_add_u64_overflow(epoch, (uint64) (tv.tv_usec / 1000), &epoch)) elog(ERROR, "could not generate temporary file name for archiving"); - snprintf(temp, sizeof(temp), "%s/%s.%s.%d." UINT64_FORMAT, + snprintf(tempfilepath, sizeof(tempfilepath), "%s/%s.%s.%d." UINT64_FORMAT, archive_directory, "archtemp", file, MyProcPid, epoch); /* * Copy the file to its temporary destination. Note that this will fail * if temp already exists. */ - copy_file(unconstify(char *, path), temp); + copy_file(unconstify(char *, path), tempfilepath); /* * Sync the temporary file to disk and move it to its final destination. * Note that this will overwrite any existing file, but this is only * possible if someone else created the file since the stat() above. */ - (void) durable_rename(temp, destination, ERROR); + (void) durable_rename(tempfilepath, destination, ERROR); + + /* + * Reset tempfilepath after renaming the temporary file to the final file + * so that the shutdown callback, if called after this point, will not + * attempt to remove it and fail. + */ + MemSet(tempfilepath, '\0', sizeof(tempfilepath)); ereport(DEBUG1, (errmsg("archived \"%s\" via basic_archive", file))); @@ -368,3 +379,16 @@ compare_files(const char *file1, const char *file2) return ret; } + +static void +basic_archive_shutdown(void) +{ + if (tempfilepath[0] == '\0') + return; + + /* Remove the leftover temporary file. */ + if (unlink(tempfilepath) < 0) + ereport(WARNING, + (errcode_for_file_access(), + errmsg("could not unlink file \"%s\": %m", tempfilepath))); +} diff --git a/doc/src/sgml/basic-archive.sgml b/doc/src/sgml/basic-archive.sgml index 0b650f17a8..d14bc083af 100644 --- a/doc/src/sgml/basic-archive.sgml +++ b/doc/src/sgml/basic-archive.sgml @@ -38,7 +38,10 @@ directory must already exist. The default is an empty string, which effectively halts WAL archiving, but if is enabled, the server will accumulate WAL segment files in the - expectation that a value will soon be provided. + expectation that a value will soon be provided. Care must be taken when + multiple servers are archiving to the same + basic_archive.archive_library directory as they all + might try to archive the same WAL file. -- 2.34.1