Remove useless LZ4 system call on failure when writing file header

michaelpq · michaelpq · commit f79962d8264b · 2021-11-24T20:12:54.000+09:00
If an error occurs when writing the LZ4 file header, LZ4F_compressEnd() was called in the error code path of write(), followed by LZ4F_freeCompressionContext() to finish the cleanup. The code as-is was not broken, but the LZ4F_compressEnd() proves to not be necessary as there are no contents to flush at this stage, so remove it. Per gripe from Jeevan Ladhe and Robert Haas. Discussion: https://postgr.es/m/CAOgcT0PE33wbD7giAT1OSkNJt=p-vu8huq++qh=ny9O=SCP5aA@mail.gmail.com
diff --git a/src/bin/pg_basebackup/walmethods.c b/src/bin/pg_basebackup/walmethods.c
@@ -193,7 +193,6 @@ dir_open_for_write(const char *pathname, const char *temp_suffix, size_t pad_to_
 		{
 			/* If write didn't set errno, assume problem is no disk space */
 			dir_data->lasterrno = errno ? errno : ENOSPC;
-			(void) LZ4F_compressEnd(ctx, lz4buf, lz4bufsize, NULL);
 			(void) LZ4F_freeCompressionContext(ctx);
 			pg_free(lz4buf);
 			close(fd);

Original file line number	Diff line number	Diff line change
`@@ -193,7 +193,6 @@ dir_open_for_write(const char pathname, const char temp_suffix, size_t pad_to_`
`193`	`193`	`{`
`194`	`194`	`/* If write didn't set errno, assume problem is no disk space */`
`195`	`195`	`dir_data->lasterrno = errno ? errno : ENOSPC;`
`196`		`- (void) LZ4F_compressEnd(ctx, lz4buf, lz4bufsize, NULL);`
`197`	`196`	`(void) LZ4F_freeCompressionContext(ctx);`
`198`	`197`	`pg_free(lz4buf);`
`199`	`198`	`close(fd);`