From 1d8179696b641284e69c5c4cc32d0a436856737e Mon Sep 17 00:00:00 2001 From: Tomas Vondra Date: Mon, 29 Sep 2025 21:21:37 +0200 Subject: [PATCH v20250930 08/22] BufFileCreateCompressTemp - cleanup and comments --- src/backend/storage/file/buffile.c | 32 ++++++++++++++++++++---------- 1 file changed, 21 insertions(+), 11 deletions(-) diff --git a/src/backend/storage/file/buffile.c b/src/backend/storage/file/buffile.c index 6a43ad1ee38..7cfca79ab5c 100644 --- a/src/backend/storage/file/buffile.c +++ b/src/backend/storage/file/buffile.c @@ -261,14 +261,12 @@ BufFileCreateCompressTemp(bool interXact) static char *buff = NULL; static int allocated_for_compression = TEMP_NONE_COMPRESSION; static int allocated_size = 0; - BufFile *tmpBufFile = BufFileCreateTemp(interXact); + BufFile *file = BufFileCreateTemp(interXact); if (temp_file_compression != TEMP_NONE_COMPRESSION) { int size = 0; - tmpBufFile->compress = true; - switch (temp_file_compression) { case TEMP_LZ4_COMPRESSION: @@ -282,28 +280,40 @@ BufFileCreateCompressTemp(bool interXact) } /* - * Allocate or reallocate buffer if needed: - Buffer is NULL (first - * time) - Compression type changed - Current buffer is too small + * Allocate or reallocate buffer if needed - first call, compression + * method changed, or the buffer is too small. + * + * XXX Can the buffer be too small if the method did not change? Does the + * method matter, or just the size? */ - if (buff == NULL || - allocated_for_compression != temp_file_compression || - allocated_size < size) + if ((buff == NULL) || + (allocated_for_compression != temp_file_compression) || + (allocated_size < size)) { + /* + * FIXME Isn't this pfree wrong? How do we know the buffer is not + * used by some existing temp file? + */ if (buff != NULL) pfree(buff); /* - * Persistent buffer for all temporary file compressions + * Persistent buffer for all temporary file compressions. */ buff = MemoryContextAlloc(TopMemoryContext, size); allocated_for_compression = temp_file_compression; allocated_size = size; } - tmpBufFile->cBuffer = buff; + file->compress = true; + file->cBuffer = buff; } - return tmpBufFile; + /* compression with buffer, or no compression and no buffer */ + Assert((!file->compress && file->cBuffer == NULL) || + (file->compress && file->cBuffer != NULL)); + + return file; } /* -- 2.51.0