From e9d1e4dcbf17200f34cdb857c7961fb0df1e8435 Mon Sep 17 00:00:00 2001 From: Tomas Vondra Date: Mon, 13 Mar 2023 20:42:21 +0100 Subject: [PATCH 3/4] questions --- src/bin/pg_dump/compress_io.h | 1 + src/bin/pg_dump/compress_lz4.c | 6 ++++++ 2 files changed, 7 insertions(+) diff --git a/src/bin/pg_dump/compress_io.h b/src/bin/pg_dump/compress_io.h index cdb15951ea..ae32a4de1c 100644 --- a/src/bin/pg_dump/compress_io.h +++ b/src/bin/pg_dump/compress_io.h @@ -18,6 +18,7 @@ #include "pg_backup_archiver.h" /* Initial buffer sizes used in zlib compression. */ +/* XXX shouldn't this be moved to compress_gzip.c? */ #define ZLIB_OUT_SIZE 4096 #define ZLIB_IN_SIZE 4096 diff --git a/src/bin/pg_dump/compress_lz4.c b/src/bin/pg_dump/compress_lz4.c index 9ab57ceff3..94f28d6806 100644 --- a/src/bin/pg_dump/compress_lz4.c +++ b/src/bin/pg_dump/compress_lz4.c @@ -20,6 +20,8 @@ #include #include +/* Initial buffer sizes used in zlib compression. */ +/* XXX Why is this different from GZIP values? That uses 4kB for both. */ #define LZ4_OUT_SIZE (4 * 1024) #define LZ4_IN_SIZE (16 * 1024) @@ -207,6 +209,10 @@ LZ4File_init(LZ4File *fs, int size, bool compressing) if (fs->compressing) { fs->buflen = LZ4F_compressBound(LZ4_IN_SIZE, &fs->prefs); + /* + * XXX Does this actually do something meaningful? With LZ4_IN_SIZE=16kB + * I get buflen=143600 (roughly), so can it ever be smaller than 22? + */ if (fs->buflen < LZ4F_HEADER_SIZE_MAX) fs->buflen = LZ4F_HEADER_SIZE_MAX; -- 2.39.2