From f0a545ccfbde0b7d5cf23968c8a6d3d919bb1455 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Jan=20Lindstr=C3=B6m?= Date: Wed, 29 Oct 2014 10:42:27 +0200 Subject: [PATCH] MDEV-6935: Change the default value for innodb_log_compressed_pages to false Merge Facebook commit ca40b4417fd224a68de6636b58c92f133703fc68 authored by Steaphan Greene from https://github.com/facebook/mysql-5.6 Change the default value for innodb_log_compressed_pages to false Logging these pages is a waste. We don't want this to be enabled. One caution here: If the zlib version used by innodb is changed, but the running version is still the previous version, and the running version crashes, it is possible crash recovery could fail. When crash recovery uses a zlib version at all different than the version used by the crashed instance, it is possible that a redone compression could fail, where the original did not, because the new zlib version compresses the same data to a slightly larger size. Because of the nature of compression, this is even possible when upgrading to a version of zlib which actually peforms overall better compression than the previous version. If this happens, mysql will fail to recover, since a page split can not be safely triggered during crash recovery. So, either the exact zlib version must be controlled between builds, or these rare recovery failures must be accepted. The cost of logging these pages is quite high, so we consider this limitation to be worthwhile. This failure scenario can not happen if there was a clean shutdown. This is only relevant to restarting crashed instances, or starting an instance built via a hot backup too (XtraBackup). --- .../suite/sys_vars/r/innodb_log_compressed_pages_basic.result | 4 ++-- mysql-test/suite/sys_vars/r/sysvars_innodb.result | 4 ++-- storage/innobase/handler/ha_innodb.cc | 2 +- storage/innobase/page/page0zip.cc | 2 +- storage/xtradb/handler/ha_innodb.cc | 2 +- storage/xtradb/page/page0zip.cc | 2 +- 6 files changed, 8 insertions(+), 8 deletions(-) diff --git a/mysql-test/suite/sys_vars/r/innodb_log_compressed_pages_basic.result b/mysql-test/suite/sys_vars/r/innodb_log_compressed_pages_basic.result index 8cb8d900b595e..3b1ad38fd31dd 100644 --- a/mysql-test/suite/sys_vars/r/innodb_log_compressed_pages_basic.result +++ b/mysql-test/suite/sys_vars/r/innodb_log_compressed_pages_basic.result @@ -1,7 +1,7 @@ SET @start_global_value = @@global.innodb_log_compressed_pages; SELECT @start_global_value; @start_global_value -1 +0 '#---------------------BS_STVARS_028_01----------------------#' SELECT COUNT(@@GLOBAL.innodb_log_compressed_pages); COUNT(@@GLOBAL.innodb_log_compressed_pages) @@ -66,4 +66,4 @@ ERROR 42S22: Unknown column 'innodb_log_compressed_pages' in 'field list' SET @@global.innodb_log_compressed_pages = @start_global_value; SELECT @@global.innodb_log_compressed_pages; @@global.innodb_log_compressed_pages -1 +0 diff --git a/mysql-test/suite/sys_vars/r/sysvars_innodb.result b/mysql-test/suite/sys_vars/r/sysvars_innodb.result index ea35f2f556f80..f3bc9eead9c48 100644 --- a/mysql-test/suite/sys_vars/r/sysvars_innodb.result +++ b/mysql-test/suite/sys_vars/r/sysvars_innodb.result @@ -1141,9 +1141,9 @@ READ_ONLY NO COMMAND_LINE_ARGUMENT OPTIONAL VARIABLE_NAME INNODB_LOG_COMPRESSED_PAGES SESSION_VALUE NULL -GLOBAL_VALUE ON +GLOBAL_VALUE OFF GLOBAL_VALUE_ORIGIN COMPILE-TIME -DEFAULT_VALUE ON +DEFAULT_VALUE OFF VARIABLE_SCOPE GLOBAL VARIABLE_TYPE BOOLEAN VARIABLE_COMMENT Enables/disables the logging of entire compressed page images. InnoDB logs the compressed pages to prevent corruption if the zlib compression algorithm changes. When turned OFF, InnoDB will assume that the zlib compression algorithm doesn't change. diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc index df448e85da996..ee06401be2452 100644 --- a/storage/innobase/handler/ha_innodb.cc +++ b/storage/innobase/handler/ha_innodb.cc @@ -18151,7 +18151,7 @@ static MYSQL_SYSVAR_BOOL(log_compressed_pages, page_zip_log_pages, " the zlib compression algorithm changes." " When turned OFF, InnoDB will assume that the zlib" " compression algorithm doesn't change.", - NULL, NULL, TRUE); + NULL, NULL, FALSE); static MYSQL_SYSVAR_LONG(additional_mem_pool_size, innobase_additional_mem_pool_size, PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY, diff --git a/storage/innobase/page/page0zip.cc b/storage/innobase/page/page0zip.cc index 71660dfc1ae88..b0cb9407e72b6 100644 --- a/storage/innobase/page/page0zip.cc +++ b/storage/innobase/page/page0zip.cc @@ -76,7 +76,7 @@ UNIV_INTERN uint page_zip_level = DEFAULT_COMPRESSION_LEVEL; /* Whether or not to log compressed page images to avoid possible compression algorithm changes in zlib. */ -UNIV_INTERN my_bool page_zip_log_pages = true; +UNIV_INTERN my_bool page_zip_log_pages = false; /* Please refer to ../include/page0zip.ic for a description of the compressed page format. */ diff --git a/storage/xtradb/handler/ha_innodb.cc b/storage/xtradb/handler/ha_innodb.cc index e5090a86f602e..43349146c1411 100644 --- a/storage/xtradb/handler/ha_innodb.cc +++ b/storage/xtradb/handler/ha_innodb.cc @@ -19254,7 +19254,7 @@ static MYSQL_SYSVAR_BOOL(log_compressed_pages, page_zip_log_pages, " the zlib compression algorithm changes." " When turned OFF, InnoDB will assume that the zlib" " compression algorithm doesn't change.", - NULL, NULL, TRUE); + NULL, NULL, FALSE); static MYSQL_SYSVAR_LONG(additional_mem_pool_size, innobase_additional_mem_pool_size, PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY, diff --git a/storage/xtradb/page/page0zip.cc b/storage/xtradb/page/page0zip.cc index a12d30a806339..1991d01ce4877 100644 --- a/storage/xtradb/page/page0zip.cc +++ b/storage/xtradb/page/page0zip.cc @@ -77,7 +77,7 @@ UNIV_INTERN uint page_zip_level = DEFAULT_COMPRESSION_LEVEL; /* Whether or not to log compressed page images to avoid possible compression algorithm changes in zlib. */ -UNIV_INTERN my_bool page_zip_log_pages = true; +UNIV_INTERN my_bool page_zip_log_pages = false; /* Please refer to ../include/page0zip.ic for a description of the compressed page format. */