MDEV-13247 innodb_log_compressed_pages=OFF breaks crash recovery of ROW_FORMAT=COMPRESSED tables

The option innodb_log_compressed_pages was contributed by
Facebook to MySQL 5.6. It was disabled in the 5.6.10 GA release
due to problems that were fixed in 5.6.11, which is when the
option was enabled.

The option was set to innodb_log_compressed_pages=ON by default
(disabling the feature), because safety was considered more
important than speed. The option innodb_log_compressed_pages=OFF
can *CORRUPT* ROW_FORMAT=COMPRESSED tables on crash recovery
if the zlib deflate function is behaving differently (producing
a different amount of compressed data) from how it behaved
when the redo log records were written (prior to the crash recovery).

In MDEV-6935, the default value was changed to
innodb_log_compressed_pages=OFF. This is inherently unsafe, because
there are very many different environments where MariaDB can be
running, using different zlib versions. While zlib can decompress
data just fine, there are no guarantees that different versions will
always compress the same data to the exactly same size. To avoid
problems related to zlib upgrades or version mismatch, we must
use a safe default setting.

This will reduce the write performance for users of
ROW_FORMAT=COMPRESSED tables. If you configure
innodb_log_compressed_pages=ON, please make sure that you will
always cleanly shut down InnoDB before upgrading the server
or zlib.

mysql-test/suite/sys_vars/r/innodb_log_compressed_pages_basic.result

 SET @start_global_value = @@global.innodb_log_compressed_pages;
 SELECT @start_global_value;
 @start_global_value
-0
+1
 '#---------------------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
-0
+1

mysql-test/suite/sys_vars/r/sysvars_innodb,32bit,xtradb.rdiff

@@ -705,7 +705,7 @@
 +COMMAND_LINE_ARGUMENT	REQUIRED
 +VARIABLE_NAME	INNODB_LOG_COMPRESSED_PAGES
  SESSION_VALUE	NULL
- GLOBAL_VALUE	OFF
+ GLOBAL_VALUE	ON
  GLOBAL_VALUE_ORIGIN	COMPILE-TIME
 @@ -1397,7 +1677,7 @@
  GLOBAL_VALUE_ORIGIN	CONFIG

mysql-test/suite/sys_vars/r/sysvars_innodb,xtradb.rdiff

@@ -379,7 +379,7 @@
 +COMMAND_LINE_ARGUMENT	REQUIRED
  VARIABLE_NAME	INNODB_LOG_COMPRESSED_PAGES
  SESSION_VALUE	NULL
- GLOBAL_VALUE	OFF
+ GLOBAL_VALUE	ON
 @@ -1447,6 +1727,34 @@
  ENUM_VALUE_LIST	NULL
  READ_ONLY	NO

mysql-test/suite/sys_vars/r/sysvars_innodb.result

@@ -1393,9 +1393,9 @@ READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	OPTIONAL
 VARIABLE_NAME	INNODB_LOG_COMPRESSED_PAGES
 SESSION_VALUE	NULL
-GLOBAL_VALUE	OFF
+GLOBAL_VALUE	ON
 GLOBAL_VALUE_ORIGIN	COMPILE-TIME
-DEFAULT_VALUE	OFF
+DEFAULT_VALUE	ON
 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.

storage/innobase/handler/ha_innodb.cc

@@ -19147,7 +19147,7 @@ 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, FALSE);
+  NULL, NULL, TRUE);
 
 static MYSQL_SYSVAR_LONG(additional_mem_pool_size, innobase_additional_mem_pool_size,
   PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,

storage/innobase/page/page0zip.cc

@@ -2,7 +2,7 @@
 
 Copyright (c) 2005, 2016, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2012, Facebook Inc.
-Copyright (c) 2017, MariaDB Corporation.
+Copyright (c) 2014, 2017, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -82,12 +82,12 @@ UNIV_INTERN mysql_pfs_key_t		page_zip_stat_per_index_mutex_key;
 #endif /* HAVE_PSI_INTERFACE */
 #endif /* !UNIV_HOTBACKUP */
 
-/* Compression level to be used by zlib. Settable by user. */
-UNIV_INTERN uint	page_zip_level = DEFAULT_COMPRESSION_LEVEL;
+/** Compression level to be used by zlib. Settable by user. */
+UNIV_INTERN uint	page_zip_level;
 
-/* Whether or not to log compressed page images to avoid possible
+/** Whether or not to log compressed page images to avoid possible
 compression algorithm changes in zlib. */
-UNIV_INTERN my_bool	page_zip_log_pages = false;
+UNIV_INTERN my_bool	page_zip_log_pages;
 
 /* Please refer to ../include/page0zip.ic for a description of the
 compressed page format. */

storage/xtradb/handler/ha_innodb.cc

@@ -20294,7 +20294,7 @@ 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, FALSE);
+  NULL, NULL, TRUE);
 
 static MYSQL_SYSVAR_LONG(additional_mem_pool_size, innobase_additional_mem_pool_size,
   PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,

storage/xtradb/page/page0zip.cc

@@ -2,7 +2,7 @@
 
 Copyright (c) 2005, 2016, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2012, Facebook Inc.
-Copyright (c) 2014, SkySQL Ab. All Rights Reserved.
+Copyright (c) 2014, 2017, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -83,12 +83,12 @@ UNIV_INTERN mysql_pfs_key_t		page_zip_stat_per_index_mutex_key;
 #endif /* !UNIV_INNOCHECKSUM */
 #endif /* !UNIV_HOTBACKUP */
 
-/* Compression level to be used by zlib. Settable by user. */
-UNIV_INTERN uint	page_zip_level = DEFAULT_COMPRESSION_LEVEL;
+/** Compression level to be used by zlib. Settable by user. */
+UNIV_INTERN uint	page_zip_level;
 
-/* Whether or not to log compressed page images to avoid possible
+/** Whether or not to log compressed page images to avoid possible
 compression algorithm changes in zlib. */
-UNIV_INTERN my_bool	page_zip_log_pages = false;
+UNIV_INTERN my_bool	page_zip_log_pages;
 
 /* Please refer to ../include/page0zip.ic for a description of the
 compressed page format. */