New Features
Percona Server has implemented support for per-column VARCHAR/BLOB compression for the XtraDB storage engine. This also features compression dictionary support, to improve compression ratio for relatively short individual rows, such as JSON data.
A new TokuDB tokudb_dir_per_db option has been introduced to address two TokuDB shortcomings, the renaming of data files on table/index rename, and the ability to group data files together within a directory that represents a single database. This feature is disabled by default.
Bugs Fixed
After fixing bug #1540338, system table engine validation check is no longer skipped for tables that don’t have an explicit ENGINE clause in a CREATE TABLE statement. If MySQL upgrade statements are replicated, and slave does not have the MyISAM set as a default storage engine, then the CREATE TABLE mysql.server statement would attempt to create an InnoDB table and fail because mysql_system_tables.sql script omitted explicit engine setting for this table. Bug fixed #1600056.
Audit Log Plugin malformed record could be written after audit_log_flush was set to ON in ASYNC and PERFORMANCE modes. Bug fixed #1613650.
A race condition between HandlerSocket and server shutdown could lead to a server stall if shutdown was issued immediately after HandlerSocket startup. Bug fixed #1617198.
HandlerSocket could access freed memory on startup. Bug fixed #1617998.
Workloads with statements that take non-transactional locks (LOCK TABLES, global read lock, and similar) could have caused deadlocks when running under Thread Pool with high priority queue enabled and thread_pool_high_prio_mode set to transactions. Fixed by placing such statements into the high priority queue even with the above thread_pool_high_prio_mode setting. Bugs fixed #1619559 and #1374930.
Fixed memory leaks in Audit Log Plugin. Bug fixed #1620152 (upstream #71759).
Server could crash due to a glibc bug in handling short-lived detached threads. Bug fixed #1621012 (upstream #82886).
QUERY_RESPONSE_TIME_READ and QUERY_RESPONSE_TIME_WRITE were returning QUERY_RESPONSE_TIME table data if accessed through a name that is not full uppercase. Bug fixed #1552428.
Fixed memory leaks in HandlerSocket. Bug fixed #1617949.
KILL QUERY was not behaving consistently and it would hang in some cases. Bug fixed #1621046 (upstream #45679).
Cipher ECDHE-RSA-AES128-GCM-SHA256 was listed in the list of supported ciphers but it wasn’t supported. Bug fixed #1622034 (upstream #82935).
Successful doublewrite recovery was showed as a warning in the error log. Bug fixed #1622985.
Variable query_cache_type couldn’t be set to 0 if it was already set to that value. Bug fixed #1625501 (upstream #69396).
LRU manager thread could run too long on a server shutdown, causing a server crash. Bug fixed #1626069.
tokudb_default was not recognized by Percona Server as a valid row format. Bug fixed #1626206.
InnoDB ANALYZE TABLE didn’t remove its table from the background statistics processing queue. Bug fixed #1626441 (upstream #71761).
Upstream merge for #81657 to 5.6 was incorrect. Bug fixed #1626936 (upstream #83124).
Fixed multi-threaded slave thread leaks that happened in case of thread create failure. Bug fixed #1619622 (upstream #82980).
Shutdown waiting for a purge to complete was undiagnosed for the first minute. Bug fixed #1616785.
Unnecessary InnoDB change buffer merge attempts are now skipped upon reading disk pages of non-applying types. Bug fixed #1618393 (upstream #75235).
Other bugs fixed: #1614439, #1614949, #1616392 (upstream #82798), #1624993 (#736), #1613647, #1626002 (upstream #83073), #904714, #1610102, #1610110, #1613663, #1613728, #1613986, #1614885, #1615959, #1615970, #1616333, #1616404, #1616768, #1617150, #1617216, #1617267, #1618478, #1618811, #1618819, #1619547, #1619572, #1620583, #1622449, #1622456, #1622977, #1623011, #1624992 (#1014), #1625176, #1625187, #1626500, #1628417, #964, and #735.
