InnoDB: Inserting data of varying record lengths into an InnoDB table that used compression could cause the server to halt with an error. (Bug #14554000, Bug #13523839, Bug #63815, Bug #12845774, Bug #61456, Bug #12595091, Bug #61208)

InnoDB: Under heavy load of concurrent DML and queries, an InnoDB table with a unique index could return nonexistent duplicate rows to a query. (Bug #14399148, Bug #66134)

InnoDB: Deleting from an InnoDB table containing a prefix index, and subsequently dropping the index, could cause a crash with an assertion error. (Bug #13807811)

InnoDB: The error message was improved for the case where an UPDATE failed because the row included several BLOB values greater than 768 bytes each, causing the size of a row to exceed half the page size. The old message, was misleading; it suggested using BLOBs, when the 768-byte prefix for each BLOB column was the cause of the limit error:

Error Code 1118: Row size too large. The maximum row size for the used table 
type, not counting BLOBs, is 8126. You have to change some columns to TEXT or 
BLOBs

A workaround for the problem was to create the table with the ROW_FORMAT=DYNAMIC or ROW_FORMAT=COMPRESSED clause, which is now suggested in the message. (Bug #13453036, Bug #63507)

InnoDB: Certain information_schema tables originally introduced in MySQL 5.6 are now also available in MySQL 5.5 and MySQL 5.1: INNODB_BUFFER_PAGE, INNODB_BUFFER_PAGE_LRU, and INNODB_BUFFER_POOL_STATS. (Bug #13113026)

InnoDB: When a SELECT ... FOR UPDATE, UPDATE, or other SQL statement scanned rows in an InnoDB table using a < or <= operator in a WHERE clause, the next row after the affected range could also be locked. This issue could cause a lock wait timeout for a row that was not expected to be locked. The issue occurred under various isolation levels, such as READ COMMITTED and REPEATABLE READ. (Bug #11765218)

Partitioning: The buffer for the row currently read from each partition used for sorted reads was allocated on open and freed only when the partitioning handler was closed or destroyed. For SELECT statements on tables with many partitions and large rows, this could cause the server to use excessive amounts of memory.

This issue has been addressed by allocating buffers for reads from partitioned tables only when they are needed and freeing them immediately once they are no longer needed. As part of this fix, memory is now allocated for reading from rows only in partitions that have not been pruned (see Partition Pruning). (Bug #13025132)

References: See also Bug #11764622, Bug #14537277.

Replication: In master-master replication with --log-slave-updates enabled, setting a user variable and then performing inserts using this variable caused the Exec_master_log_position column in the output of SHOW SLAVE STATUS not to be updated. (Bug #13596613)

The libmysqlclient_r client library exported symbols from yaSSL that conflict with OpenSSL. If a program linked against that library and libcurl, it could crash with a segmentation fault. (Bug #14068244)

Small sort_buffer_size values could result in a server crash. (Bug #14111180)

The argument for LIMIT must be an integer, but if the argument was given by a placeholder in a prepared statement, the server did not reject noninteger values such as '5'. (Bug #13868860)

Access to INFORMATION_SCHEMA tables through a view could leak memory. (Bug #13734987)

A query for a FEDERATED table could return incorrect results when the underlying table had a compound index on two columns and the query included an AND condition on the columns. (Bug #12876932)

Adding a LIMIT clause to a query containing GROUP BY and ORDER BY could cause the optimizer to choose an incorrect index for processing the query, and return more rows than required. (Bug #54599, Bug #11762052)

mysqlbinlog did not accept input on the standard input when the standard input was a pipe. (Bug #49336, Bug #11757312)

The argument to the --ssl-key option was not verified to exist and be a valid key. The resulting connection used SSL, but the key was not used. (Bug #62743, Bug #13115401)

In debug builds, an InnoDB assertion was overly aggressive about prohibiting an open range. (Bug #66513, Bug #14547952)