This release is based on MySQL 5.7.20 and includes all the bug fixes in it. Percona Server 5.7.20-18 is now the current GA release in the 5.7 series. All software developed by Percona is open-source and free. Details of this release can be found in the 5.7.20-18 milestone on Launchpad.
innodb_ft_ignore_stopwordsvariable has been implemented which controls whether InnoDB Full-Text Search should ignore stopword list when building/updating an FTS index. This feature is also fixing bug #1679135 (upstream #84420).
MEMORYtables requires all the key columns to come before any
BLOBcolumns. This requirement however was not enforced, allowing creating MEMORY tables in unsupported column configurations, which then crashed or lose data in usage. Bug fixed #1731483.
CREATE/DROP TEMPORARY TABLEstatements were forbidden incorrectly in transactional contexts, including function and trigger calls, even when they required no binary logging at all. Bug fixed #1711781.
ANALYZE TABLEwhile a long-running query is accessing the same table in parallel could lead to a situation where new queries on the same table are blocked in a
Waiting for table flushstate. Fixed by stopping
ANALYZE TABLEflushing affected InnoDB and TokuDB tables from the table definition cache. Bug fixed #1704195 (upstream #87065).
CREATE TABLE ... LIKE ...did not use source
row_formaton target TokuDB table. Bug fixed #76.
ALTER TABLEwas run. Bug fixed #35.
innodb_flush_log_at_trx_commitbehavior. Two implement this feature
rocksdb_concurrent_preparevariables have been implemented.
rocksdb_force_compute_memtable_stats_cachetimevariable has been implemented that cane be used to specify how long the cached value of memtable statistics should be used instead of computing it every time during the query plan analysis.
rocksdb_large_prefixvariable has been implemented which, when enabled, allows index key prefixes longer than 767 bytes (up to 3072 bytes). This option mirrors the innodb_large_prefix The values for this variable should be the same between master and slave.
rocksdb_max_background_jobsvariable has been implemented to replace
rocksdb_max_background_flushesvariables. This variable specifies the maximum number of background jobs. It automatically decides how many threads to allocate towards flush/compaction. It was implemented to reduce the number of (confusing) options users and can tweak and push the responsibility down to RocksDB level.
rocksdb_sim_cache_sizevariable has been implemented to enable the simulated cache. This can be used to figure out the hit/miss rate with a specific cache size without changing the real block cache.
rocksdb_ignore_unknown_optionsvariable has been implemented, which when enabled (default) allows RocksDB to receive unknown options and not exit.
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