…the testing and found that InnoDB does more IO than MyISAM when the database is cold,…joined together (Q4.1, Q4.2) but worse when small amounts of data are examined. Conclusion In some cases MyISAM is faster than…32 innodb_old_blocks_time=0 table_open_cache=2048 table_definition_cache=16384 innodb_…
Post: Is Synchronous Replication right for your app?
May 14, 2013 By 18 Comments
… a Galera cluster] a given row can’t be modified more than once per RTT This was attributed to Mark Callaghan from… semi-sync replication master] you can’t commit (at all) more than once per RTT. Applied to a Galera cluster In the…’”; } change your schema In Example 2, above, how above moving the ‘joined‘ column to the users_groups table so we don’t need…
Post: Virident vCache vs. FlashCache: Part 2
May 17, 2013 By 3 Comments
… actually produces better and more consistent performance than vCache without time-based flushing… 1G innodb_log_files_in_group = 2 innodb_purge_threads = 1 innodb_fast_…table_open_cache = 10240 max_allowed_packet = 16M binlog_cache_size = 16M max_heap_table_size = 64M sort_buffer_size = 4M join…
Post: Benchmarking Percona Server TokuDB vs InnoDB
May 7, 2013 By 32 Comments
… has more than 4x data compression on this dataset. We can easily fill TokuDB tables with 1bln…size = 4G innodb_log_files_in_group = 2 innodb_log_block_size=4096 #####plugin …table_open_cache = 2048 max_allowed_packet = 16M binlog_cache_size = 16M max_heap_table_size = 64M sort_buffer_size = 4M join…
Post: A case for MariaDB's Hash Joins
May 31, 2012 By Leave a Comment
… to MariaDB 5.5 Hash Join, Hash Join also performs worse as compared to BKA and takes 2.5x more time. While for in… the right-side table becomes costly in comparison. Block Nested Loop Join would perform better than Hash Join when you are joining two tables on a PK column such that both tables are read in…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 141 Comments
… complains about MySQL being unable to handle more than 1.000.000 (or select any other …table structure. Now if you data fully on disk (both data and index) you would need 2…joins to large tables Joining of large data sets using nested loops is very expensive. Try to avoid it. Joins to smaller tables…
Post: JOIN Performance & Charsets
October 21, 2008 By 2 Comments
… reason. Either way, the character sets used on joined columns can have a significant impact on the …ref: func rows: 1 Extra: Using where; Using index 2 rows in set, 1 warning (0.00 sec) mysql… and the key_len on both tables match. Just this simple change resulted in more than a 25% improvement in …
Post: How to find MySQL queries worth optimizing ?
September 11, 2012 By 6 Comments
… which examine one table only. What is about queries which query more than one table ? # Time: 120911 17:25:… 2 rows in set (0.00 sec) In this case we actually join 2 tables but because the access type to the tables…
Comment: Why MySQL could be slow with large tables ?
January 29, 2009 By 141 Comments
… am using mysql I had a problem with joining table where all table had a records more than 2 lakhs so when I run it from my application. it was taking too much time for execute i had a table… rows as more that 10 minituts so please anybody help me for the fetch row from multiple rows having a more than two…
Post: Innodb Table Locks
July 31, 2012 By 4 Comments
… be confused and rightfully so as Innodb table locking is a bit more complicated than traditional MyISAM table locks. Let me start with some… the query self joins the table so we observe 2 table instances (note – same table gets counted twice) in use but zero tables are locked. Innodb…
