June 18, 2013

Post: Benchmarking Percona Server TokuDB vs InnoDB

… suit) with some roll-up aggregation, which should produce updates in-place (I will use INSERT .. ON DUPLICATE KEY UPDATE statements…=insert_roll.lua –oltp-table-size=10000 –mysql-user=root –oltp-tables-count=32 –mysql_table_engine=tokudb –oltp_auto_inc=on…_max_sort_file_size = 10G #myisam_max_extra_sort_file_size = 10G myisam_repair_threads = 1 myisam_recover socket=/var/lib/mysql/mysql.sock…

Post: Virident vCache vs. FlashCache: Part 2

… using the base HDD MySQL configuration for purposes of comparison. Given the apparent differences in time-based flushing in vCache and FlashCache, both…­-time=7200 ­­–max­-requests=0 ­­–percentile=95 ­­\ –mysql­-user=root –mysql­-socket=/tmp/mysql.sock ­­–mysql­-table­-engine=innodb ­­\ –oltp­-read­-only=off run…_size = 4M bulk_insert_buffer_size = 8M myisam_sort_buffer_size = 8M myisam_max_sort_file_size = 10G myisam_repair_threads = 1…

Comment: Virident vCache vs. FlashCache: Part 1

… controller such that now it becomes the bottleneck. Also, keep in mind that while SSDs are a lot faster than regular… Micron PCIe card, not Virident, but there’s a comparison in TPCC-MySQL performance between that card and a traditional SSD – the… FlashCache/vCache approach with this sort of use case, I’m effectively allowing my database to run in memory (not actual RAM…

Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5

in MariaDB 5.5 and not in MySQL 5.6, is that because of a bug in MySQL 5.6 code? As MRR was used in both MySQL 5.6… is in-memory, in fact MRR adds extra sorting overhead which means that the queries are just a bit slower as compared to MySQL

Post: MySQL 5.5 and MySQL 5.6 default variable values differences

… ON by default in MySQL 5.6 but you can see many options can be scaled down compared to MySQL 5.5 default… are less than 200 tables in this system. innodb_stats_on_metadata is disabled by default in MySQL 5.6 Welcome to much…,index_merge_sort_union=on,index_merge_intersection=on,engine_condition_pushdown=on 1 row in set (0.00 sec) mysql [localhost] {msandbox…

Post: MySQL Indexing Best Practices: Webinar Questions Followup

…’ The other thing you need to consider is string comparison in MySQL is case insensitive by default while hash comparison will be… can one have optimized indexes and sorting in such a scenario, since inequality ends index usage. Actually in this case index on (A… this column. This works because by scanning data in index order MySQL gets data in already sorted order and looks at “one group at…

Post: InnoDB Full-text Search in MySQL 5.6 (part 1)

… full-text search in MySQL 5.6 (part 1) in MySQL 5.6 is syntactically identical to MyISAM full-text search, in the sense that… files in our database directory: -rw-rw—-. 1 mysql mysql 8632 Feb 20 15:54 dir_test_innodb.frm -rw-rw—-. 1 mysql mysql 213909504… constraint violations unless you also do something to provide some sort of sequence value for that column, whether as an auto…

Post: Fun with the MySQL pager command

…is wrong. Let’s retry: # Rewritten query – correct mysql> SELECT … 32a1894d773c9b85172969c659175d2d – 1 row in set (0.17 sec) Checksums are identical, …status: mysql> pager awk -F ‘|’ ‘{print $6}’ | sort | uniq -c | sort -r PAGER set to ‘awk -F ‘|’ ‘{print $6}’ | sort | uniq -c | sort -r’ mysql> …

Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5

… available in both MySQL 5.6 and MariaDB 5.5. You can read more about BKA in MySQL 5.6 here and BKA in MariaDB 5.5 here. However, MariaDB 5.5 has one additional optimization that is used in… scan, the secondary key on col1 would be sorted by col1 i.e. in index order and then the lookup will be…