… –num-threads=32 –test=tests/db/oltp.lua –oltp_tables_count=32 \ –oltp-table-size=10000000 –rand-init=on –report-interval… = 50 wait_timeout = 120 max_connections = 5000 max_prepared_stmt_count=500000 max_connect_errors = 10 table_open_cache = 10240 max…
Post: Benchmarking Percona Server TokuDB vs InnoDB
May 7, 2013 By 32 Comments
….lua –oltp-table-size=10000 –mysql-user=root –oltp-tables-count=32 –mysql_table_engine=tokudb –oltp_auto_inc=on –max… = 3306 back_log = 50 max_connections = 2000 max_prepared_stmt_count=500000 max_connect_errors = 10 table_open_cache = 2048 max…
Post: Finally. How to verify if all MySQL records were recovered
April 25, 2013 By Leave a Comment
… number of records the page stores. Obviously it doesn’t count any deleted records. The second method to confirm how many… are in the page is to follow records pointers – and count them. As you might know, records inside an InnoDB page…
Comment: Fun with the MySQL pager command
May 1, 2013 By 6 Comments
… show processlist trick is not quite right: it is also counting the header lines. I modified it as follows: mysql> pager…
Post: Is your MySQL buffer pool warm? Make it sweat!
April 16, 2013 By 6 Comments
… –query-log-stdin –dispatcher-plugin thread-pool –thread-pool-threads-count 100 –session-init-query \”set innodb_fake_changes=1\” > /var…
Comment: Using index for ORDER BY vs restricting number of rows.
April 11, 2013 By 8 Comments
… of follow and order by follow。 I wrote: SELECT follow,count(*) AS NUM FROM wp_fans GROUP BY follow order by…
Post: Percona Playback 0.6 for MySQL now available
April 9, 2013 By 1 Comment
… MySQL database servers. This feature introduces new –thread-pool-threads-count option, which can be used to specify the number of…
Post: Understanding the maximum number of columns in a MySQL table
April 8, 2013 By 5 Comments
…*FCOMP+288+ n_length+int_length+com_length > 65535L || int_count > 255) { my_message(ER_TOO_MANY_FIELDS, ER(ER_TOO…
Comment: SimCity outages, traffic control and Thread Pool for MySQL
March 22, 2013 By 16 Comments
… single-threaded libevent and had to serialize on LOCK_thread_count or some other global mutex to do its work.
Post: COUNT(*) vs COUNT(col)
April 10, 2007 By 45 Comments
…=latin1 mysql> select count(*) from fact; +———-+ | count(*) | +———-+ | 7340032 | +———-+ 1 row in set (0.00 sec) mysql> select count(val) from fact; +————+ | count(val) | +————+ | 7216582… is why it is able to instantly answer COUNT(*) and COUNT(val2) queries, but not COUNT(val). Why ? Because val column is not…
