…the key_buffer_size until, when the buffer is full, Key_reads/Uptime reduces to a number you’re comfortable with. Set key_buffer_size really big…your IO system’s capabilities. MySQL doesn’t have good instrumentation for scientifically choosing a key_buffer_size setting, but there are many …
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
…=0 partition=ON port=3306 read-buffer-size=512K read-rnd-buffer-size=1M skip-host-cache skip-name-resolve sort-buffer-size=512K sql-mode=STRICT_TRANS…-size=32 thread-stack=256K tmp-table-size=64M transaction-isolation=READ-COMMITTED user=mysql wait-timeout=86400 To be continued You can now set…
Post: MySQL Server Memory Usage
May 17, 2006 By 21 Comments
…buffer_size, query_cache_size. If you’re using MyISAM seriously you can also add the size of Operation System cache you would like MySQL…as much as read_buffer_size, sort_buffer_size, read_rnd_buffer_size, tmp_table_size of memory… read_buffer,sort_buffer, tmp_table_size etc Many variabes can be set…
Post: Can we improve MySQL variable handling ?
February 18, 2012 By 8 Comments
… way to read it: mysql> set global sort_buffer_size=DEFAULT; Query OK, 0 rows affected (0.00 sec) mysql> select @@global.sort_buffer_size; +—————————+ | @@global.sort_buffer_size | +—————————+ | 2097152 | +—————————+ 1 row in set…
Post: Helgrinding MySQL with InnoDB for Synchronisation Errors, Fun and Profit
November 24, 2011 By 2 Comments
… much introduction, especially to the MySQL server developers. The Valgrind Memcheck…. These are buffer pool statistics counters: number of read, written, evicted, … This conflicts with a previous read of size 8 by thread #14 ==9090== … mutex_get_waiters/mutex_set_waiters above and similar cases…
Post: MySQL Server Variables - SQL layer or Storage Engine specific.
June 8, 2006 By 14 Comments
…read_buffer_size, read_rnd_buffer_size – Variables used as read buffer for MyISAM tables for Full Table Scan (read_buffer) and for reading rows in sorted order (read_rnd_buffer_size…
Post: How much memory can MySQL use in the worst case?
February 12, 2009 By 17 Comments
…: “It is possible that mysqld could use up to key_buffer_size + (read_buffer_size + sort_buffer_size)*max_connections”. This was never true — not even when… you set sort_buffer_size to 128K — I can quite well connect and say “set @@sort_buffer_size := 1 * 1024 * 1024 * 1024;” and my sort_buffer_size is… for user locks! I set my max_allowed_packet bigger and ran the following on my laptop: mysql> set @a := repeat(‘a’, 1024…
Post: Are larger buffers always better ?
June 6, 2006 By 9 Comments
… values. read_buffer_size and read_rnd_buffer_size – These are buffers used by MyISAM to perform reads, in different scenarios. So should we go ahead and set them… 5 MyISAM will allocate the buffer and populate if fully when MySQL will read only 5 rows from the buffer and throw away the…
Post: Impact of the sort buffer size in MySQL
October 25, 2010 By 8 Comments
… parameter sort_buffer_size is one the MySQL parameters that is far from obvious to adjust. It is a per session buffer that is…. After reading a post from Ronald Bradford (here), I decide to verify and benchmark performance while varying the size of the sort_buffer… 1 1000` do START=`date +%s.%N` OUT=`mysql -e “set session sort_buffer_size=32*1024*$i;select * from sorttest order by data…
Post: MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark
March 11, 2013 By 7 Comments
…_DATA_READS | 191581 | | INNODB_PAGES_READ | 191570 | | INNODB_ROWS_READ | 910844 | +—————————————+—————-+ 10 rows in set (0.01 sec) mysql> select sq.*, pages / ((@@innodb_buffer_pool_size / 16384…_DATA_READS | 186417 | | INNODB_PAGES_READ | 186406 | | INNODB_ROWS_READ | 910844 | +—————————————+—————-+ 10 rows in set (0.00 sec) mysql> select sq.*, pages / ((@@innodb_buffer_pool_size / 16384…
