…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…
Post: Percona Server 5.1.60-13.1
December 16, 2011 By Leave a Comment
… Software Repositories). Based on MySQL 5.1.60, including all the bug fixes in it, Percona Server 5.1.60-13.1 is…-by-sort buffer cannot be more than 4GB even on 64bit architectures. With this bug fix, both the server option –myisam-sort-buffer-size and the |myisamchk| –sort-buffer-size can be set to values over 4GB on 64bit…
Post: MySQL: what read_buffer_size value is optimal ?
September 17, 2007 By 25 Comments
… wrote about rather surprising results with sort performance and today I’ve discovered even read_buffer_size selection may be less than obvious. What do we generally hear about read_buffer_size tuning ? If you… scans, with 3 runs and averaged results. MySQL 5.1.21-beta was used for tests. mysql> select count(*) from dt2 where slack…
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
…=’mrr_sort_keys=on’ (only on MariaDB 5.5) optimizer_switch=’mrr_cost_based=off’ read_rnd_buffer_size=4M (only on MySQL 5.6) mrr_buffer_size=4M…, mentioned above. Counter Name MySQL 5.5 MySQL 5.6 MySQL 5.6 w/ read_rnd_bufer_size=4M MariaDB 5.5 MariaDB 5.5 w/ mrr_buffer_size=4M Created_tmp_disk_tables…
Post: Aligning IO on a hard disk RAID – the Benchmarks
June 9, 2011 By 13 Comments
…on a Percona Server 5.0.92-87 with the following my.cnf configuration: [mysqld] datadir=/data/mysql socket=/var/run/…size = 64M thread_cache_size = 32 query_cache_size = 0 tmp_table_size = 64M key_buffer_size = 8M bulk_insert_buffer_size = 8M myisam_sort_buffer_size = 8M myisam_max_sort_file_size…
Post: MySQL Server Variables - SQL layer or Storage Engine specific.
June 8, 2006 By 14 Comments
…MySQL versions did not bother naming variables with storage engines prefix. This is why we have key_buffer, not “myisam_key_buffer…(HEAP/MEMORY). Note in 5.0 you now…sorted order (read_rnd_buffer_size). Other storage engines such as Innodb to not use this variable. sort_buffer_size Buffer used to sort…
Post: Are larger buffers always better ?
June 6, 2006 By 9 Comments
… sort_buffer_size – recently I worked with case which was running much faster with 32K sort_buffer_size, compared to 32M. The problem was memory allocation – sorting…LARGETABLE LIMIT 5 MyISAM will allocate the buffer and populate if fully when MySQL will read only 5 rows from the buffer and throw …
Post: New SpecJAppServer results at MySQL and Sun.
November 12, 2008 By Leave a Comment
… it better to disable them. The MySQL Settings are probably what is the most interesting: MySQL 5.0 Tuning in /etc/my.cnf… = 6000 read_rnd_buffer_size = 2M sort_buffer_size = 32k thread_cache = 16 query_cache_size = 0M thread_concurrency = 8 max_heap_table_size=200M log-output… so unless you have repeatable reads requirement consider using this. sort_buffer_size = 32k – It is interested how much this was really investigated…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
…-64bit x86_64 Percona Server 5.5.11 with XtraDB. Requires m1.large…mysql-inno.sock [mysqld] socket=/tmp/mysql-inno.sock default-storage-engine=INNODB innodb-buffer-pool-instances=2 innodb-buffer-pool-size…read-buffer-size=512K read-rnd-buffer-size=1M skip-host-cache skip-name-resolve sort-buffer-size=…
Post: 10+ Ways to Crash or Overload MySQL
November 13, 2007 By 20 Comments
… size is unrestricted. Note you can create tables as TEMPORARY so they would not be easily visible on file system. MyISAM Sort Buffer… 100 different tables ? This can be offset by keeping myisam_sort_buffer_size low, but then performance would suffer. Prepared Statements Number – Happily… likely cause your MySQL server to run out of file descriptors. The same is true for Partitioned tables in MySQL 5.1 Disk…
