… constantly referring to the amazing MySQL manual, especially the option and variable reference table. But …retry_countblogpercona.commanual net_write_timeoutblogpercona.commanual newblogpercona.commanual no_defaultsblogpercona.commanual Not_flushed_delayed_rowsblogpercona.commanual oldblogpercona….
Post: When the subselect runs faster
March 18, 2010 By 9 Comments
… to find rows. This is sensible strategy if there is no LIMIT, however it is poor chose if there is one – it…’||col1=’B')) ORDER BY id DESC LIMIT 20 OFFSET 0; In this case we forcing MySQL to do retrieve rows in sorted order… override MySQL index choice: mysql> explain select * from table FORCE INDEX(PRIMARY) where (col1=’A'||col1=’B') order by id desc limit 20 offset…
Post: 10+ Ways to Crash or Overload MySQL
November 13, 2007 By 20 Comments
… offset by keeping myisam_sort_buffer_size low, but then performance would suffer. Prepared Statements Number – Happily now there is a limit… MySQL does not have much of resource utilization control you can simply run heavy queries to get MySQL Server barely functional. The limits… unknown to MySQL Team. What I’m trying to do is pretty much explain the issue so there is no misunderstandings on…
Comment: To SQL_CALC_FOUND_ROWS or not to SQL_CALC_FOUND_ROWS?
August 29, 2007 By 57 Comments
…is not true, in “EXPLAIN SELECT SQL_NO_CACHE count(*) FROM count_test WHERE b = 666;”, count… count_test WHERE b = 999 ORDER BY c LIMIT 5;”, mysql uses index to determine number of rows to examine… that accept a dynamic sql query, an offset and a limit then use prepared statement to execute query …
Post: How InnoDB handles REDO logging
February 3, 2011 By 19 Comments
…no, operation code, data> This translates into operations such as <0, 2600, ‘insert’, ‘after record at offset…all, your transaction will never complete. Both the MySQL configuration and hardware will affect the speed … the InnoDB limit of 4G. As a side effect of logging there is no need to …
Post: Is your server's performance about to degrade?
May 18, 2010 By 13 Comments
… — here’s the magic — the byte offset of the worst performer in the …Quit; and Statistics; and similar no-tables, no-storage-engines queries are varying …and that’s where improvements to the MySQL source code are necessary. But in… the server isn’t pushing the limits of performance doesn’t mean it…
Post: A case for MariaDB's Hash Joins
May 31, 2012 By Leave a Comment
… the size of the buffer ‘join_buffer_space_limit‘. This variable controls the maximum allowed size of …of the secondary key. Even though MySQL 5.6 uses MRR to offset the effect of random access of PK… response time when you are joining tables with no indexes on the join condition (Full Join). The …
Comment: MySQL Server Memory Usage
December 20, 2012 By 21 Comments
…mysql configuration (We are having only 1 mysql server, no replication setup) [mysqld] datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock user=mysql…mysql,test #replicate_do_db=crmdb #replicate_do_db=newcrmdb #auto-increment-increment = 3 #auto-increment-offset…8M query_cache_limit = 254M query_…
Post: What exactly is read_rnd_buffer_size
July 24, 2007 By 4 Comments
… row pointers together with key value – which are offsets for MyISAM and primary key values for Innodb…LIMIT 10 it is unlikely to help as MySQL will stop fetching rows by pointers quickly For me this means since MySQL… buffer and sort file so there would be no need for read_rnd_buffer, if the selected…
Comment: 5.0.77 / 5.0.82 -build16 Percona binaries
June 19, 2009 By 4 Comments
…MySQL-percona-b16-5.0… at 5081. Hunk #11 succeeded at 6537 (offset -12 lines). 1 out of 11 hunks …OPT_SECURE_FILE_PRIV, And there is no OPT_PROFILING_USE_GETRUSAGE in mysqld.cc…; + extern ulong srv_io_pattern_size_limit; /*——————————————-*/ extern ulint srv_n_rows_inserted; …
