… see MySQL memory consumption plotted. I use “VSZ” columns from “ps…and not): mysql> select * from information_schema.global_temporary_tables \G *************************** 1. row …swapped out and when never needed again. So if you see swap file used space gradually growing and there are “swap…
Post: PHP Large result sets and summary tables.
July 6, 2007 By 8 Comments
…and was swapping development server which had just 4GB of Ram (and plenty of swap space) like crazy. Why ? Because by default mysql_query uses mysql… run mysql_query , mysql_fetch_row simply reads data from memory and …increment column and fetch data from this table using auto increment column ranges…
Post: How much overhead is caused by on disk temporary tables
August 16, 2007 By 26 Comments
…and also by the data which needs to be put to temporary tables – BLOB/TEXT columns… 10 rows in set (27 min 5.51 sec) VMSTAT: procs ———–memory———- —swap…rows in set ( 3.88 sec) Wow. This is great difference even from our best MyISAM results. For 4M of rows mysql…
Post: Faster Point In Time Recovery with LVM2 Snaphots and Binary Logs
February 23, 2012 By Leave a Comment
…rows affected (0.15 sec) mysql> drop table salaries; — Ooops! Query OK, 0 rows affected (0.49 sec) mysql> alter table employees add column…
Post: Implementing efficient counters with MySQL
July 1, 2007 By 16 Comments
…and “counter” columns. Using separate table for updates already solves the problem in a lot of cases, and…just mentioned would have approximately 20 byte rows even for Innodb tables which makes …into one and process and truncate another. MySQL offers atomic RENAME TABLE call which can be used to swap …
Post: Impact of the sort buffer size in MySQL
October 25, 2010 By 8 Comments
…column without an index: CREATE TABLE `sorttest` ( `data` char(30) DEFAULT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 and I inserted 100k rows… the whole process, the computer never swapped and I pre-warmed the file cache … least for the Linux, glibc and MySQL versions I used and for the test I did, …
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 17 Comments
…this with care: you MUST use row-based binlogging and replication, and remember that the execution is not serializable…. decide (incorrectly) to swap out MySQL. There are two solutions here. Memlock and O_DIRECT. Memlock is …: it can be used if the columns are the first columns in an index. I think …
Comment: MySQL Server Memory Usage
September 1, 2006 By 18 Comments
…% available, MPM and dual…collations’, ’176788′ ‘Com_show_column_types’, ’0′ ‘… ‘Sort_range’, ’56479689′ ‘Sort_rows‘, ’1344092495′ ‘Sort_scan’, ‘… in_c Swap: 4194224k av…mysql.sock pid-file=/var/run/mysql/mysql.pid datadir=/db/disk2/mysql/data log-bin=/var/log/mysql/log log-slow-queries=/var/log/mysql…
Post: Memory allocation in Stored Function
August 26, 2007 By 8 Comments
… time ago I had task to update string column in table with 10mil+ rows, and, as the manipulation was non-trivial, I decided… check only select: mysql> select avg(length(hello(name))) from testf; and here is vmstat 5 output: procs ———–memory———- —swap– —–io—- –system– —-cpu…
