… distribution $C, $PAD = random_string() BEGIN INSERT INTO sbtest (id, k, c, pad) VALUES ($ID, $K, $C, $PAD); INSERT INTO sbtest_r10 (id… workload produces SEQUENTIAL inserts into Primary Key, that this is quite suitable for InnoDB, and in it we have random inserts into SECONDARY…-rel30.2-500.Linux.x86_64/lib/mysql/libjemalloc.so [mysqld] gdb datadir=/mnt/data/mysql #for SSD innodb_flush_neighbor_pages = none…
Post: Is disk Everything for MySQL Performance ?
April 25, 2008 By 7 Comments
…data archive storage. On BoardReader for example we’re limited by space and how much data we can comfortably put in MySQL… all search heavy lifting we only need to insert new data and fetch few rows to show search… spindles – So your hard drive can do 200 random reads per second and your SSD drive can…
Post: How InnoDB handles REDO logging
February 3, 2011 By 19 Comments
… ensuring that in the event of a MySQL crash the data will still be consistent, however in the … which check-pointing can occur. In order to insert a new record in the transaction log, InnoDB … changes at commit, therefore what would be a random write is translated into a much faster sequential write…
Post: To UUID or not to UUID ?
March 13, 2007 By 28 Comments
… conclusions. Data size is very small. What is the biggest problem with UUID ? It is the fact inserts are going in random locations… key value – if you would use integer key and insert data in random order you would have the same problems. In fact if… however completely separate problem which can be fixed in MySQL 5.1 Data Clustering This again applies to Innodb tables aspect of…
Post: Aligning IO on a hard disk RAID – the Benchmarks
June 9, 2011 By 13 Comments
….cnf configuration: [mysqld] datadir=/data/mysql socket=/var/run/mysqld/mysqld.sock innodb_file_per_table = true innodb_data_file_path = ibdata1:10M… intensive workloads where there’s a lot of data being modified, inserts are done to random positions (not consecutive PK causing page splits…
Post: Innodb row size limitation
April 7, 2011 By 12 Comments
I recently worked on a customer case where at seemingly random times, inserts would fail with Innodb error 139. This is a… TEXT, PRIMARY KEY (id) ) Engine=InnoDB; Now you insert some test data into it: mysql> INSERT INTO example -> VALUES ( ->Â Â NULL, ->Â Â… depends a lot on the type of data you’re inserting (hint: the more random your data is, the worse compression will work). Something…
Post: MySQL File System Fragmentation Benchmarks
March 21, 2008 By 28 Comments
… of tables and does specified number of inserts going to random tables. I used default MySQL settings for MyISAM (table_cache=64) and… learn from these results – Concurrent growth of many tables causes data fragmentation and affects table scan performance nadly – MyISAM suffers worse…
Post: Improved InnoDB fast index creation
November 6, 2011 By 4 Comments
…sec) mysql> INSERT INTO t(c) VALUES (RAND()); Query OK, 1 row affected (0.00 sec) mysql> INSERT INTO t…, because it does not have to do random disk seeks to fetch secondary index pages …Avg_row_length: 29 Data_length: 125452288 Max_data_length: 0 Index_length: 278839296 Data_free: 1838153728 Auto_…
Post: ALTER TABLE: Creating Index by Sort and Buffer Pool Size
June 27, 2012 By 4 Comments
… build by insertion as insertions happen in the “end” of index tree. I’ve updated column to have bunch of long random strings… table which would look as following in terms of data and index size: mysql> show table status like “sbtest” \G *************************** 1. row… in the real world. Working with indexing, such as inserting data in random order can become very slow when index does not fit…
Comment: MySQL Server Variables - SQL layer or Storage Engine specific.
June 8, 2006 By 14 Comments
…insert buffer can speed things significantly for bulk inserts by avoiding random IO for updating index. …file but in practice overhead is minimal: mysql> load data infile ‘/tmp/z.txt’ into table …Warnings: 0 mysql> truncate table two; Query OK, 0 rows affected (0.20 sec) mysql> insert into two select…
