… can’t use mysql_num_rows() and mysql_data_seek() if you use this method but this is told in PHP manual and… hint if you need to release table locks early. It comes at cost of creating temporary table though which can be quite high… do INSERT … SELECT to the temporary table with auto_increment column and fetch data from this table using auto increment column ranges instead…
Post: Are PHP persistent connections evil ?
November 12, 2006 By 31 Comments
As you probably know PHP “mysql” extension supported persistent connections but they were disabled in new “…, using temporary tables or having other significant memory requirements you may well out of memory and get crash or have MySQL starting to…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
… data from 1988 to 2010′; mysql> use ontime1; Database changed mysql> show table status like ‘ontime_fact’G …. This frees disk to use on-disk temporary storage for hash joins and other background … shards (adjust to your number of nodes) php genconfig 20 > shards.ini Running the test…
Comment: Are PHP persistent connections evil ?
December 28, 2009 By 31 Comments
… far too many client processes (think mod_php); forgetting to unlock tables and not cleaning up temporary tables; poor use of session variables, etc… mpm (up to 3000 threads), with fastCGI + PHP (1 process, 24 children), connecting to mysql via Unix sockets with persistent connections. I…
Comment: Using delayed JOIN to optimize count(*) and LIMIT queries
April 16, 2007 By 22 Comments
…”lower” characters ! Yes I often use this too, in MySQL and in Postgres, it is just one of … it : – first query the active table and store the results in a temporary table. – since i use ORDER BY + LIMIT… temp table and fetch it – I perform all my joins from the temp table (no freaky IN() from php) …
Post: GROUP_CONCAT useful GROUP BY extension
September 4, 2006 By 43 Comments
… useful? For example to get PHP array without looping inside PHP: Table: CREATE TABLE services ( id INT UNSIGNED … in PHP: old way: with group_concat: This should work faster, as we remove loop from PHP to MySQL … with joins, but sometimes we need the temporary ids in clients code, for example to …
Comment: How much overhead is caused by on disk temporary tables
April 30, 2008 By 26 Comments
…). The only problem I have run into is creating temporary InnoDB table (file per table setting), because tmpfs cannot do IO_DIRECT. It… innoDB table. However, despite these warnings, I think the result is OK and the table is created (see http://bugs.mysql.com/bug.php…
Comment: How Percona diagnoses MySQL server stalls
March 9, 2011 By 6 Comments
…MySQL would go (once a week) into a deadlock collapsing the whole application cluster, two apache webservers (mod_php…hundreds) Doing many tests at the end the temporary solution was to shut down 14 out… one key cache for each high concurrency table and preloading indexes helped lower the contention….
