Asynchronous Prefetch Database Query Cache

Categories

Database Drivers
Performance and Scalability

Component ID

2382953

Component name

Asynchronous Prefetch Database Query Cache

Component type

module

Maintenance status

Actively maintained

Development status

Under active development

Component security advisory coverage

not-covered

Downloads

10433

Component created

Component changed

Component body

A pretty darn quick cache. Uses asynchronous connections & prefetching to speed up cache calls & eliminate deadlocks & metadata locks on the cache tables.

Requirements

MySQL 5.5+, PHP 5.3+, and the mysqlnd driver.

Features & Benefits

  • Eliminates deadlocks & metadata locks for all cache tables.
  • Faster page load times for logged in and anonymous users due to cache prefetching.
  • Outputs query information to the devel query log. Will output prefetch info as well.
  • Better handing of the minimum cache lifetime; does smarter garbage collection of the cache bins. Purges caches based on individual records' timestamps instead of just using the expire column, the created column is used as well.
  • Changes the collation of cache tables to utf8_bin. Using the utf8_bin collation is faster and more accurate when matching cache ids since no unicode normalization is done to cache query conditions. D8 backport of (#2352207: Database cache backend does not treat cid as case sensitive).
  • Changes the semaphore table to use the MEMORY engine if using MySQL 5.5 or lower. This will speed up writes to the lock table for older versions of MySQL.
  • Writes to the watchdog table from the dblog module are done using an async query.
  • Session initialization is done with 1 query instead of 2. Session writes use async queries.
  • Configurable, per bin deflate compression of the data blob resulting in smaller cache tables in the database and faster network transfers if MySQL is on a different box.

Installation

The quick and easy way to set this up is to install the module and go to the status report page admin/reports/status. Works with MySQL only at this point.

Below is what you'll typically need to add to your settings.php file.

$databases['default']['default']['init_commands']['isolation'] = "SET SESSION tx_isolation='READ-COMMITTED'";
$databases['default']['default']['init_commands']['lock_wait_timeout'] = "SET SESSION innodb_lock_wait_timeout = 20";
$databases['default']['default']['init_commands']['wait_timeout'] = "SET SESSION wait_timeout = 600";
$conf['cache_backends'][] = 'sites/all/modules/apdqc/apdqc.cache.inc';
$conf['cache_default_class'] = 'APDQCache';
$conf['lock_inc'] = 'sites/all/modules/apdqc/apdqc.lock.inc';
$conf['session_inc'] = 'sites/all/modules/apdqc/apdqc.session.inc';

Known Issues

The current version of Parallels Plesk does not support php-mysqlnd. It should be fixed in the next release of that software.

Similar Modules

https://www.drupal.org/project/mysql_async
https://www.drupal.org/project/adbc
https://www.drupal.org/project/cache_heuristic
https://www.drupal.org/project/lcache

Component url

https://www.drupal.org/project/apdqc