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ShardedKV-0.10
River stage one • 3 direct dependents • 3 total dependents
1 ++
/ ShardedKV::Storage::MySQL

NAME

ShardedKV::Storage::MySQL - MySQL storage backend for ShardedKV

VERSION

version 0.10

SYNOPSIS

  use ShardedKV;
  use ShardedKV::Storage::MySQL;
  ... create ShardedKV...
  my $storage = ShardedKV::Storage::MySQL->new(
  );
  ... put storage into ShardedKV...
  
  # values are array references
  $skv->set("foo", ["bar"]);
  my $value_ref = $skv->get("foo");

DESCRIPTION

A ShardedKV storage backend that DBI and DBD::mysql to store data in a MySQL table.

Implements the ShardedKV::Storage role.

Each shard (== ShardedKV::Storage::MySQL object) is represented by a single table in some schema on some database server.

PUBLIC ATTRIBUTES

mysql_master_connector

A callback that must be supplied at object creation time. The storage object will invoke the callback whenever it needs to get a NEW mysql database handle. This means when:

  - first connecting
  - "MySQL server has gone away" => reconnect

The callback allows users to hook into the connection logic to implement things such as connection caching. If you do use connection caching, then do assert that the dbh is alive (eg. using $dbh->ping() before returning a cached connection.

table_name

The name of the table that represents this shard. Must be supplied at object creation.

key_col_name

The name of the column to be used for the key. If ShardedKV::Storage::MySQL creates the shard table for you, then this column is also used as the primary key.

There can only be one key column.

Defaults to 'keystr'.

key_col_type

The MySQL type of the key column.

Defaults to 'CHAR(16) NOT NULL'.

value_col_names

An array reference containing the names of all value columns in the shard table. Needs to contain at least one value column.

Defaults to [qw(val last_change)].

value_col_types

An array reference containing the MySQL types of each value column given in value_col_names.

Defaults to: ['MEDIUMBLOB NOT NULL', 'TIMESTAMP NOT NULL'].

extra_indexes

A string that is included verbatim after the PRIMARY KEY line of the CREATE TABLE IF NOT EXISTS statement that this class generates. This can be used to add additional indexes to the shard tables, such as indexes on the last modification (for expiration from the database, not handled by ShardedKV).

max_num_reconnect_attempts

The maximum number of reconnect attempts that the storage object should perform if the MySQL server has gone away. Reconnects are done with exponential back-off (see below).

Defaults to 5.

reconnect_interval

The base interval for reconnection attempts. Do note that exponential reconnect back-off is used, so if the base reconnect_interval is 1 second, then the first reconnect attempt is done immediately, the second after one second, the third after two seconds, the fourth after four seconds, and so on.

Default: 1 second

Can also be fractional seconds.

PRIVATE ATTRIBUTES

_mysql_connection

This is the private attribute holding a MySQL database handle (which was created using the mysql_master_connector). Do not supply this at object creation.

SEE ALSO

AUTHORS

  • Steffen Mueller <smueller@cpan.org>

  • Nick Perez <nperez@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2012 by Steffen Mueller.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.