pt-online-schema-change

Spec sheet

Purpose

pt-online-schema-change alters MySQL table structures without blocking reads or writes by building and populating a copy of the table, then replacing the original.Read 8 Oct 2026 · docs.percona.com

Intended users

Percona describes the Toolkit as advanced open-source command-line tools for DBAs and database operations.Read 8 Oct 2026 · percona.com

Support

Percona says its Community Forum service is free and response times vary with the complexity of the question.Read 8 Oct 2026 · docs.percona.com

License

The program is free software under either the GNU General Public License version 2 or the Perl Artistic License.Read 8 Oct 2026 · docs.percona.com

Founded

2006Read 28 Sep 2026 · docs.percona.com

Chunked copying

It copies rows in small chunks and uses triggers to apply changes made to the original table during the copy.Read 8 Oct 2026 · docs.percona.com

Cluster support

For Percona XtraDB Cluster 5.5.28-23.7 and newer, only InnoDB tables can be altered and wsrep_OSU_method must be TOI.Read 8 Oct 2026 · docs.percona.com

Execution safety

The tool does not modify a table unless the --execute option is specified; --dry-run and --execute are mutually exclusive.Read 8 Oct 2026 · docs.percona.com

Foreign-key handling

Foreign keys that reference the table require a specified foreign-key method, and their handling introduces additional risk.Read 8 Oct 2026 · docs.percona.com

Install platforms

Percona documents package-manager installation for Debian or Ubuntu and RHEL or CentOS, plus package downloads and a tar.gz release.Read 8 Oct 2026 · docs.percona.com

Installation telemetry

The installer stores an instance UUID for toolkit usage statistics and states that no other information is gathered for that purpose.Read 8 Oct 2026 · docs.percona.com

Key requirement

In most cases, the table needs a PRIMARY KEY or UNIQUE INDEX for the tool to operate.Read 8 Oct 2026 · docs.percona.com

Load and replication checks

It can pause or abort when server load is too high and pause copying when it detects delayed replicas.Read 8 Oct 2026 · docs.percona.com

Requirements

The tool requires Perl, DBI, DBD::mysql, and MySQL 5.0.2 or newer, along with specified MySQL privileges.Read 8 Oct 2026 · docs.percona.com

Trigger limitation

The tool will not work on a table that already has triggers defined because it uses triggers to keep the replacement table updated.Read 8 Oct 2026 · docs.percona.com

Plans and prices

Every pt-online-schema-change plan and price →

Where Specifiction places it

• Database Migration Tools#21 of 327.5