PostgreSQL in Bitrix

Baseline: main 23.0+. Supported in Enterprise for PostgreSQL licenses (B24 and CMS). Connection class: \Bitrix\Main\DB\PgsqlConnection.

Configuration

'connections' => [
    'value' => [
        'default' => [
            'className' => \Bitrix\Main\DB\PgsqlConnection::class,
            'host' => 'localhost',
            'database' => 'bx',
            'login' => 'bx',
            'password' => '***',
            'options' => \Bitrix\Main\DB\Connection::DEFERRED,
        ],
    ],
    'readonly' => true,
],

Before Migration

1. Check that the current license stays valid through the whole test period (up to 6 months) and the final switch — renew it first if it expires earlier.
2. Obtain Enterprise for PostgreSQL license. It provides a coupon (activate it only after migration testing) and a test key for a separate test install; testing window is max 6 months from purchase. During testing the production site keeps running on MySQL under the current license — the test key is for the test environment only.
3. Update Performance Monitor module to 24.0.0+.
4. Project must use UTF-8 encoding.
5. Close site to visitors during migration.
6. Test on staging first — return to MySQL after production PostgreSQL launch requires manual work.

Module Compatibility

Not all kernel and marketplace modules support PostgreSQL. Incompatible modules are disabled during conversion wizard.

Check custom code:

• MySQL-specific SQL (LIMIT syntax differences handled by SqlHelper, but raw SQL may break).
• MySQL install scripts under install/mysql/ or install/db/mysql/ need matching PostgreSQL scripts under install/pgsql/ or install/db/pgsql/.

Find modules missing pgsql install:

for mysql in bitrix/modules/*/install/mysql/install.sql bitrix/modules/*/install/db/mysql/install.sql; do
  pgsql=$(echo $mysql | sed 's#/mysql/#/pgsql/#')
  test -e $pgsql || echo "missing: $pgsql"
done

Check kernel module install folders: each supporting module should have matching install/pgsql/ or install/db/pgsql/ scripts. Inspect bitrix/modules/<module>/install/ in the project.

Migration Methods

1. Wizard — Admin conversion tool (lists disabled modules on step 1).
2. CLI — manual server-side migration via Performance Monitor module tools.

Writing Compatible Code

• Use ORM and SqlHelper — avoid MySQL-specific functions in raw SQL.
• Use SqlExpression placeholders instead of string concatenation.
• Test DDL in both MySQL (install/mysql/ or install/db/mysql/) and PostgreSQL (install/pgsql/ or install/db/pgsql/) if the module supports both.
• Avoid ENGINE=InnoDB, backticks-specific syntax, UNSIGNED.

Checklist

• License is Enterprise for PostgreSQL.
• All custom modules checked for pgsql install scripts.
• Raw SQL audited for MySQL-specific syntax.
• Migration tested on copy before production.
• Marketplace modules verified with vendors.