50 lines
2.1 KiB
Text
50 lines
2.1 KiB
Text
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[[_migrate_db]]
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== Database migration
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{project_name} can automatically migrate the database schema, or you can choose to do it manually. By default the
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database is automatically migrated when you start the new installation for the first time.
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=== Automatic relational database migration
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To enable automatic upgrading of the database schema, set the migration-strategy property value to "update" for the
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default connections-jpa provider:
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[source,bash]
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----
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kc.[sh|bat] start --spi-connections-jpa-default-migration-strategy=update
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----
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When you start the server with this setting your database is automatically migrated if the database schema has changed
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in the new version.
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Creating an index on huge tables with millions of records can easily take a huge amount of time
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and potentially cause major service disruption on upgrades.
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For those cases, we added a threshold (the number of records) for automated index creation.
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By default, this threshold is `300000` records.
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When the number of records is higher than the threshold, the index is not created automatically,
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and there will be a warning message in server logs including SQL commands which can be applied later manually.
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To change the threshold, set the `index-creation-threshold` property, value for the default `connections-liquibase` provider:
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[source,bash]
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----
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kc.[sh|bat] start --spi-connections-liquibase-default-index-creation-threshold=300000
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----
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=== Manual relational database migration
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To enable manual upgrading of the database schema, set the migration-strategy property value to "manual" for the default
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connections-jpa provider:
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[source,bash]
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----
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kc.[sh|bat] start --spi-connections-jpa-default-migration-strategy=manual
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----
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When you start the server with this configuration it checks if the database needs to be migrated. The required changes
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are written to an SQL file that you can review and manually run against the database. For further details on how to
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apply this file to the database, see the documentation for the relational database you're using. After the changes have
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been written to the file, the server exits.
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