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To support changing the internals of an aggregate root without having to throw away the old snapshots the snapshot version can now be specified. This is needed to be able to support zero-downtime deployments, where both old and new code run concurrently using the same event store, but each may require different snapshots. Example usage: ``` enable_snapshots version: 2 ``` The default version is 1.
Pass snapshot version information when retrieving and storing snapshots from/to the database. A hash of aggregate types to supported snapshot version is passed on every call that needs it so the snapshot can be correctly selected. The default implementation queries all descendants of AggregateRoot for the supported snapshot version. This can be configured with the `aggregate_snapshot_versions` setting.
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When the snapshot format changes for an aggregate that needs snapshots, a new row is inserted into the `aggregates_that_need_snapshots` table with the updated version number. This will cause the snapshotter to select this aggregate to create a new snapshot with the new version.
This task should be executed when the new code is fully deployed to all machines, and the other snapshot versions are no longer required.
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To support changing the internals of an aggregate root without having
to throw away the old snapshots the snapshot version can now be
specified. This is needed to be able to support zero-downtime
deployments, where both old and new code run concurrently using the
same event store, but each may require different snapshots.
Example usage:
The default version is 1.
A hash mapping aggregate types to the supported snapshot version is
passed to every database call that needs it so the snapshot can be
correctly selected. The default implementation queries all descendants
of
AggregateRootfor the supported snapshot version. This can bechanged using the
aggregate_snapshot_versionsconfiguration setting.