Index spree_state_changes.stateful_id column #5719
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This speeds up a great deal one of the most awful queries our DB servers execute. It's not rare to see traces above 20s in Datadog 😱. In staging, with no traffic, we go from ``` EXPLAIN ANALYZE SELECT COUNT ( * ) FROM spree_state_changes WHERE spree_state_changes . stateful_id = 2024 AND spree_state_changes . stateful_type = 'Spree::Order'; Planning time: 0.142 ms Execution time: 9.073 ms ``` to ``` EXPLAIN ANALYZE SELECT COUNT ( * ) FROM spree_state_changes WHERE spree_state_changes . stateful_id = 2024 AND spree_state_changes . stateful_type = 'Spree::Order'; Planning time: 0.284 ms Execution time: 0.202 ms ```
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luisramos0
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Jul 2, 2020
It feels like this when you find one of those |
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Hi @sauloperez , Checked several orders as admin/superadmin on Moving to ready to go. |
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What? Why?
This speeds up a great deal one of the most awful queries our DB servers execute. It's not rare to see traces above 20s in Datadog 😱. Source: https://app.datadoghq.com/apm/traces?from_ts=1591104006364&index=apm-search&live=true&query=env%3Aproduction+service%3Arails-postgres+operation_name%3Apostgres.query+resource_name%3A%22SELECT+COUNT+%28+%2A+%29+FROM+spree_state_changes+WHERE+spree_state_changes+.+stateful_id+%3D+%3F+AND+spree_state_changes+.+stateful_type+%3D+%3F%22&spanID&stream_sort=desc&to_ts=1593696006364&trace&traceID
In staging, with no traffic, we go from
to
There's no point on indexing any other column because apparently there's only a
stateful_type,Spree::Order.What should we test?
There's not much we can test. As far as I know this query is only executed when accessing /admin/orders/Rxxxxx/edit. It should keep working but an index can't break it anyway.
Release notes
Speed up order edition from admin and lower the pressure it exerts on the DB.
Changelog Category: Changed