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https://git.anonymousland.org/anonymousland/synapse.git
synced 2025-11-20 00:52:23 -05:00
df8a3cef6b
The query keeps showing up in my slow query log.
This changes the plan under the top-level Sort node from
```
WindowAgg (cost=280335.88..292963.15 rows=561212 width=80) (actual time=138.651..160.562 rows=27112 loops=1)
-> Sort (cost=280335.88..281738.91 rows=561212 width=84) (actual time=138.597..140.622 rows=27112 loops=1)
Sort Key: state_groups_state.type, state_groups_state.state_key, state_groups_state.state_group
Sort Method: quicksort Memory: 4581kB
-> Nested Loop (cost=2.83..226745.22 rows=561212 width=84) (actual time=21.548..47.657 rows=27112 loops=1)
-> HashAggregate (cost=2.27..3.28 rows=101 width=8) (actual time=21.526..21.535 rows=20 loops=1)
Group Key: state.state_group
-> CTE Scan on state (cost=0.00..2.02 rows=101 width=8) (actual time=21.280..21.493 rows=20 loops=1)
-> Index Scan using state_groups_state_type_idx on state_groups_state (cost=0.56..2189.40 rows=5557 width=84) (actual time=0.005..0.991 rows=1356 loops=20)
Index Cond: (state_group = state.state_group)
```
to
```
Nested Loop (cost=2.83..226745.22 rows=561212 width=84) (actual time=24.194..52.834 rows=27112 loops=1)
-> HashAggregate (cost=2.27..3.28 rows=101 width=8) (actual time=24.130..24.138 rows=20 loops=1)
Group Key: state.state_group
-> CTE Scan on state (cost=0.00..2.02 rows=101 width=8) (actual time=23.887..24.113 rows=20 loops=1)
-> Index Scan using state_groups_state_type_idx on state_groups_state (cost=0.56..2189.40 rows=5557 width=84) (actual time=0.016..1.159 rows=1356 loops=20)
Index Cond: (state_group = state.state_group)
```
This cuts the execution time from ~190ms to ~130ms, i.e. a reduction
of ~30%.
The full plans are visualised at https://explain.depesz.com/s/WpbT and
https://explain.depesz.com/s/KlEk
Signed-off-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
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| .. | ||
| _scripts | ||
| api | ||
| app | ||
| appservice | ||
| config | ||
| crypto | ||
| events | ||
| federation | ||
| groups | ||
| handlers | ||
| http | ||
| logging | ||
| metrics | ||
| module_api | ||
| push | ||
| replication | ||
| res/templates | ||
| rest | ||
| server_notices | ||
| spam_checker_api | ||
| state | ||
| static | ||
| storage | ||
| streams | ||
| util | ||
| __init__.py | ||
| event_auth.py | ||
| notifier.py | ||
| python_dependencies.py | ||
| secrets.py | ||
| server.py | ||
| server.pyi | ||
| types.py | ||
| visibility.py | ||