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Merge pull request #1076 from matrix-org/erikj/state_storage 

Use windowing function to make use of index
This commit is contained in:
Erik Johnston 2016-09-07 14:57:25 +01:00 committed by GitHub
parent 94a83b534f 513188aa56
commit 91279fd218
1 changed files with 10 additions and 5 deletions
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15
synapse/storage/state.py
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@ -315,6 +315,10 @@ class StateStore(SQLBaseStore):
# against `state_groups_state` to fetch the latest state.
# It assumes that previous state groups are always numerically
# lesser.
# The PARTITION is used to get the event_id in the greatest state
# group for the given type, state_key.
# This may return multiple rows per (type, state_key), but last_value
# should be the same.
sql = ("""
WITH RECURSIVE state(state_group) AS (
VALUES(?::bigint)
@ -322,11 +326,12 @@ class StateStore(SQLBaseStore):
SELECT prev_state_group FROM state_group_edges e, state s
WHERE s.state_group = e.state_group
)
SELECT type, state_key, event_id FROM state_groups_state
WHERE ROW(type, state_key, state_group) IN (
SELECT type, state_key, max(state_group) FROM state
INNER JOIN state_groups_state USING (state_group)
GROUP BY type, state_key
SELECT type, state_key, last_value(event_id) OVER (
PARTITION BY type, state_key ORDER BY state_group ASC
ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
) AS event_id FROM state_groups_state
WHERE state_group IN (
SELECT state_group FROM state
)
%s;
""") % (where_clause,)