perf: replace CAT_OPTIONS correlated subselect with LATERAL JOIN in DXF2 EventQuery#23743
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jason-p-pickering wants to merge 2 commits into
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perf: replace CAT_OPTIONS correlated subselect with LATERAL JOIN in DXF2 EventQuery#23743jason-p-pickering wants to merge 2 commits into
jason-p-pickering wants to merge 2 commits into
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…XF2 EventQuery Correlated subselects in the SELECT list execute once per row. Moving to a LATERAL JOIN lets the planner hoist and materialise the aggregation once per COC rather than re-evaluating it for every event row. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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Correlated sub+selects in the SELECT list execute once per row. Moving to a LATERAL JOIN lets the planner hoist and materialise the aggregation once per COC rather than re-evaluating it for every event row. The vast majority of programs do not use an AOC, so most of the time, this is always going to be "default". The subselect was doing redundant work proportional to event count even when the answer was identical every time. LATERAL collapses that.
Testing on a production scale system reveals that the query time can be decreased from 220ms to under 70ms.
Tracker performance tests were inconclusive, but there appeared to be no regression. The difference on the production scale DB was relatively modest, even with millions of events.
Median Response Time (p50) (ms)
95th Percentile Response Time (p95) (ms)
⬇️ = faster (improvement), ⬆️ = slower (regression)