6
votes
Accepted
Partitioned view aggregation query not optimized
The SQL Server optimizer has two main ways to push an aggregate down past a union all.
1. Global Pushdown
The first rule is GbAggBelowUniAll. It's a fairly straightforward transform that moves the ...
- 82.1k
1
vote
PostgreSQL Query Planner overestimating Row Count leads to slow Hash Join
First, try to gather accurate statistics:
ANALYZE a;
If that doesn't help, you can choose the ugly solution of rewriting the query so that you force a nested loop join:
SELECT count(*)
FROM a
CROSS ...
- 45.5k
Only top scored, non community-wiki answers of a minimum length are eligible