Thread: BUG #16255: No respect for 'not materialized' on CTEs with group by
BUG #16255: No respect for 'not materialized' on CTEs with group by
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The following bug has been logged on the website: Bug reference: 16255 Logged by: Robert Ford Email address: robfordww@gmail.com PostgreSQL version: 12.1 Operating system: Windows Description: I have an simple CTE expression with group by and a string_aggr() function, and Postgresql seems to materialize it anyhow, even if 'not materialized' is instructed. I can't see that this is documented behaviour.
PG Bug reporting form <noreply@postgresql.org> writes: > I have an simple CTE expression with group by and a string_aggr() function, > and Postgresql seems to materialize it anyhow, even if 'not materialized' is > instructed. I can't see that this is documented behaviour. Since you haven't given a concrete example, nobody else can see whether it is either. But in general, there is no guarantee that "NOT MATERIALIZED" will do anything. There are multiple conditions that will prevent inlining a CTE, either for semantic or implementation reasons. regards, tom lane