Re: Poor performance with row wise comparisons

2025-10-17 Thread Peter Geoghegan
On Fri, Feb 7, 2025 at 2:05 AM Jon Emord wrote: > My expectation is that the following two queries would have roughly the same > performance. > They both use the same index only scans and return the same 100 rows of data. > The main difference I see in the explain output is that the row wise > c

Re: Question about nested loops..

2025-10-17 Thread Andrei Lepikhov
On 9/10/2025 10:52, Frits Jalvingh wrote: I do not understand why the simpler query (without the self join) produces a plan that seems to require nested loops, I hope someone can explain. It seems obvious. You have a join clause: 'enheid.id_h_eenheid = huurovereenkomst_s._l_eenheid' One side o

Re: Poor performance with row wise comparisons

2025-10-17 Thread David G. Johnston
On Friday, October 10, 2025, wrote: > Looking for help on storing and retrieving the personal data as masked. > Any references and implementation details would help > Don’t reply to existing threads with unrelated stuff. Just send an email to begin your own thread. And choose an appropriate pl

Re: Indexes on expressions with multiple columns and operators

2025-10-17 Thread Frédéric Yhuel
On 9/23/25 12:43, Andrei Lepikhov wrote: But is it the same for the 'distinct' statistics? It seems you should love it - the number of groups in GROUP-BY, DISTINCT, and even HashJoin should be estimated more precisely, no? I think it has more potential, and I would love to use this weapon,

Re: Indexes on expressions with multiple columns and operators

2025-10-17 Thread Andrei Lepikhov
On 23/9/2025 15:31, Frédéric Yhuel wrote: To get back to the topic of partitioned statistics, do you know if SQL Server is smart enough to handle this case [1] that we discussed last year? (with filtered statistics) [1] https://www.postgresql.org/message-id/flat/b860c71a-7cab-4d88- ad87-8c1f2

Re: Indexes on expressions with multiple columns and operators

2025-10-17 Thread Andrei Lepikhov
On 13/10/2025 16:55, Tom Lane wrote: Andrei Lepikhov writes: On 25/9/2025 12:41, Frédéric Yhuel wrote: So, on SQL Server, you can do this: CREATE STATISTICS FooStats ON foo (ackid, crit) WHERE crit = 'WARNING'; Nice! Thanks for the report. I think the only reason why Postgres doesn't have i