pá 19. 3. 2021 v 9:53 odesílatel Frank Millman <frank@chagford.com> napsal:
On 2021-03-19 10:29 AM, Thomas Kellerer wrote: > Frank Millman schrieb am 19.03.2021 um 09:19: >> This may be a non-issue, and I don't want to waste your time. But perhaps someone can have a look to see if there is anything obvious I have missed. >> >> I am writing a cross-platform accounting app, and I test using Sql >> Server on Windows 10 and PostgreSql on Fedora 31. Performance is >> usually very similar, with a slight edge to PostgreSql. Now I have a >> SELECT which runs over twice as fast on Sql Server compared to >> PostgreSql. >> > Can you change the SELECT statement? > > Very often "distinct on ()" is faster in Postgres compared to the equivalent solution using window functions > > Something along the lines (for the first derived table): > > SELECT ... > FROM ( > SELECT a.source_code_id, SUM(a.tran_tot) AS cl_tot > FROM ( > SELECT distinct on (location_row_id, function_row_id, source_code_id) source_code_id, tran_tot > FROM prop.ar_totals > WHERE deleted_id = 0 > AND tran_date <= '2018-03-31' > AND ledger_row_id = 1 > ORDER BY location_row_id, function_row_id, source_code_id, tran_date DESC > ) AS a > GROUP BY a.source_code_id > ) as cl_bal > ... Thanks, Thomas
I tried that, and it ran about 10% faster. Every little helps, but SQL Server appears to have some secret sauce!
