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
anythingobvious 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!
Frank
