Re: Parallel CREATE INDEX for BRIN indexes

On 16.08.24 11:22, Tomas Vondra wrote:
>> These pageinspect tests added a new use of the md5() function.  We got
>> rid of those in the tests for PG17.  You could write the test case with
>> something like
>>
>>   SELECT (CASE WHEN (mod(i,231) = 0) OR (i BETWEEN 3500 AND 4000) THEN
>> NULL ELSE i END),
>> -       (CASE WHEN (mod(i,233) = 0) OR (i BETWEEN 3750 AND 4250) THEN
>> NULL ELSE md5(i::text) END),
>> +       (CASE WHEN (mod(i,233) = 0) OR (i BETWEEN 3750 AND 4250) THEN
>> NULL ELSE encode(sha256(i::text::bytea), 'hex') END),
>>          (CASE WHEN (mod(i,233) = 0) OR (i BETWEEN 3850 AND 4500) THEN
>> NULL ELSE (i/100) + mod(i,8) END)
>>
>> But this changes the test output slightly and I'm not sure if this gives
>> you the data distribution that you need for you test.  Could your check
>> this please?
>>
> 
> I think this is fine. The output only changes because sha256 produces
> longer values than md5, so that the summaries are longer the index gets
> a page longer. AFAIK that has no impact on the test.

Ok, I have committed that.  Thanks for checking.