06.01.2022 17:13, Adriano dos Santos Fernandes wrote:
See also:
https://github.com/FirebirdSQL/firebird/issues/1355
https://github.com/FirebirdSQL/firebird/commit/626ab18c426fd32d482e02093e72e57330596174
Worth testing GROUP BY <literal>, <field> ?
Since v3 we must be safe. Aggregate stream allocates impure space for
the expressions in its own region.
Correct, although I find it weird that the impure space is allocated
dynamically rather than statically (in the request's impure area):
unsigned impureCount = m_group ? m_group->getCount() : 0;
if (!impure->groupValues && impureCount > 0)
{
impure->groupValues = FB_NEW_POOL(*tdbb->getDefaultPool())
impure_value[impureCount];
memset(impure->groupValues, 0, sizeof(impure_value) * impureCount);
}
Why is it done this way? AFAIU, impureCount is known during the compile
time, so the whole impure area could be preallocated during the prepare
stage.
I'd say the flag exists because things were different before. Aggregate
were using expressions' impure regions.
Then FLAG_VALUE may be safely removed.
Dmitry
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