Subject Re: [firebird-support] Sudden increase in execution times
Author PenWin
Ann W. Harrison napsal(a):
> Ah. That's almost the same cost as a deletion - the old version of the
> history record has to be garbage collected. If there's an index on the
> deleted field in history, the index entry must also be removed. Since
> there are likely to be LOTS of entries in that index with the same
> the index deletion will be expensive ... less so in 2.0x than 1.5x.
I am sure that is so in the general case, but it's unlikely to apply
here - the query I am trying to solve doesn't do any deletions and there
are very few, if any, deletes on any of the two tables concerned.