Aggregate calc speedup (remove CheckReplaceEntry?)

[githubmanticore]

We have a CSphImplicitGroupSorter::CheckReplaceEntry which copies one match to another if their rowid is less. This looks unnecessary because we are only calculating aggregates and rowid should not matter at all. We need to try to remove that func, run the tests and evaluate the consequences.

[githubmanticore]

➤ Ilya Kuznetsov commented:

Relevant code was added in a5a1772

[githubmanticore]

➤ Sergey Nikolaev commented:

To understand the priority of this please let me know how long would it take and what kind of queries would it improve and by how much?

[githubmanticore]

➤ Ilya Kuznetsov commented:

3-4 hours. Any queries with aggregates and without grouping. By how much - no idea, depends on the data.

[githubmanticore]

➤ Ilya Kuznetsov commented:

Done in 0a82cd7