Re: WIP: Covering + unique indexes. (the good and the bad)

On 2018-04-06 20:08, Alexander Korotkov wrote:

[0001-Covering-v15.patch]

After some more testing I notice there is also a down-side/slow-down to this patch that is not so bad but more than negligible, and I don't think it has been mentioned (but I may have missed something in this thread that's now been running for 1.5 year, not to mention the tangential btree-thread(s)).

I attach my test-program, which compares master (this morning) with covered_indexes (warning: it takes a while to generate the used tables).

The test tables are created as:
  create table $t (c1 int, c2 int, c3 int, c4 int);
  insert into $t (select x, 2*x, 3*x, 4 from generate_series(1, $rowcount) as x);
  create unique index ${t}uniqueinclude_idx on $t using btree (c1, c2) include (c3, c4);

or for HEAD, just:
  create unique index ${t}unique_idx on $t using btree (c1, c2);