Hi Sergei,

commit d2b4782200ccfd0850f36d25c75082974e4b86e1 Author: Sergei Krivonos <sergei.krivonos@mariadb.com> Date: Sun Nov 14 10:37:20 2021 +0200

MDEV-27036: duplicated keys in best_access_path

diff --git a/sql/sql_select.cc b/sql/sql_select.cc index 3272f8b7f65..29e9c0efe36 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -7611,16 +7611,14 @@ best_access_path(JOIN *join, } else { + trace_access_idx.add("used_range_estimates", false); if (table->quick_keys.is_set(key)) { - trace_access_idx.add("used_range_estimates",false) - .add("cause", - "not better than ref estimates"); + cause= "not better than ref estimates";

Issue #1: you make this change here, in the branch marked as ReuseRangeEstimateForRef-2. But there's very similar code right above, in ReuseRangeEstimateForRef-1 branch: /* quick_range couldn't use key! */ records= (double) s->records/rec; trace_access_idx.add("used_range_estimates", false) .add("cause", "not available"); Issue #2: this patch causes some information to be removed from the trace! How about an alternative solution: change the name from "cause" here to "reason"?

} else { - trace_access_idx.add("used_range_estimates", false) - .add("cause", "not available"); + cause= "not available"; } } }

BR Sergei -- Sergei Petrunia, Software Developer MariaDB Corporation | Skype: sergefp | Blog: http://petrunia.net