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Adjust cost for re-creating a row from the JOIN CACHE

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Creating a record from the join cache is faster than getting a row from
the engine (less and simpler code to execute).

Added JOIN_CACHE_ROW_COPY_COST_FACTOR (0.5 for now) as the factor to
take this into account. This is multiplied with ROW_COPY_COST.

Other things:
- Added cost of copying rows to hash join, similar to join_cache joins.
This commit is contained in:
Monty
2022-06-30 15:43:58 +03:00
committed by Sergei Petrunia
parent 4515a89814
commit 07df2029a3
15 changed files with 424 additions and 414 deletions
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mysql-test/main/select_safe.test
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@ -60,6 +60,7 @@ analyze table t1;
insert into t1 values (null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a");
insert into t1 values (null,"b"),(null,"b"),(null,"c"),(null,"c"),(null,"d"),(null,"d"),(null,"e"),(null,"e"),(null,"a"),(null,"e");
insert into t1 values (null,"x"),(null,"x"),(null,"y"),(null,"y"),(null,"z"),(null,"z"),(null,"v"),(null,"v"),(null,"a"),(null,"v");
set @@optimizer_where_cost=0.3;
explain select STRAIGHT_JOIN * from t1,t1 as t2 where t1.b=t2.b;
set MAX_SEEKS_FOR_KEY=1;
explain select STRAIGHT_JOIN * from t1,t1 as t2 where t1.b=t2.b;