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Removed /2 of InnoDB ref_per_key[] estimates

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The original code was there to favor index search over table scan.
This is not needed anymore as the cost calculations for table scans
and index lookups are now more exact.
This commit is contained in:
Monty
2023-01-26 11:38:31 +02:00
parent 87507bbb4f
commit 01c82173dd
13 changed files with 64 additions and 33 deletions
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mysql-test/main/update_use_source.result
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@ -317,7 +317,7 @@ rollback;
explain update t1 set c1=0 where exists (select 'X' from t1 a where a.c2 = t1.c2) and c2 > 3;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 range t1_c2 t1_c2 5 NULL 2 Using where
2 DEPENDENT SUBQUERY a ref t1_c2 t1_c2 5 test.t1.c2 4 Using index
2 DEPENDENT SUBQUERY a ref t1_c2 t1_c2 5 test.t1.c2 8 Using index
start transaction;
update t1 set c1=c1+10 where exists (select 'X' from t1 a where a.c2 = t1.c2) and c2 >= 3;
affected rows: 4