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MDEV-30699: Updated prev_record_reads() to be more exact

Browse source 
The old code in prev_record_reads() did give wrong estimates when a
join_buffer was used or if the table was depending on more than one
other tables. When join_cache is used, it will cause a re-order of row
combinations, which causes more calls to the engine for tables that
are depending on tables before the join_cached one.

The new prev_records_read() code provides more exact estimates and
should never give a 'too low estimate', assuming that the data to the
function is correct

The definition of prev_record_read() is also updated.
The new definition is:
  "Estimate the number of engine ha_index_read_calls for EQ_REF tables
  when taking into account the one-row-cache in join_read_always_key()"

The cost of using prev_record_reads() value is changed. The value is
now used similar as before to calculate the cost of the storage engine
calls. However the cost of the WHERE cost is changed to take into
account the total number of row combinations as the WHERE has to be
checked even if the one-row-cache is used. This makes the cost
slightly higher than before (for the same prev_record_reads() value).

Other things:
- Cached return value of prev_record_read() in best_access_path() to
  avoid some function calls.
- Fixed bug where position[].use_join_buffer was set in
  best_acess_path() when join buffer was not used. This confused the
  semi join optimizer to try to reoptimize plans that did not need to be
  reoptimized.
  The effect of the bug fix is that we avoid doing some re-optimziations
  with semi-joins when join_buffer is not used. In these cases the value
  shown for the 'Filtering' column in EXPLAIN EXTENDED may change.
- Added 'prev_record.cc' that was used to verify the logic in
  prev_record_reads().

Changes in test suite:
- EQ_REF tables are moved up to be earlier. This is because either the
  higher WHERE cost when EQ_REF is used with more row combination or
  change of cost when using join_cache.
- Filtered has changed (to the better) for some cases using semi-joins
  subselect_sj.test subselect_sj_jcl6.test
This commit is contained in:
Monty 2023-02-14 15:20:14 +02:00 committed by Sergei Petrunia
parent 793caf3a27
commit 15e889c300
15 changed files with 893 additions and 234 deletions
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135
mysql-test/main/greedy_optimizer.result
View file

@ -127,7 +127,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 1.650935
Last_query_cost 4.284314
explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3
@ -139,7 +139,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 1.650935
Last_query_cost 4.284314
explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
@ -198,76 +198,76 @@ select @@optimizer_search_depth;
0
explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 1.405838
Last_query_cost 2.998640
explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 1.405838
Last_query_cost 2.998640
explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using join buffer (flat, BNL join)
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using join buffer (flat, BNL join)
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.c21 1 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 0.494824
Last_query_cost 0.602062
explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using join buffer (flat, BNL join)
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using join buffer (flat, BNL join)
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.c21 1 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 0.494824
Last_query_cost 0.602062
explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.c21 1 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 0.453844
Last_query_cost 0.621783
explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.c21 1 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 0.453844
Last_query_cost 0.621783
set optimizer_search_depth=1;
select @@optimizer_search_depth;
@@optimizer_search_depth
@ -283,7 +283,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 34.291074
Last_query_cost 42.599713
explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t7 index PRIMARY PRIMARY 4 NULL 21 Using index
@ -295,7 +295,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 34.291074
Last_query_cost 42.599713
explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 index PRIMARY PRIMARY 4 NULL 9 Using index
@ -307,7 +307,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 14.789792
Last_query_cost 14.817907
explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 index PRIMARY PRIMARY 4 NULL 9 Using index
@ -319,7 +319,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 14.789792
Last_query_cost 14.817907
explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL PRIMARY NULL NULL NULL 3 Using where
@ -350,76 +350,76 @@ select @@optimizer_search_depth;
62
explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 1.405838
Last_query_cost 2.998640
explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 1.405838
Last_query_cost 2.998640
explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using join buffer (flat, BNL join)
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using join buffer (flat, BNL join)
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.c21 1 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 0.494824
Last_query_cost 0.602062
explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using join buffer (flat, BNL join)
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using join buffer (flat, BNL join)
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.c21 1 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 0.494824
Last_query_cost 0.602062
explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.c21 1 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 0.453844
Last_query_cost 0.621783
explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.c21 1 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 0.453844
Last_query_cost 0.621783
set optimizer_prune_level=2;
select @@optimizer_prune_level;
@@optimizer_prune_level
@ -439,7 +439,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 1.650935
Last_query_cost 4.284314
explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3
@ -451,7 +451,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 1.650935
Last_query_cost 4.284314
explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
@ -515,7 +515,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 34.291074
Last_query_cost 42.599713
explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t7 index PRIMARY PRIMARY 4 NULL 21 Using index
@ -527,7 +527,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 34.291074
Last_query_cost 42.599713
explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 index PRIMARY PRIMARY 4 NULL 9 Using index
@ -539,7 +539,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 14.789792
Last_query_cost 14.817907
explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 index PRIMARY PRIMARY 4 NULL 9 Using index
@ -551,7 +551,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where; Using join buffer (flat, BNL join)
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 14.789792
Last_query_cost 14.817907
explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL PRIMARY NULL NULL NULL 3 Using where
@ -591,7 +591,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 1.650935
Last_query_cost 4.284314
explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3
@ -603,7 +603,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 1.650935
Last_query_cost 4.284314
explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
@ -1194,14 +1194,17 @@ AND t10000.I=t10.I;
COUNT(*)
9000
### NOTE: Handler_reads: 9030, expected: 9045 ###
#####
## EQ_REF & REF join two instances of t10000 with t10:
#####
flush status;
EXPLAIN SELECT STRAIGHT_JOIN COUNT(*) FROM t10000 y, t10, t10000 x
EXPLAIN SELECT STRAIGHT_JOIN COUNT(*) FROM t10,t10000 x,t10000 y
WHERE x.k=t10.i;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE y index NULL PRIMARY 4 NULL 10000 Using index
1 SIMPLE t10 range IX IX 5 NULL 10 Using where; Using index; Using join buffer (flat, BNL join)
1 SIMPLE t10 index IX IX 5 NULL 10 Using where; Using index
1 SIMPLE x eq_ref PRIMARY PRIMARY 4 test.t10.I 1 Using index
SELECT STRAIGHT_JOIN COUNT(*) FROM t10000 y, t10, t10000 x
1 SIMPLE y index NULL PRIMARY 4 NULL 10000 Using index; Using join buffer (flat, BNL join)
SELECT STRAIGHT_JOIN COUNT(*) FROM t10,t10000 x,t10000 y
WHERE x.k=t10.i;
COUNT(*)
90000
@ -1209,9 +1212,9 @@ flush status;
EXPLAIN SELECT COUNT(*) FROM t10,t10000 x,t10000 y
WHERE x.k=t10.i;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE y index NULL PRIMARY 4 NULL 10000 Using index
1 SIMPLE t10 range IX IX 5 NULL 10 Using where; Using index; Using join buffer (flat, BNL join)
1 SIMPLE t10 index IX IX 5 NULL 10 Using where; Using index
1 SIMPLE x eq_ref PRIMARY PRIMARY 4 test.t10.I 1 Using index
1 SIMPLE y index NULL PRIMARY 4 NULL 10000 Using index; Using join buffer (flat, BNL join)
SELECT COUNT(*) FROM t10,t10000 x,t10000 y
WHERE x.k=t10.i;
COUNT(*)
@ -1220,9 +1223,9 @@ flush status;
EXPLAIN SELECT COUNT(*) FROM t10,t10000 y,t10000 x
WHERE x.k=t10.i;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE y index NULL PRIMARY 4 NULL 10000 Using index
1 SIMPLE t10 range IX IX 5 NULL 10 Using where; Using index; Using join buffer (flat, BNL join)
1 SIMPLE t10 index IX IX 5 NULL 10 Using where; Using index
1 SIMPLE x eq_ref PRIMARY PRIMARY 4 test.t10.I 1 Using index
1 SIMPLE y index NULL PRIMARY 4 NULL 10000 Using index; Using join buffer (flat, BNL join)
SELECT COUNT(*) FROM t10,t10000 y,t10000 x
WHERE x.k=t10.i;
COUNT(*)

8
mysql-test/main/greedy_optimizer.test
View file

@ -654,15 +654,15 @@ WHERE t100.K=t10.I
--source include/check_qep.inc
#####
## EQ_REF & REF join two instances of t10000 with t10:
#####
--echo #####
--echo ## EQ_REF & REF join two instances of t10000 with t10:
--echo #####
#####
## Expect this QEP, cost & #handler_read
# Expected QEP: 'join EQ_REF(X) on X.K=t10.I' before 'cross' ALL(Y)
let $query=
SELECT STRAIGHT_JOIN COUNT(*) FROM t10000 y, t10, t10000 x
SELECT STRAIGHT_JOIN COUNT(*) FROM t10,t10000 x,t10000 y
WHERE x.k=t10.i;
--source include/expect_qep.inc

32
mysql-test/main/join_cache.result
View file

@ -4398,9 +4398,9 @@ SELECT t2.v FROM t1, t2, t3
WHERE t3.v <> t2.v AND t3.pk = t2.i AND t1.v = t3.v AND t1.pk*2<100
GROUP BY t2.v ORDER BY t1.pk,t2.v;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL idx2 NULL NULL NULL 44 Using where; Using temporary; Using filesort
1 SIMPLE t2 index idx1 idx2 7 NULL 20 Using where; Using index; Using join buffer (flat, BNL join)
1 SIMPLE t2 index idx1 idx2 7 NULL 20 Using index; Using temporary; Using filesort
1 SIMPLE t3 eq_ref PRIMARY,idx2 PRIMARY 4 test.t2.i 1 Using where
1 SIMPLE t1 ref idx2 idx2 3 test.t3.v 5 Using where
SELECT t2.v FROM t1, t2, t3
WHERE t3.v <> t2.v AND t3.pk = t2.i AND t1.v = t3.v AND t1.pk*2<100
GROUP BY t2.v ORDER BY t1.pk,t2.v;
@ -4415,9 +4415,9 @@ SELECT t2.v FROM t1, t2, t3
WHERE t2.v <> t3.v AND t3.pk = t2.i AND t1.v = t3.v AND t1.pk*2<100
GROUP BY t2.v ORDER BY t1.pk,t2.v;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL idx2 NULL NULL NULL 44 Using where; Using temporary; Using filesort
1 SIMPLE t2 index idx1 idx2 7 NULL 20 Using where; Using index; Using join buffer (flat, BNL join)
1 SIMPLE t2 index idx1 idx2 7 NULL 20 Using index; Using temporary; Using filesort
1 SIMPLE t3 eq_ref PRIMARY,idx2 PRIMARY 4 test.t2.i 1 Using where
1 SIMPLE t1 ref idx2 idx2 3 test.t3.v 5 Using where
SELECT t2.v FROM t1, t2, t3
WHERE t2.v <> t3.v AND t3.pk = t2.i AND t1.v = t3.v AND t1.pk*2<100
GROUP BY t2.v ORDER BY t1.pk,t2.v;
@ -4433,9 +4433,9 @@ SELECT t2.v FROM t1, t2, t3
WHERE t3.v <> t2.v AND t3.pk = t2.i AND t1.v = t3.v AND t1.pk*2<100
GROUP BY t2.v ORDER BY t1.pk,t2.v;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL idx2 NULL NULL NULL 44 Using where; Using temporary; Using filesort
1 SIMPLE t2 index idx1 idx2 7 NULL 20 Using where; Using index; Using join buffer (flat, BNL join)
1 SIMPLE t3 eq_ref PRIMARY,idx2 PRIMARY 4 test.t2.i 1 Using where; Using join buffer (incremental, BKA join); Key-ordered Rowid-ordered scan
1 SIMPLE t2 index idx1 idx2 7 NULL 20 Using index; Using temporary; Using filesort
1 SIMPLE t3 eq_ref PRIMARY,idx2 PRIMARY 4 test.t2.i 1 Using where; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
1 SIMPLE t1 ref idx2 idx2 3 test.t3.v 5 Using where; Using join buffer (incremental, BKA join); Key-ordered Rowid-ordered scan
SELECT t2.v FROM t1, t2, t3
WHERE t3.v <> t2.v AND t3.pk = t2.i AND t1.v = t3.v AND t1.pk*2<100
GROUP BY t2.v ORDER BY t1.pk,t2.v;
@ -4450,9 +4450,9 @@ SELECT t2.v FROM t1, t2, t3
WHERE t2.v <> t3.v AND t3.pk = t2.i AND t1.v = t3.v AND t1.pk*2<100
GROUP BY t2.v ORDER BY t1.pk,t2.v;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL idx2 NULL NULL NULL 44 Using where; Using temporary; Using filesort
1 SIMPLE t2 index idx1 idx2 7 NULL 20 Using where; Using index; Using join buffer (flat, BNL join)
1 SIMPLE t3 eq_ref PRIMARY,idx2 PRIMARY 4 test.t2.i 1 Using where; Using join buffer (incremental, BKA join); Key-ordered Rowid-ordered scan
1 SIMPLE t2 index idx1 idx2 7 NULL 20 Using index; Using temporary; Using filesort
1 SIMPLE t3 eq_ref PRIMARY,idx2 PRIMARY 4 test.t2.i 1 Using where; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
1 SIMPLE t1 ref idx2 idx2 3 test.t3.v 5 Using where; Using join buffer (incremental, BKA join); Key-ordered Rowid-ordered scan
SELECT t2.v FROM t1, t2, t3
WHERE t2.v <> t3.v AND t3.pk = t2.i AND t1.v = t3.v AND t1.pk*2<100
GROUP BY t2.v ORDER BY t1.pk,t2.v;
@ -4468,9 +4468,9 @@ SELECT t2.v FROM t1, t2, t3
WHERE t3.v <> t2.v AND t3.pk = t2.i AND t1.v = t3.v AND t1.pk*2<100
GROUP BY t2.v ORDER BY t1.pk,t2.v;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL idx2 NULL NULL NULL 44 Using where; Using temporary; Using filesort
1 SIMPLE t2 index idx1 idx2 7 NULL 20 Using where; Using index; Using join buffer (flat, BNL join)
1 SIMPLE t3 hash_ALL PRIMARY,idx2 #hash#PRIMARY 4 test.t2.i 20 Using where; Using join buffer (incremental, BNLH join)
1 SIMPLE t2 index idx1 idx2 7 NULL 20 Using index; Using temporary; Using filesort
1 SIMPLE t3 hash_ALL PRIMARY,idx2 #hash#PRIMARY 4 test.t2.i 20 Using where; Using join buffer (flat, BNLH join)
1 SIMPLE t1 hash_ALL idx2 #hash#idx2 3 test.t3.v 44 Using where; Using join buffer (incremental, BNLH join)
SELECT t2.v FROM t1, t2, t3
WHERE t3.v <> t2.v AND t3.pk = t2.i AND t1.v = t3.v AND t1.pk*2<100
GROUP BY t2.v ORDER BY t1.pk,t2.v;
@ -4485,9 +4485,9 @@ SELECT t2.v FROM t1, t2, t3
WHERE t2.v <> t3.v AND t3.pk = t2.i AND t1.v = t3.v AND t1.pk*2<100
GROUP BY t2.v ORDER BY t1.pk,t2.v;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL idx2 NULL NULL NULL 44 Using where; Using temporary; Using filesort
1 SIMPLE t2 index idx1 idx2 7 NULL 20 Using where; Using index; Using join buffer (flat, BNL join)
1 SIMPLE t3 hash_ALL PRIMARY,idx2 #hash#PRIMARY 4 test.t2.i 20 Using where; Using join buffer (incremental, BNLH join)
1 SIMPLE t2 index idx1 idx2 7 NULL 20 Using index; Using temporary; Using filesort
1 SIMPLE t3 hash_ALL PRIMARY,idx2 #hash#PRIMARY 4 test.t2.i 20 Using where; Using join buffer (flat, BNLH join)
1 SIMPLE t1 hash_ALL idx2 #hash#idx2 3 test.t3.v 44 Using where; Using join buffer (incremental, BNLH join)
SELECT t2.v FROM t1, t2, t3
WHERE t2.v <> t3.v AND t3.pk = t2.i AND t1.v = t3.v AND t1.pk*2<100
GROUP BY t2.v ORDER BY t1.pk,t2.v;

6
mysql-test/main/opt_trace.result
View file

@ -11181,9 +11181,9 @@ insert into t3 values (1),(2),(3),(4),(5),(6),(7),(8),(9),(10);
explain
select * from t3 where (a,a) in (select t1.a, t2.a from t1, t2 where t1.b=t2.b);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t3 ALL NULL NULL NULL NULL 10 Using where
1 PRIMARY t1 ALL PRIMARY NULL NULL NULL 5 Using where; Using join buffer (flat, BNL join)
1 PRIMARY t2 eq_ref PRIMARY PRIMARY 4 test.t3.a 1 Using where
1 PRIMARY t1 ALL PRIMARY NULL NULL NULL 5
1 PRIMARY t2 eq_ref PRIMARY PRIMARY 4 test.t1.a 1 Using where
1 PRIMARY t3 ALL NULL NULL NULL NULL 10 Using where; Using join buffer (flat, BNL join)
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.semijoin_table_pullout')) from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
JSON_DETAILED(JSON_EXTRACT(trace, '$**.semijoin_table_pullout'))
[

2
mysql-test/main/show_explain.result
View file

@ -730,8 +730,8 @@ SELECT * FROM t2 WHERE (5, 78) IN (SELECT `a1`, MAX(`a1`) FROM t2 GROUP BY `a1`)
connection default;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 ALL NULL NULL NULL NULL 20
1 PRIMARY <subquery2> const distinct_key distinct_key 8 const,const 1
1 PRIMARY t2 ALL NULL NULL NULL NULL 20 Using join buffer (flat, BNL join)
2 MATERIALIZED t2 index NULL a1 4 NULL 20 Using index
Warnings:
Note 1003 SELECT * FROM t2 WHERE (5, 78) IN (SELECT `a1`, MAX(`a1`) FROM t2 GROUP BY `a1`)

18
mysql-test/main/stat_tables.result
View file

@ -251,11 +251,11 @@ and p_name like '%green%') as profit
group by nation, o_year
order by nation, o_year desc;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE part ALL PRIMARY NULL NULL NULL 200 Using where; Using temporary; Using filesort
1 SIMPLE partsupp ref PRIMARY,i_ps_partkey,i_ps_suppkey i_ps_partkey 4 dbt3_s001.part.p_partkey 3
1 SIMPLE supplier ALL PRIMARY,i_s_nationkey NULL NULL NULL 10 Using where; Using join buffer (flat, BNL join)
1 SIMPLE supplier ALL PRIMARY,i_s_nationkey NULL NULL NULL 10 Using where; Using temporary; Using filesort
1 SIMPLE nation eq_ref PRIMARY PRIMARY 4 dbt3_s001.supplier.s_nationkey 1
1 SIMPLE lineitem ref PRIMARY,i_l_suppkey_partkey,i_l_partkey,i_l_suppkey,i_l_orderkey,i_l_orderkey_quantity i_l_suppkey_partkey 10 dbt3_s001.part.p_partkey,dbt3_s001.partsupp.ps_suppkey 8
1 SIMPLE partsupp ref PRIMARY,i_ps_partkey,i_ps_suppkey i_ps_suppkey 4 dbt3_s001.supplier.s_suppkey 70
1 SIMPLE part eq_ref PRIMARY PRIMARY 4 dbt3_s001.partsupp.ps_partkey 1 Using where
1 SIMPLE lineitem ref PRIMARY,i_l_suppkey_partkey,i_l_partkey,i_l_suppkey,i_l_orderkey,i_l_orderkey_quantity i_l_suppkey_partkey 10 dbt3_s001.partsupp.ps_partkey,dbt3_s001.supplier.s_suppkey 8
1 SIMPLE orders eq_ref PRIMARY PRIMARY 4 dbt3_s001.lineitem.l_orderkey 1
EXPLAIN EXTENDED select nation, o_year, sum(amount) as sum_profit
from (select n_name as nation,
@ -269,14 +269,14 @@ and p_name like '%green%') as profit
group by nation, o_year
order by nation, o_year desc;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE part ALL PRIMARY NULL NULL NULL 200 100.00 Using where; Using temporary; Using filesort
1 SIMPLE partsupp ref PRIMARY,i_ps_partkey,i_ps_suppkey i_ps_partkey 4 dbt3_s001.part.p_partkey 3 100.00
1 SIMPLE supplier ALL PRIMARY,i_s_nationkey NULL NULL NULL 10 10.00 Using where; Using join buffer (flat, BNL join)
1 SIMPLE supplier ALL PRIMARY,i_s_nationkey NULL NULL NULL 10 100.00 Using where; Using temporary; Using filesort
1 SIMPLE nation eq_ref PRIMARY PRIMARY 4 dbt3_s001.supplier.s_nationkey 1 100.00
1 SIMPLE lineitem ref PRIMARY,i_l_suppkey_partkey,i_l_partkey,i_l_suppkey,i_l_orderkey,i_l_orderkey_quantity i_l_suppkey_partkey 10 dbt3_s001.part.p_partkey,dbt3_s001.partsupp.ps_suppkey 8 100.00
1 SIMPLE partsupp ref PRIMARY,i_ps_partkey,i_ps_suppkey i_ps_suppkey 4 dbt3_s001.supplier.s_suppkey 70 100.00
1 SIMPLE part eq_ref PRIMARY PRIMARY 4 dbt3_s001.partsupp.ps_partkey 1 100.00 Using where
1 SIMPLE lineitem ref PRIMARY,i_l_suppkey_partkey,i_l_partkey,i_l_suppkey,i_l_orderkey,i_l_orderkey_quantity i_l_suppkey_partkey 10 dbt3_s001.partsupp.ps_partkey,dbt3_s001.supplier.s_suppkey 8 100.00
1 SIMPLE orders eq_ref PRIMARY PRIMARY 4 dbt3_s001.lineitem.l_orderkey 1 100.00
Warnings:
Note 1003 select `dbt3_s001`.`nation`.`n_name` AS `nation`,extract(year from `dbt3_s001`.`orders`.`o_orderDATE`) AS `o_year`,sum(`dbt3_s001`.`lineitem`.`l_extendedprice` * (1 - `dbt3_s001`.`lineitem`.`l_discount`) - `dbt3_s001`.`partsupp`.`ps_supplycost` * `dbt3_s001`.`lineitem`.`l_quantity`) AS `sum_profit` from `dbt3_s001`.`part` join `dbt3_s001`.`supplier` join `dbt3_s001`.`lineitem` join `dbt3_s001`.`partsupp` join `dbt3_s001`.`orders` join `dbt3_s001`.`nation` where `dbt3_s001`.`supplier`.`s_suppkey` = `dbt3_s001`.`partsupp`.`ps_suppkey` and `dbt3_s001`.`lineitem`.`l_suppkey` = `dbt3_s001`.`partsupp`.`ps_suppkey` and `dbt3_s001`.`partsupp`.`ps_partkey` = `dbt3_s001`.`part`.`p_partkey` and `dbt3_s001`.`lineitem`.`l_partkey` = `dbt3_s001`.`part`.`p_partkey` and `dbt3_s001`.`orders`.`o_orderkey` = `dbt3_s001`.`lineitem`.`l_orderkey` and `dbt3_s001`.`nation`.`n_nationkey` = `dbt3_s001`.`supplier`.`s_nationkey` and `dbt3_s001`.`part`.`p_name` like '%green%' group by `dbt3_s001`.`nation`.`n_name`,extract(year from `dbt3_s001`.`orders`.`o_orderDATE`) desc order by `dbt3_s001`.`nation`.`n_name`,extract(year from `dbt3_s001`.`orders`.`o_orderDATE`) desc
Note 1003 select `dbt3_s001`.`nation`.`n_name` AS `nation`,extract(year from `dbt3_s001`.`orders`.`o_orderDATE`) AS `o_year`,sum(`dbt3_s001`.`lineitem`.`l_extendedprice` * (1 - `dbt3_s001`.`lineitem`.`l_discount`) - `dbt3_s001`.`partsupp`.`ps_supplycost` * `dbt3_s001`.`lineitem`.`l_quantity`) AS `sum_profit` from `dbt3_s001`.`part` join `dbt3_s001`.`supplier` join `dbt3_s001`.`lineitem` join `dbt3_s001`.`partsupp` join `dbt3_s001`.`orders` join `dbt3_s001`.`nation` where `dbt3_s001`.`partsupp`.`ps_suppkey` = `dbt3_s001`.`supplier`.`s_suppkey` and `dbt3_s001`.`lineitem`.`l_suppkey` = `dbt3_s001`.`supplier`.`s_suppkey` and `dbt3_s001`.`part`.`p_partkey` = `dbt3_s001`.`partsupp`.`ps_partkey` and `dbt3_s001`.`lineitem`.`l_partkey` = `dbt3_s001`.`partsupp`.`ps_partkey` and `dbt3_s001`.`orders`.`o_orderkey` = `dbt3_s001`.`lineitem`.`l_orderkey` and `dbt3_s001`.`nation`.`n_nationkey` = `dbt3_s001`.`supplier`.`s_nationkey` and `dbt3_s001`.`part`.`p_name` like '%green%' group by `dbt3_s001`.`nation`.`n_name`,extract(year from `dbt3_s001`.`orders`.`o_orderDATE`) desc order by `dbt3_s001`.`nation`.`n_name`,extract(year from `dbt3_s001`.`orders`.`o_orderDATE`) desc
select nation, o_year, sum(amount) as sum_profit
from (select n_name as nation,
extract(year from o_orderdate) as o_year,

4
mysql-test/main/subselect2.result
View file

@ -125,8 +125,8 @@ DOCID DOCNAME DOCTYPEID FOLDERID AUTHOR CREATED TITLE SUBTITLE DOCABSTRACT PUBLI
c373e9f5ad07993f3859444553544200 Last Discussion c373e9f5ad079174ff17444553544200 c373e9f5ad0796c0eca4444553544200 Goldilocks 2003-06-09 11:21:06 Title: Last Discussion NULL Setting new abstract and keeping doc checked out 2003-06-09 10:51:26 2003-06-09 10:51:26 NULL NULL NULL 03eea05112b845949f3fd03278b5fe43 2003-06-09 11:21:06 admin 0 NULL Discussion NULL NULL
EXPLAIN SELECT t2.*, t4.DOCTYPENAME, t1.CONTENTSIZE,t1.MIMETYPE FROM t2 INNER JOIN t4 ON t2.DOCTYPEID = t4.DOCTYPEID LEFT OUTER JOIN t1 ON t2.DOCID = t1.DOCID WHERE t2.FOLDERID IN(SELECT t3_a.FOLDERID FROM t3 as t3_a WHERE t3_a.PARENTID IN(SELECT t3_b.FOLDERID FROM t3 as t3_b WHERE t3_b.PARENTID IN(SELECT t3_c.FOLDERID FROM t3 as t3_c WHERE t3_c.PARENTID IN(SELECT t3_d.FOLDERID FROM t3 as t3_d WHERE t3_d.PARENTID IN(SELECT t3_e.FOLDERID FROM t3 as t3_e WHERE t3_e.PARENTID='2f6161e879db43c1a5b82c21ddc49089' AND t3_e.FOLDERNAME = 'Level1') AND t3_d.FOLDERNAME = 'Level2') AND t3_c.FOLDERNAME = 'Level3') AND t3_b.FOLDERNAME = 'CopiedFolder') AND t3_a.FOLDERNAME = 'Movie Reviews') AND t2.DOCNAME = 'Last Discussion';
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t4 ALL PRIMARY NULL NULL NULL 10
1 PRIMARY t2 ALL DDOCTYPEID_IDX,DFOLDERID_IDX NULL NULL NULL 9 Using where; Using join buffer (flat, BNL join)
1 PRIMARY t2 ALL DDOCTYPEID_IDX,DFOLDERID_IDX NULL NULL NULL 9 Using where
1 PRIMARY t4 eq_ref PRIMARY PRIMARY 34 test.t2.DOCTYPEID 1
1 PRIMARY t1 eq_ref PRIMARY PRIMARY 34 test.t2.DOCID 1
1 PRIMARY t3_a eq_ref PRIMARY,FFOLDERID_IDX,CMFLDRPARNT_IDX PRIMARY 34 test.t2.FOLDERID 1 Using where
1 PRIMARY t3_b eq_ref PRIMARY,FFOLDERID_IDX,CMFLDRPARNT_IDX PRIMARY 34 test.t3_a.PARENTID 1 Using where

10
mysql-test/main/subselect_mat.result
View file

@ -1959,11 +1959,11 @@ EXPLAIN EXTENDED
SELECT * FROM t1
WHERE a IN (SELECT MAX(c) FROM t2) AND b=7 AND (a IS NULL OR a=b);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 100.00 Using where
1 PRIMARY <subquery2> const distinct_key distinct_key 4 const 1 100.00 Using where
1 PRIMARY <subquery2> const distinct_key distinct_key 4 const 1 100.00
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 100.00 Using where; Using join buffer (flat, BNL join)
2 MATERIALIZED t2 ALL NULL NULL NULL NULL 3 100.00
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from <materialize> (/* select#2 */ select max(`test`.`t2`.`c`) from `test`.`t2` having `MAX(c)` is null or `MAX(c)` = 7) join `test`.`t1` where `test`.`t1`.`b` = 7 and `<subquery2>`.`MAX(c)` = `test`.`t1`.`a` and (`test`.`t1`.`a` is null or `test`.`t1`.`a` = 7)
Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from <materialize> (/* select#2 */ select max(`test`.`t2`.`c`) from `test`.`t2` having `MAX(c)` is null or `MAX(c)` = 7) join `test`.`t1` where `test`.`t1`.`b` = 7 and `test`.`t1`.`a` = `<subquery2>`.`MAX(c)` and (<cache>(/*always not null*/ 1 is null) or `<subquery2>`.`MAX(c)` = 7)
SELECT * FROM t1
WHERE a IN (SELECT MAX(c) FROM t2) AND b=7 AND (a IS NULL OR a=b);
a b
@ -1972,8 +1972,8 @@ EXPLAIN
SELECT * FROM t1
WHERE a IN (SELECT MAX(c) FROM t2 WHERE c < 4) AND b=7 AND (a IS NULL OR a=b);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
1 PRIMARY <subquery2> const distinct_key distinct_key 4 const 1 Using where
1 PRIMARY <subquery2> const distinct_key distinct_key 4 const 1
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where; Using join buffer (flat, BNL join)
2 MATERIALIZED t2 ALL NULL NULL NULL NULL 3 Using where
SELECT * FROM t1
WHERE a IN (SELECT MAX(c) FROM t2 WHERE c < 4) AND b=7 AND (a IS NULL OR a=b);

20
mysql-test/main/subselect_sj.result
View file

@ -806,7 +806,7 @@ insert into t2 (pk) values (-1),(0);
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (a, b) IN (SELECT a, b FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`a` = `test`.`t1`.`a` and `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (a, b) IN (SELECT a, b FROM t2 WHERE pk > 0);
@ -815,7 +815,7 @@ pk
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, c) IN (SELECT b, c FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`c` = `test`.`t1`.`c` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (b, c) IN (SELECT b, c FROM t2 WHERE pk > 0);
@ -825,7 +825,7 @@ pk
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, d) IN (SELECT b, d FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`d` = `test`.`t1`.`d` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (b, d) IN (SELECT b, d FROM t2 WHERE pk > 0);
@ -834,7 +834,7 @@ pk
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, e) IN (SELECT b, e FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`e` = `test`.`t1`.`e` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (b, e) IN (SELECT b, e FROM t2 WHERE pk > 0);
@ -844,7 +844,7 @@ pk
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, f) IN (SELECT b, f FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`f` = `test`.`t1`.`f` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (b, f) IN (SELECT b, f FROM t2 WHERE pk > 0);
@ -854,7 +854,7 @@ pk
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, g) IN (SELECT b, g FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`g` = `test`.`t1`.`g` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (b, g) IN (SELECT b, g FROM t2 WHERE pk > 0);
@ -864,7 +864,7 @@ pk
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, h) IN (SELECT b, h FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`h` = `test`.`t1`.`h` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (b, h) IN (SELECT b, h FROM t2 WHERE pk > 0);
@ -874,7 +874,7 @@ pk
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, i) IN (SELECT b, i FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`i` = `test`.`t1`.`i` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (b, i) IN (SELECT b, i FROM t2 WHERE pk > 0);
@ -884,7 +884,7 @@ pk
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, j) IN (SELECT b, j FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`j` = `test`.`t1`.`j` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (b, j) IN (SELECT b, j FROM t2 WHERE pk > 0);
@ -894,7 +894,7 @@ pk
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, k) IN (SELECT b, k FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`k` = `test`.`t1`.`k` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (b, k) IN (SELECT b, k FROM t2 WHERE pk > 0);

20
mysql-test/main/subselect_sj_jcl6.result
View file

@ -817,7 +817,7 @@ insert into t2 (pk) values (-1),(0);
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (a, b) IN (SELECT a, b FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`a` = `test`.`t1`.`a` and `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (a, b) IN (SELECT a, b FROM t2 WHERE pk > 0);
@ -826,7 +826,7 @@ pk
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, c) IN (SELECT b, c FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`c` = `test`.`t1`.`c` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (b, c) IN (SELECT b, c FROM t2 WHERE pk > 0);
@ -836,7 +836,7 @@ pk
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, d) IN (SELECT b, d FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`d` = `test`.`t1`.`d` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (b, d) IN (SELECT b, d FROM t2 WHERE pk > 0);
@ -845,7 +845,7 @@ pk
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, e) IN (SELECT b, e FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`e` = `test`.`t1`.`e` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (b, e) IN (SELECT b, e FROM t2 WHERE pk > 0);
@ -855,7 +855,7 @@ pk
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, f) IN (SELECT b, f FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`f` = `test`.`t1`.`f` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (b, f) IN (SELECT b, f FROM t2 WHERE pk > 0);
@ -865,7 +865,7 @@ pk
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, g) IN (SELECT b, g FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`g` = `test`.`t1`.`g` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (b, g) IN (SELECT b, g FROM t2 WHERE pk > 0);
@ -875,7 +875,7 @@ pk
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, h) IN (SELECT b, h FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`h` = `test`.`t1`.`h` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (b, h) IN (SELECT b, h FROM t2 WHERE pk > 0);
@ -885,7 +885,7 @@ pk
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, i) IN (SELECT b, i FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`i` = `test`.`t1`.`i` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (b, i) IN (SELECT b, i FROM t2 WHERE pk > 0);
@ -895,7 +895,7 @@ pk
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, j) IN (SELECT b, j FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`j` = `test`.`t1`.`j` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (b, j) IN (SELECT b, j FROM t2 WHERE pk > 0);
@ -905,7 +905,7 @@ pk
EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, k) IN (SELECT b, k FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 100.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 50.00 Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
Warnings:
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where `test`.`t2`.`b` = `test`.`t1`.`b` and `test`.`t2`.`k` = `test`.`t1`.`k` and `test`.`t2`.`pk` > 0
SELECT pk FROM t1 WHERE (b, k) IN (SELECT b, k FROM t2 WHERE pk > 0);

10
mysql-test/main/subselect_sj_mat.result
View file

@ -1985,11 +1985,11 @@ EXPLAIN EXTENDED
SELECT * FROM t1
WHERE a IN (SELECT MAX(c) FROM t2) AND b=7 AND (a IS NULL OR a=b);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 100.00 Using where
1 PRIMARY <subquery2> const distinct_key distinct_key 4 const 1 100.00 Using where
1 PRIMARY <subquery2> const distinct_key distinct_key 4 const 1 100.00
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 100.00 Using where; Using join buffer (flat, BNL join)
2 MATERIALIZED t2 ALL NULL NULL NULL NULL 3 100.00
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from <materialize> (/* select#2 */ select max(`test`.`t2`.`c`) from `test`.`t2` having `MAX(c)` is null or `MAX(c)` = 7) join `test`.`t1` where `test`.`t1`.`b` = 7 and `<subquery2>`.`MAX(c)` = `test`.`t1`.`a` and (`test`.`t1`.`a` is null or `test`.`t1`.`a` = 7)
Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from <materialize> (/* select#2 */ select max(`test`.`t2`.`c`) from `test`.`t2` having `MAX(c)` is null or `MAX(c)` = 7) join `test`.`t1` where `test`.`t1`.`b` = 7 and `test`.`t1`.`a` = `<subquery2>`.`MAX(c)` and (<cache>(/*always not null*/ 1 is null) or `<subquery2>`.`MAX(c)` = 7)
SELECT * FROM t1
WHERE a IN (SELECT MAX(c) FROM t2) AND b=7 AND (a IS NULL OR a=b);
a b
@ -1998,8 +1998,8 @@ EXPLAIN
SELECT * FROM t1
WHERE a IN (SELECT MAX(c) FROM t2 WHERE c < 4) AND b=7 AND (a IS NULL OR a=b);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
1 PRIMARY <subquery2> const distinct_key distinct_key 4 const 1 Using where
1 PRIMARY <subquery2> const distinct_key distinct_key 4 const 1
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where; Using join buffer (flat, BNL join)
2 MATERIALIZED t2 ALL NULL NULL NULL NULL 3 Using where
SELECT * FROM t1
WHERE a IN (SELECT MAX(c) FROM t2 WHERE c < 4) AND b=7 AND (a IS NULL OR a=b);

3
sql/rowid_filter.cc
View file

@ -472,8 +472,7 @@ void Range_rowid_filter_cost_info::trace_info(THD *thd)
@param fetch_cost_factor The cost of fetching 'records' rows
@param index_only_cost The cost of fetching 'records' rows with
index only reads
@param prev_records How many row combinations we have in
preceding tables
@param prev_records How many index_read_calls() we expect to make
@parma records_out Will be updated to the minimum result rows for any
usable filter.
@details

386
sql/sql_select.cc
View file

@ -349,6 +349,9 @@ static void fix_items_after_optimize(THD *thd, SELECT_LEX *select_lex);
static void optimize_rownum(THD *thd, SELECT_LEX_UNIT *unit, Item *cond);
static bool process_direct_rownum_comparison(THD *thd, SELECT_LEX_UNIT *unit,
Item *cond);
static double prev_record_reads(const POSITION *positions, uint idx,
table_map found_ref, double record_count,
double *same_keys);
#ifndef DBUG_OFF
@ -8003,7 +8006,7 @@ apply_filter(THD *thd, TABLE *table, ALL_READ_COST *cost,
/* We are going to read 'selectivity' fewer rows */
adjusted_cost.row_cost.io*= selectivity;
adjusted_cost.row_cost.cpu*= selectivity;
adjusted_cost.copy_cost*= selectivity;
adjusted_cost.copy_cost*= selectivity; // Cost of copying row or key
adjusted_cost.index_cost.cpu+= filter_lookup_cost;
tmp= prev_records * WHERE_COST_THD(thd);
@ -8085,15 +8088,18 @@ struct best_plan
double records_read; // Records accessed
double records_after_filter; // Records_read + filter
double records_out; // Smallest record count seen
double prev_record_reads; // Save value from prev_record_reads
double identical_keys; // Save value from prev_record_reads
Range_rowid_filter_cost_info *filter; // Best filter
KEYUSE *key; // Best key
SplM_plan_info *spl_plan;
table_map ref_depends_map;
ulonglong refills; // Join cache refills
enum join_type type;
uint forced_index;
uint max_key_part;
table_map found_ref;
bool uses_jbuf;
bool use_join_buffer;
};
@ -8145,6 +8151,7 @@ best_access_path(JOIN *join,
best.records_read= DBL_MAX;
best.records_after_filter= DBL_MAX;
best.records_out= table->stat_records() * table->cond_selectivity;
best.prev_record_reads= best.identical_keys= 0;
best.filter= 0;
best.key= 0;
best.max_key_part= 0;
@ -8152,7 +8159,8 @@ best_access_path(JOIN *join,
best.forced_index= MAX_KEY;
best.found_ref= 0;
best.ref_depends_map= 0;
best.uses_jbuf= FALSE;
best.refills= 0;
best.use_join_buffer= FALSE;
best.spl_plan= 0;
disable_jbuf= disable_jbuf || idx == join->const_tables;
@ -8178,7 +8186,8 @@ best_access_path(JOIN *join,
KEYUSE *keyuse, *start_key= 0;
uint max_key_part=0;
enum join_type type= JT_UNKNOWN;
double cur_cost;
double cur_cost, copy_cost, cached_prev_record_reads= 0.0;
table_map cached_prev_ref= ~(table_map) 0;
/* Test how we can use keys */
rec= s->records/MATCHING_ROWS_IN_OTHER_TABLE; // Assumed records/key
@ -8202,6 +8211,8 @@ best_access_path(JOIN *join,
double startup_cost= s->startup_cost;
double records_after_filter, records_best_filter, records;
Range_rowid_filter_cost_info *filter= 0;
double prev_record_count= record_count;
double identical_keys= 0;
if (is_hash_join_key_no(key))
{
@ -8243,6 +8254,7 @@ best_access_path(JOIN *join,
If 1. expression does not refer to forward tables
2. we won't get two ref-or-null's
*/
double ignore;
all_parts|= keyuse->keypart_map;
if (!(remaining_tables & keyuse->used_tables) &&
(!keyuse->validity_ref || *keyuse->validity_ref) &&
@ -8259,13 +8271,19 @@ best_access_path(JOIN *join,
if (!keyuse->val->maybe_null() || keyuse->null_rejecting)
notnull_part|=keyuse->keypart_map;
double tmp2= prev_record_reads(join_positions, idx,
(found_ref | keyuse->used_tables));
if (tmp2 < best_prev_record_reads)
if ((found_ref | keyuse->used_tables) != cached_prev_ref)
{
cached_prev_ref= (found_ref | keyuse->used_tables);
cached_prev_record_reads=
prev_record_reads(join_positions, idx,
cached_prev_ref, record_count,
&ignore);
}
if (cached_prev_record_reads < best_prev_record_reads)
{
best_prev_record_reads= cached_prev_record_reads;
best_part_found_ref= (keyuse->used_tables &
~join->const_table_map);
best_prev_record_reads= tmp2;
}
if (rec > keyuse->ref_table_rows)
rec= keyuse->ref_table_rows;
@ -8363,7 +8381,6 @@ best_access_path(JOIN *join,
(!(key_flags & HA_NULL_PART_KEY) || // (2)
all_key_parts == notnull_part)) // (3)
{
double adjusted_cost;
/* Check that eq_ref_tables are correctly updated */
DBUG_ASSERT(join->eq_ref_tables & table->map);
type= JT_EQ_REF;
@ -8381,14 +8398,12 @@ best_access_path(JOIN *join,
tmp= cost_for_index_read(thd, table, key, 1, 1);
}
/*
Calculate an adjusted cost based on how many records are read
This will be multipled by record_count.
Calculate how many record read calls will be made taking
into account that we will cache the last read row.
*/
adjusted_cost= (prev_record_reads(join_positions, idx, found_ref) /
record_count);
set_if_smaller(adjusted_cost, 1.0);
tmp.row_cost.cpu*= adjusted_cost;
tmp.index_cost.cpu*= adjusted_cost;
prev_record_count= prev_record_reads(join_positions, idx,
found_ref, record_count,
&identical_keys);
records= 1.0;
}
else
@ -8751,22 +8766,34 @@ best_access_path(JOIN *join,
records,
file->cost(&tmp),
file->cost(tmp.index_cost),
record_count,
prev_record_count,
&records_best_filter);
set_if_smaller(best.records_out, records_best_filter);
if (filter)
filter= filter->apply_filter(thd, table, &tmp,
&records_after_filter,
&startup_cost,
1, record_count);
1, prev_record_count);
}
tmp.copy_cost+= records_after_filter * WHERE_COST_THD(thd);
cur_cost= file->cost_for_reading_multiple_times(record_count, &tmp);
cur_cost= COST_ADD(cur_cost, startup_cost);
/*
Take into account WHERE and setup cost.
We have to check the WHERE for all previous row combinations
(record_count).
'prev_record_count' is either 'record_count', or in case of
EQ_REF the estimated number of index_read() calls to the
engine when taking the one row read cache into account.
*/
copy_cost= (record_count * records_after_filter * WHERE_COST_THD(thd) +
startup_cost);
cur_cost= (file->cost_for_reading_multiple_times(prev_record_count, &tmp) +
copy_cost);
if (unlikely(trace_access_idx.trace_started()))
{
if (prev_record_count != record_count)
trace_access_idx.add("prev_record_count", prev_record_count);
trace_access_idx.
add("rows", records_after_filter).
add("cost", cur_cost);
@ -8796,6 +8823,8 @@ best_access_path(JOIN *join,
best.records_after_filter= ((use_cond_selectivity > 1) ?
records_after_filter :
records_best_filter);
best.prev_record_reads= prev_record_count;
best.identical_keys= identical_keys;
best.key= start_key;
best.found_ref= found_ref;
best.max_key_part= max_key_part;
@ -8908,9 +8937,10 @@ best_access_path(JOIN *join,
best.records= rnd_records;
best.key= hj_start_key;
best.ref_depends_map= 0;
best.uses_jbuf= TRUE;
best.use_join_buffer= TRUE;
best.filter= 0;
best.type= JT_HASH;
best.refills= (ulonglong) ceil(refills);
Json_writer_object trace_access_hash(thd);
if (unlikely(trace_access_hash.trace_started()))
trace_access_hash.
@ -8977,7 +9007,8 @@ best_access_path(JOIN *join,
const char *scan_type= "";
enum join_type type;
uint forced_index= MAX_KEY;
bool force_plan= 0;
bool force_plan= 0, use_join_buffer= 0;
ulonglong refills= 1;
/*
Range optimizer never proposes a RANGE if it isn't better
@ -9150,7 +9181,7 @@ best_access_path(JOIN *join,
s->cached_forced_index= forced_index;
}
if ((table->map & join->outer_join) || disable_jbuf)
if (disable_jbuf || (table->map & join->outer_join))
{
/*
Simple scan
@ -9169,7 +9200,7 @@ best_access_path(JOIN *join,
else
{
/* Scan trough join cache */
double cmp_time, row_copy_cost, refills;
double cmp_time, row_copy_cost, tmp_refills;
/*
Note that the cost of checking all rows against the table specific
@ -9178,10 +9209,11 @@ best_access_path(JOIN *join,
scan_type= "scan_with_join_cache";
/* Calculate cost of refills */
refills= (1.0 + floor((double) cache_record_length(join,idx) *
(record_count /
(double) thd->variables.join_buff_size)));
cur_cost= COST_MULT(cur_cost, refills);
tmp_refills= (1.0 + floor((double) cache_record_length(join,idx) *
(record_count /
(double) thd->variables.join_buff_size)));
cur_cost= COST_MULT(cur_cost, tmp_refills);
refills= (ulonglong) tmp_refills;
/* We come here only if there are already rows in the join cache */
DBUG_ASSERT(idx != join->const_tables);
@ -9201,6 +9233,7 @@ best_access_path(JOIN *join,
((idx - join->const_tables) * row_copy_cost +
WHERE_COST_THD(thd)));
cur_cost= COST_ADD(cur_cost, cmp_time);
use_join_buffer= 1;
}
}
@ -9259,8 +9292,8 @@ best_access_path(JOIN *join,
best.filter= filter;
/* range/index_merge/ALL/index access method are "independent", so: */
best.ref_depends_map= 0;
best.uses_jbuf= MY_TEST(!disable_jbuf && !((table->map &
join->outer_join)));
best.use_join_buffer= use_join_buffer;
best.refills= (ulonglong) ceil(refills);
best.spl_plan= 0;
best.type= type;
trace_access_scan.add("chosen", true);
@ -9286,6 +9319,8 @@ best_access_path(JOIN *join,
pos->records_after_filter= best.records_after_filter;
pos->records_read= best.records;
pos->records_out= best.records_out;
pos->prev_record_reads= best.prev_record_reads;
pos->identical_keys= best.identical_keys;
pos->read_time= best.cost;
pos->key= best.key;
pos->forced_index= best.forced_index;
@ -9293,11 +9328,12 @@ best_access_path(JOIN *join,
pos->table= s;
pos->ref_depend_map= best.ref_depends_map;
pos->loosescan_picker.loosescan_key= MAX_KEY;
pos->use_join_buffer= best.uses_jbuf;
pos->use_join_buffer= best.use_join_buffer;
pos->spl_plan= best.spl_plan;
pos->range_rowid_filter_info= best.filter;
pos->key_dependent= (best.type == JT_EQ_REF ? (table_map) 0 :
key_dependent & remaining_tables);
pos->refills= best.refills;
loose_scan_opt.save_to_position(s, record_count, pos->records_out,
loose_scan_pos);
@ -11571,89 +11607,241 @@ cache_record_length(JOIN *join,uint idx)
return length;
}
/*
Get the number of different row combinations for subset of partial join
Estimate the number of engine ha_index_read_calls for EQ_REF tables
when taking into account the one-row-cache in join_read_always_key()
SYNOPSIS
prev_record_reads()
join The join structure
idx Number of tables in the partial join order (i.e. the
partial join order is in join->positions[0..idx-1])
found_ref Bitmap of tables for which we need to find # of distinct
row combinations.
@param position All previous tables best_access_path() information.
@param idx Number of (previous) tables in positions.
@param record_count Number of incoming record combinations
@param found_ref Bitmap of tables that is used to construct the key
used with the index read.
@return # The number of estimated calls that cannot be cached by the
the one-row-cache. In other words, number of expected
calls to engine ha_read_read_map().
Between 1 and record_count or 0 if record_count == 0
DESCRIPTION
Given a partial join order (in join->positions[0..idx-1]) and a subset of
tables within that join order (specified in found_ref), find out how many
distinct row combinations of subset tables will be in the result of the
partial join order.
This is used as follows: Suppose we have a table accessed with a ref-based
method. The ref access depends on current rows of tables in found_ref.
We want to count # of different ref accesses. We assume two ref accesses
will be different if at least one of access parameters is different.
Example: consider a query
The one-row-cache gives a great benefit when there are multiple consecutive
calls to ha_index_read() with the same key. In this case we can skip
calling the engine (and in the future also skip to check the key
condition), which can notably increase the performance.
SELECT * FROM t1, t2, t3 WHERE t1.key=c1 AND t2.key=c2 AND t3.key=t1.field
Assuming most of the rows are cached, there is no notable saving to be
made trying to calculate the total number of distinct key values that will
be used. The performance of a ha_index_read_call() is about the same even
if we repeatedly read the same set of rows.
and a join order:
t1, ref access on t1.key=c1
t2, ref access on t2.key=c2
t3, ref access on t3.key=t1.field
For t1: n_ref_scans = 1, n_distinct_ref_scans = 1
For t2: n_ref_scans = records_read(t1), n_distinct_ref_scans=1
For t3: n_ref_scans = records_read(t1)*records_read(t2)
n_distinct_ref_scans = #records_read(t1)
The reason for having this function (at least the latest version of it)
is that we need to account for buffering in join execution.
An edge-case example: if we have a non-first table in join accessed via
ref(const) or ref(param) where there is a small number of different
values of param, then the access will likely hit the disk cache and will
not require any disk seeks.
The proper solution would be to assume an LRU disk cache of some size,
calculate probability of cache hits, etc. For now we just count
identical ref accesses as one.
This code works by calculating the number of identical key sequences
found in the record stream.
The number of expected distinct calls can then be calculated as
records_count / sequences.
RETURN
Expected number of row combinations
Some things to note:
- record_count == PRODUCT(records_out) over all tables[0...idx-1]
- position->prev_record_reads contains the number of identical
sequences found for previous EQ_REF tables.
Assume a join prefix of t1,t2,t3,t4 and t4 is an EQ_REF table.
We have the following combinations that we have to consider:
======
1) No JOIN_CACHE usage, tables depend only on one previous table
Row combinations are generated as:
- for all rows in t1
- for all rows in t2
- for all rows in t3
or
t1.1,t2.1,t3.1, t1.1,t2.1,t3.2, t1.1,t2.1,t3.3... # Only t3 row changes
(until no more rows in t3., ie t3.records_out times)
t1.1,t2.2,t3.1, t1.1,t2.2,t3.2, t1.1,t2.2,t3.3... # t2.2 read
(above repeated until no more rows in t2 and t3)
t1.2,t2.1,t3.1, t1.2,t2.1,t3.2, t1.2,t2.1,t3.3... # t1.2 read
If t4 is an EQ_REF table that is depending of one of the
previous tables, the number of identical keys can be calculated
as the multiplication of records_out of the tables in between
the t4 and its first dependency.
Let's consider cases where t4 depends on different previous tables:
WHERE t4.a=t3.a
no caching as t3 can change for each row
engine_calls: record_count
WHERE t4.a=t2.a
t4 is not depending on t3. The number of repeated rows are:
t1.1,t2.1,t3.1 to t1.1,t2.1,t3.last # t3.records_out rows
t1.1,t2.2,t3.1 to t1.1,t2.2,t3.last # t3.records_out rows
...
t1.2,t2.1,t3.1 to t1.2,t2.1,t3.last
...
t1.last,t2.last.t3.1 to t1.last,t2.last.1,t3.last
For each combination of t1 and t2 there are t3.records_out repeated
rows with equal key value
engine_calls: record_count / t3.records_out calls =
t1.records_out * t2.records_out
WHERE t4.a=t1.a
The repeated sequences:
t1.1,t2.1,t3.1 to t1.1,t2.last,t3.last
t1.2,t2.1,t3.1 to t2.1,t2.last,t3.last
repeated rows: t2.records_out * t3.records_out
engine_calls: record_count/repeated_rows = t1.records_out
If t4 depends on a table that uses EQ_REF access, we can multipy that
table's repeated_rows with current table's repeated_rows to take that
into account.
=====
2) Keys depending on multiple tables
In this case we have to stop searching after we find the first
table we depend upon.
We have to also disregard the number of repeated rows for the
found table. This can be seen from (assuming tables t1...t6):
WHERE t6.a=t4.a and t6.a=t3.a and t4.a= t2.a
- Here t4 is not depending on t3 (and thus there is a
t3.records_out identical keys for t4). However t6 key will
change for each t3 row and t6 cannot thus use
t3.identical_keys
WHERE t4.key_part1=t1.a and t4.key_part2= t3.a
As t4.key_part2 will change for every row, one-row-cache will not
be hit
WHERE t4.key_part1=t1.a and t4.key_part2= t2.a
t4.key will change when t1 or t2 changes
This is the same case as above for WHERE t4.a = t2.a
engine_calls: record_count / t3.records_out calls
=====
3) JOIN_CACHE is used
If any table is using join_cache as this changes the row
combinations seen by following tables. Using join cache for a
table T# will have T# rows repeated for the next table as many
times there are combinations in the cache. The the cache will
re-read and the operations repeats 'refill-1' number of times.
Table rows from table just before T# will come in 'random order',
from the point of the next tables.
Assuming t3 is using a cache, t4 will see the rows coming in the
following order:
t1.1,t2.1,t3.1, t1.1,t2.2,t3.1, t1.1,t2.3,t3.1...
(t3.1 repeated 't2.records_out' times)
t1.2,t2.1,t3.1, t1.2,t2.2,t3.1, t1.2,t2.3,t3.1...
(Next row in t1 used)
t1.1,t2.1,t3.2, t1.1,t2.2,t3.2, t1.1,t2.3,t3.2...
(Restarting all t1 & t2 combinations for t3.2)
WHERE t4.a=t3.a
- There is a repeated sequence of t3.records_out rows for
each t1,t2 row combination.
engine_calls= record_count / t3.records_out
WHERE t4.a=t2.a
t2 changes for each row
engine_calls= record_count
WHERE t4.a=t1.a
repeated rows= t2.records_out
engine_calls= record_count / t2.records_out
A refill of the join cache will restart the row sequences
(we have 'refill' more sequences), so we will have to do 'refill' times
more engine read calls.
=====
Expectations of the accuracy of the return value
- The value is always between 1 and record_count
- The returned value should almost always larger than the true number of
engine calls.
- Assuming that every row has different values for all other columns for
echo unique key value and record_count is accurate:
- If a table is depending on multiple tables, the return value may be
notable larger than real value.
- If there is no join cache the value should be exact.
- If there is a join cache, but no refills calculated or done then
the value should be exact.
- If there was more join_cache refills than was calculated, the value
may be slightly to low.
- If the number of refills is equal or less than was calculated the value
should be larger than the expected engine read calls. The more refills,
the less exact the number will be.
*/
double
prev_record_reads(const POSITION *positions, uint idx, table_map found_ref)
static double
prev_record_reads(const POSITION *position, uint idx, table_map found_ref,
double record_count, double *identical_keys)
{
double found=1.0;
const POSITION *pos_end= positions - 1;
for (const POSITION *pos= positions + idx - 1; pos != pos_end; pos--)
double found= 1.0;
const POSITION *pos_end= position - 1;
const POSITION *cur_pos= position + idx;
/* Safety against const tables */
if (unlikely(!found_ref))
goto end;
for (const POSITION *pos= cur_pos-1; pos != pos_end; pos--)
{
if (pos->table->table->map & found_ref)
if (found_ref & pos->table->table->map)
{
found_ref|= pos->ref_depend_map;
/*
For the case of "t1 LEFT JOIN t2 ON ..." where t2 is a const table
with no matching row we will get position[t2].records_read==0.
Actually the size of output is one null-complemented row, therefore
we will use value of 1 whenever we get records_read==0.
Note
- the above case can't occur if inner part of outer join has more
than one table: table with no matches will not be marked as const.
- Ideally we should add 1 to records_read for every possible null-
complemented row. We're not doing it because: 1. it will require
non-trivial code and add overhead. 2. The value of records_read
is an inprecise estimate and adding 1 (or, in the worst case,
#max_nested_outer_joins=64-1) will not make it any more precise.
/* Found a table we depend on */
found_ref= ~pos->table->table->map;
if (!found_ref)
{
/*
No more dependencies. We can use the cached values to improve things
a bit
*/
if (pos->type == JT_EQ_REF)
found= COST_MULT(found, pos->identical_keys);
else if (pos->use_join_buffer)
found= COST_MULT(found, pos->loops / pos->refills);
}
break;
}
if (unlikely(pos->use_join_buffer))
{
/* Each refill can change the cached key */
found/= pos->refills;
}
else
{
/*
We are not depending on the current table.
There are 'records_out' rows with identical rows
value for our depending tables.
*/
if (pos->records_out)
found= COST_MULT(found, pos->records_out);
found= COST_MULT(found, pos->records_out);
}
}
return found;
/*
In most case found should <= record_count.
However if there was a reduction of rows (records_out < 1) before
the referencing table then found could be >= record_count.
To get resonable numbers, we limit prev_record_read to be between
1.0 and record_count as we have to always do at least one read
anyway.
*/
end:
if (unlikely(found > record_count))
found= record_count;
if (unlikely(found <= 1.0))
found= 1.0;
*identical_keys= found;
return record_count / found;
}

7
sql/sql_select.h
View file

@ -410,7 +410,7 @@ typedef struct st_join_table {
uint index;
uint status; ///< Save status for cache
uint used_fields;
uint cached_covering_key; /* Set by estimate_scan_time() */
uint cached_covering_key; // Set by estimate_scan_time()
ulong used_fieldlength;
ulong max_used_fieldlength;
uint used_blobs;
@ -1012,6 +1012,9 @@ public:
*/
double records_out;
/* Values from prev_record_reads call for EQ_REF table*/
double prev_record_reads, identical_keys;
/* The selectivity of the pushed down conditions */
double cond_selectivity;
@ -1061,6 +1064,7 @@ public:
LooseScan_picker loosescan_picker;
Sj_materialization_picker sjmat_picker;
ulonglong refills;
/*
Current optimization state: Semi-join strategy to be used for this
and preceding join tables.
@ -2537,7 +2541,6 @@ bool instantiate_tmp_table(TABLE *table, KEY *keyinfo,
TMP_ENGINE_COLUMNDEF **recinfo,
ulonglong options);
bool open_tmp_table(TABLE *table);
double prev_record_reads(const POSITION *positions, uint idx, table_map found_ref);
void fix_list_after_tbl_changes(SELECT_LEX *new_parent, List<TABLE_LIST> *tlist);
void optimize_keyuse(JOIN *join, DYNAMIC_ARRAY *keyuse_array);
bool sort_and_filter_keyuse(JOIN *join, DYNAMIC_ARRAY *keyuse,

466
tests/prev_record.cc Normal file
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/* Copyright (c) 2023 MariaDB Corporation
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */
/*
This program simulates the MariaDB query process execution using
the SCAN, EQ_REF, REF and join_cache (CACHE) row lookup methods.
The purpose is to verify that 'prev_record_reads()' function correctly
estimates the number of lookups we have to do for EQ_REF access
assuming we have 'one-row-cache' before the lookup.
The logic for the prev_record_reads() function in this file should
match the logic in sql_select.cc::prev_record_reads() in MariaDB 11.0
and above.
The program generates first a randomized plan with the above
methods, then executes a full 'query' processing and then lastly
checks that the number of EQ_REF engine lookups matches the
estimated number of lookups.
If the number of estimated lookups are not exact, the plan and
lookup numbers are printed. That a plan is printed is not to be
regarded as a failure. It's a failure only of the number of engine
calls are far greater than the number of estimated lookups.
Note that the estimated number of lookups are exact only if CACHE
refills == 1 and if the EQ_REF table only depends on one earlier
table.
*/
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <time.h>
#define TABLES 21
#define DEFAULT_TABLES 10
#define CACHED_ROWS 10000
#define unlikely(A) A
enum JOIN_TYPE { SCAN, EQ_REF, REF, CACHE };
const char *type[]= { "SCAN", "EQ_REF", "REF", "CACHE"};
typedef unsigned long long DEPEND;
typedef unsigned int uint;
typedef unsigned long long ulonglong;
struct TABLE
{
ulonglong data;
JOIN_TYPE type;
DEPEND map;
DEPEND ref_depend_map;
uint records_in_table;
uint matching_records;
uint last_key;
ulonglong lookups;
ulonglong *cache; // join cache
ulong cached_records;
ulong flushed_caches;
};
struct POSITION
{
TABLE *table;
JOIN_TYPE type;
double records;
double record_count;
double records_out;
double prev_record_read;
double same_keys;
ulong refills;
};
uint opt_tables= DEFAULT_TABLES;
bool verbose=0;
uint rand_init;
struct TABLE table[TABLES];
struct POSITION positions[TABLES];
void do_select(uint table_index);
static void
prev_record_reads(POSITION *position, uint idx, DEPEND found_ref,
double record_count)
{
double found= 1.0;
POSITION *pos_end= position - 1;
POSITION *cur_pos= position + idx;
/* Safety against const tables */
if (!found_ref)
goto end;
for (POSITION *pos= cur_pos-1; pos != pos_end; pos--)
{
if (found_ref & pos->table->map)
{
found_ref&= ~pos->table->map;
/* Found depent table */
if (pos->type == EQ_REF)
{
if (!found_ref)
found*= pos->same_keys;
}
else if (pos->type == CACHE)
{
if (!found_ref)
found*= pos->record_count / pos->refills;
}
break;
}
if (pos->type != CACHE)
{
/*
We are not depending on the curren table
There are 'records_out' rows with idenitical rows
value for our depending tables.
We are ignoring join_cache as in this case the
preceding tables row combination can change for
each call.
*/
found*= pos->records_out;
}
else
found/= pos->refills;
}
end:
cur_pos->record_count= record_count;
cur_pos->same_keys= found;
assert(record_count >= found);
if (unlikely(found <= 1.0))
cur_pos->prev_record_read= record_count;
else if (unlikely(found > record_count))
cur_pos->prev_record_read=1;
else
cur_pos->prev_record_read= record_count / found;
return;
}
void cleanup()
{
for (uint i= 0; i < opt_tables ; i++)
{
free(table[i].cache);
table[i].cache= 0;
}
}
void intialize_tables()
{
int eq_ref_tables;
restart:
eq_ref_tables= 0;
for (uint i= 0; i < opt_tables ; i++)
{
if (i == 0)
table[i].type= SCAN;
else
table[i].type= (JOIN_TYPE) (rand() % 4);
table[i].records_in_table= rand() % 5+3;
table[i].matching_records= 2 + rand() % 3;
table[i].map= (DEPEND) 1 << i;
table[i].ref_depend_map= 0;
/* The following is for testing */
#ifdef FORCE_COMB
if (i == 5 || i == 6)
{
table[i].type= REF;
table[i].matching_records= 5;
}
#endif
if (table[i].type != SCAN)
{
/* This just to make do_select a bit easier */
table[i].ref_depend_map= ((DEPEND) 1) << (rand() % i);
if (rand() & 1)
{
uint second_depend= rand() % i;
if (!(table[i].ref_depend_map & second_depend))
table[i].ref_depend_map|= ((DEPEND) 1) << second_depend;
}
}
if (table[i].type == EQ_REF)
{
table[i].matching_records= 1;
eq_ref_tables++;
}
else if (table[i].type != REF)
table[i].matching_records= table[i].records_in_table;
table[i].last_key= 0;
table[i].lookups= 0;
table[i].cached_records= 0;
table[i].flushed_caches= 0;
table[i].cache= 0;
if (table[i].type == CACHE)
table[i].cache= (ulonglong*) malloc(CACHED_ROWS *
sizeof(table[i].data) * i);
}
/* We must have at least one EQ_REF table */
if (!eq_ref_tables)
{
cleanup();
goto restart;
}
}
void optimize_tables()
{
double record_count= 1.0, records;
for (uint i= 0; i < opt_tables ; i++)
{
TABLE *tab= table+i;
positions[i].refills= 0;
switch (tab->type) {
case SCAN:
records= tab->records_in_table;
break;
case EQ_REF:
records= 1.0;
prev_record_reads(positions, i, tab->ref_depend_map, record_count);
break;
case REF:
records= tab->matching_records;
break;
case CACHE:
records= tab->records_in_table;
positions[i].refills= (record_count + CACHED_ROWS-1)/ CACHED_ROWS;
break;
default:
assert(0);
}
positions[i].table= table + i;
positions[i].type= table[i].type;
positions[i].records= records;
positions[i].record_count= record_count;
positions[i].records_out= records;
record_count*= records;
}
}
void process_join_cache(TABLE *tab, uint table_index)
{
if (!tab->cached_records)
return;
#ifdef PRINT_CACHE
putc('>', stdout);
for (uint k= 0 ; k < table_index ; k++)
{
printf("%8lld ", tab->cache[k]);
}
putc('\n',stdout);
putc('<', stdout);
for (uint k= 0 ; k < table_index ; k++)
{
printf("%8lld ", tab->cache[k+(tab->cached_records-1)*table_index]);
}
putc('\n',stdout);
#endif
for (uint k= 0 ; k < tab->records_in_table; k++)
{
table[table_index].data= k+1;
ulonglong *cache= tab->cache;
for (uint i= 0 ; i < tab->cached_records ; i++)
{
for (uint j= 0 ; j < table_index ; j++)
table[j].data= *cache++;
do_select(table_index+1);
}
}
tab->flushed_caches++;
tab->cached_records= 0;
}
/*
Calculate a key depending on multiple tables
*/
ulonglong calc_ref_key(DEPEND depend_map)
{
ulonglong value= 1;
TABLE *t= table;
do
{
if (t->map & depend_map)
{
depend_map&= ~t->map;
value*= t->data;
}
t++;
} while (depend_map);
return value;
}
void do_select(uint table_index)
{
if (table_index == opt_tables)
return;
TABLE *tab= table + table_index;
switch (tab->type) {
case SCAN:
for (uint i= 1 ; i <= tab->records_in_table ; i++)
{
tab->data= i;
do_select(table_index+1);
}
break;
case REF:
{
ulonglong ref_key= calc_ref_key(tab->ref_depend_map);
for (uint i=1 ; i <= tab->matching_records ; i++)
{
tab->data= ref_key * tab->matching_records + i;
do_select(table_index+1);
}
break;
}
case EQ_REF:
{
ulonglong ref_key= calc_ref_key(tab->ref_depend_map);
if (ref_key != tab->last_key)
{
tab->lookups++;
#ifdef PRINT_EQ_KEY
if (table_index == 9)
printf("ref_key: %lld\n", ref_key);
#endif
tab->last_key= ref_key;
tab->data= ref_key * tab->matching_records;
}
else
{
assert(tab->lookups != 0);
}
do_select(table_index+1);
break;
}
case CACHE:
{
ulonglong *cache= tab->cache + tab->cached_records * table_index;
for (uint i= 0 ; i <= table_index ; i++)
*cache++ = table[i].data;
if (++tab->cached_records == CACHED_ROWS)
process_join_cache(tab, table_index);
break;
}
default:
break;
}
return;
}
void do_select_end(uint table_index)
{
if (table_index == opt_tables)
return;
TABLE *tab= table + table_index;
switch (tab->type) {
case CACHE:
process_join_cache(tab, table_index);
break;
default:
break;
}
do_select_end(table_index+1);
}
void execute()
{
do_select(0);
do_select_end(0);
}
int check_prev_records()
{
int errors= 0;
for (uint i= 0; i < opt_tables ; i++)
{
TABLE *tab= table + i;
if (tab->type == EQ_REF)
{
if (positions[i].prev_record_read != (double) tab->lookups)
{
fprintf(stdout, "table: %d lookups: %lld prev_record_read: %g\n",
i, tab->lookups, positions[i].prev_record_read);
errors++;
}
}
}
if (errors || verbose)
{
fprintf(stdout, "tables: %u\n", opt_tables);
fprintf(stdout, "rand_init: %u\n", rand_init);
fprintf(stdout, "cache_size: %u\n", (uint) CACHED_ROWS);
for (uint i= 0; i < opt_tables ; i++)
{
TABLE *tab= table + i;
fprintf(stdout, "table: %2d (%3lx) type: %-6s comb: %3lg out: %2lg lookups: %lld prev: %lg depend: %llx\n",
i, (uint) 1 << i, type[tab->type], positions[i].record_count,
positions[i].records_out, tab->lookups,
positions[i].prev_record_read, tab->ref_depend_map);
}
}
return errors;
}
int main(int argc, char **argv)
{
if (argc > 1)
{
opt_tables=atoi(argv[1]);
if (opt_tables <= 3)
opt_tables= 3;
if (opt_tables > TABLES)
opt_tables= TABLES;
}
if (argc > 2)
rand_init= atoi(argv[2]);
else
rand_init= (uint) time(0);
srand(rand_init);
intialize_tables();
optimize_tables();
execute();
cleanup();
exit(check_prev_records() > 0);
}