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Make EXPLAIN better at displaying MRR/BKA:

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- "Using MRR" is no longer shown with range access.
- Instead, both range and BKA accesses will show one of the following:
  = "Rowid-ordered scan"
  = "Key-ordered scan"
  = "Key-ordered Rowid-ordered scan"
depending on whether DS-MRR implementation will do scan keys in order, rowids in order,
or both.
- The patch also introduces a way for other storage engines/MRR implementations to
  pass information to EXPLAIN output about the properties of employed MRR scans.
This commit is contained in:
Sergey Petrunya
2011-04-02 14:04:45 +04:00
parent 886d84d6d1
commit 997445bc8e
46 changed files with 624 additions and 467 deletions
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8
mysql-test/r/innodb_mrr.result
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@@ -184,7 +184,7 @@ explain
select * from t4 where a IS NULL and b IS NULL and (c IS NULL or c='no-such-row1'
or c='no-such-row2');
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t4 range idx1 idx1 29 NULL 16 Using index condition; Using MRR
1 SIMPLE t4 range idx1 idx1 29 NULL 16 Using index condition; Rowid-ordered scan
select * from t4 where a IS NULL and b IS NULL and (c IS NULL or c='no-such-row1'
or c='no-such-row2');
a b c filler
@@ -206,7 +206,7 @@ NULL NULL NULL NULL-1
explain
select * from t4 where (a ='b-1' or a='bb-1') and b IS NULL and (c='c-1' or c='cc-2');
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t4 range idx1 idx1 29 NULL 32 Using index condition; Using MRR
1 SIMPLE t4 range idx1 idx1 29 NULL 32 Using index condition; Rowid-ordered scan
select * from t4 where (a ='b-1' or a='bb-1') and b IS NULL and (c='c-1' or c='cc-2');
a b c filler
b-1 NULL c-1 NULL-15
@@ -309,7 +309,7 @@ from t1 A, t1 B, t1 C;
explain
select count(length(a) + length(filler)) from t2 where a>='a-1000-a' and a <'a-1001-a';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range a a 9 NULL 99 Using index condition; Using MRR
1 SIMPLE t2 range a a 9 NULL 99 Using index condition; Rowid-ordered scan
select count(length(a) + length(filler)) from t2 where a>='a-1000-a' and a <'a-1001-a';
count(length(a) + length(filler))
100
@@ -319,7 +319,7 @@ filler char(10), key(d), primary key (a,b,c)) engine= innodb;
insert into t2 select A.a, B.a, B.a, A.a, 'filler' from t1 A, t1 B;
explain select * from t2 force index (d) where d < 10;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range d d 5 NULL # Using index condition; Using MRR
1 SIMPLE t2 range d d 5 NULL # Using index condition; Rowid-ordered scan
drop table t2;
drop table t1;
set @@mrr_buffer_size= @mrr_buffer_size_save;