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| author | unknown <igor@olga.mysql.com> | 2007-08-02 12:45:56 -0700 |
|---|---|---|
| committer | unknown <igor@olga.mysql.com> | 2007-08-02 12:45:56 -0700 |
| commit | c90493749aa8736c76b5765cda0ca925864bbe37 (patch) | |
| tree | cb69ff6598e568046e57c591baf10d4a49f2d5b7 /sql/sql_select.h | |
| parent | baf24e69daf32141dda59b6d7fe817cc688b9f88 (diff) | |
| download | mariadb-git-c90493749aa8736c76b5765cda0ca925864bbe37.tar.gz | |
Fixed bug#28404.
This patch adds cost estimation for the queries with ORDER BY / GROUP BY
and LIMIT.
If there was a ref/range access to the table whose rows were required
to be ordered in the result set the optimizer always employed this access
though a scan by a different index that was compatible with the required
order could be cheaper to produce the first L rows of the result set.
Now for such queries the optimizer makes a choice between the cheapest
ref/range accesses not compatible with the given order and index scans
compatible with it.
mysql-test/r/distinct.result:
Adjusted results for test cases affected fy the fix for bug #28404.
mysql-test/r/endspace.result:
Adjusted results for test cases affected fy the fix for bug #28404.
mysql-test/r/group_by.result:
Adjusted results for test cases affected fy the fix for bug #28404.
mysql-test/r/group_min_max.result:
Adjusted results for test cases affected fy the fix for bug #28404.
mysql-test/r/innodb.result:
Adjusted results for test cases affected fy the fix for bug #28404.
mysql-test/r/innodb_mysql.result:
Adjusted results for test cases affected fy the fix for bug #28404.
mysql-test/r/merge.result:
Adjusted results for test cases affected fy the fix for bug #28404.
mysql-test/r/order_by.result:
Added a test case for bug #28404.
mysql-test/r/select_found.result:
Adjusted results for test cases affected fy the fix for bug #28404.
mysql-test/r/subselect.result:
Adjusted results for test cases affected fy the fix for bug #28404.
mysql-test/t/distinct.test:
Changed a test case after adding the fix for bug #28404.
mysql-test/t/order_by.test:
Added a test case for bug #28404.
sql/sql_select.cc:
Fixed bug#28404.
This patch adds cost estimation for the queries with ORDER BY / GROUP BY
and LIMIT.
Now for such queries the optimizer makes a choice between the cheapest
ref/range accesses not compatible with the given order and index scans
compatible with it.
Modified the function test_if_skip_sort_order to make the above mentioned
choice cost based.
sql/sql_select.h:
Fixed bug#28404.
This patch adds cost estimation for the queries with ORDER BY / GROUP BY
and LIMIT.
Added a new field fot the JOIN_TAB structure.
Diffstat (limited to 'sql/sql_select.h')
| -rw-r--r-- | sql/sql_select.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/sql/sql_select.h b/sql/sql_select.h index 98f2a7829dd..61df43094c2 100644 --- a/sql/sql_select.h +++ b/sql/sql_select.h @@ -194,6 +194,12 @@ typedef struct st_join_table { enum join_type type; bool cached_eq_ref_table,eq_ref_table,not_used_in_distinct; bool sorted; + /* + If it's not 0 the number stored this field indicates that the index + scan has been chosen to access the table data and we expect to scan + this number of rows for the table. + */ + ha_rows limit; TABLE_REF ref; JOIN_CACHE cache; JOIN *join; |