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BUG#29740: Wrong query results for index_merge/union over HEAP table.

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- return HA_KEY_SCAN_NOT_ROR flag for HASH indexes;
- Fix ha_heap::cmp_ref() to work with BTREE index scans.


mysql-test/r/index_merge.result:
  BUG#29740: testcase
mysql-test/t/index_merge.test:
  BUG#29740: testcase
sql/ha_heap.h:
  BUG#29740: Wrong query results for index_merge/union over HEAP table.
  - make HEAP table engine return HA_KEY_SCAN_NOT_ROR flag for HASH 
    indexes,as HASH index does not guarantee any ordering for rows
    within the hash bucket.
  - Fix BTREE indexes: make ha_heap::cmp_ref() compare the rowids in the 
    same way as ha_key_cmp() does.
sql/opt_range.cc:
  BUG#29740: Fix comment about ROR scans.
This commit is contained in:
unknown
2007-07-13 19:13:40 +04:00
parent db84ffa351
commit 38f4c6137a
4 changed files with 118 additions and 19 deletions
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25
sql/opt_range.cc
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@@ -6007,27 +6007,24 @@ check_quick_keys(PARAM *param,uint idx,SEL_ARG *key_tree,
ROR (Rowid Ordered Retrieval) key scan is a key scan that produces
ordered sequence of rowids (ha_xxx::cmp_ref is the comparison function)
An index scan is a ROR scan if it is done using a condition in form
This function is needed to handle a practically-important special case:
an index scan is a ROR scan if it is done using a condition in form
"key1_1=c_1 AND ... AND key1_n=c_n" (1)
"key1_1=c_1 AND ... AND key1_n=c_n"
where the index is defined on (key1_1, ..., key1_N [,a_1, ..., a_n])
and the table has a clustered Primary Key
and the table has a clustered Primary Key defined as
PRIMARY KEY(a_1, ..., a_n, b1, ..., b_k) with first key parts being
identical to uncovered parts ot the key being scanned (2)
Scans on HASH indexes are not ROR scans,
any range scan on clustered primary key is ROR scan (3)
Check (1) is made in check_quick_keys()
Check (3) is made check_quick_select()
Check (2) is made by this function.
PRIMARY KEY(a_1, ..., a_n, b1, ..., b_k)
i.e. the first key parts of it are identical to uncovered parts ot the
key being scanned. This function assumes that the index flags do not
include HA_KEY_SCAN_NOT_ROR flag (that is checked elsewhere).
RETURN
TRUE If the scan is ROR-scan
FALSE otherwise
TRUE The scan is ROR-scan
FALSE Otherwise
*/
static bool is_key_scan_ror(PARAM *param, uint keynr, uint8 nparts)