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Bug#17588348: INDEX MERGE USED ON PARTITIONED TABLE

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CAN RETURN WRONG RESULT SET

PROBLEM
-------
In ha_partition::cmp_ref() we were only calling the 
underlying cmp_ref() of storage engine if the records
are in the same partiton,else we sort by partition and
returns the result.But the index merge intersect 
algorithm expects first to sort by row-id first and 
then by partition id.

FIX
---
Compare the refernces first using storage engine cmp_ref
and then if references are equal(only happens if 
non clustered index is used) then sort it by partition id.

[Approved by Mattiasj #rb3755]
-
This commit is contained in:
Aditya A 2013-11-05 19:25:26 +05:30
parent 175085e7d2
commit 097a5b59ed
1 changed files with 17 additions and 7 deletions
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24
sql/ha_partition.cc
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@ -7485,19 +7485,29 @@ uint ha_partition::min_record_length(uint options) const
int ha_partition::cmp_ref(const uchar *ref1, const uchar *ref2)
{
uint part_id;
int cmp;
my_ptrdiff_t diff1, diff2;
handler *file;
DBUG_ENTER("ha_partition::cmp_ref");
cmp = m_file[0]->cmp_ref((ref1 + PARTITION_BYTES_IN_POS),
(ref2 + PARTITION_BYTES_IN_POS));
if (cmp)
DBUG_RETURN(cmp);
if ((ref1[0] == ref2[0]) && (ref1[1] == ref2[1]))
{
part_id= uint2korr(ref1);
file= m_file[part_id];
DBUG_ASSERT(part_id < m_tot_parts);
DBUG_RETURN(file->cmp_ref((ref1 + PARTITION_BYTES_IN_POS),
(ref2 + PARTITION_BYTES_IN_POS)));
/* This means that the references are same and are in same partition.*/
DBUG_RETURN(0);
}
/*
In Innodb we compare with either primary key value or global DB_ROW_ID so
it is not possible that the two references are equal and are in different
partitions, but in myisam it is possible since we are comparing offsets.
Remove this assert if DB_ROW_ID is changed to be per partition.
*/
DBUG_ASSERT(!m_innodb);
diff1= ref2[1] - ref1[1];
diff2= ref2[0] - ref1[0];
if (diff1 > 0)