join_cache_level=6+
The patch fixes two similar bugs in the commit 8eeb689e9f
that added multi_range_read support to partitions. The commit opened
a possibility to join a partition table using BKA+MRR. However in some
cases it could lead to wrong results or even crashes.
This could happened when
- index condition pushdown was used to join the table or
- the joined table was an inner table of an outer join and 'not exist'
optimization was applied or
- the join table was the inner table of a semi-join and the first match
optimization was applied
The bugs were in the code of the call-back functions
- partition_multi_range_key_skip_record() and
- partition_multi_range_key_skip_index_tuple().
Each of this function consist only of an invocation of another function.
Yet a wrong parameter was passed at this invocation.
The fix was suggested by Sergey Petrunia and it is apparently in line
with original design.
The corresponding comprehensive test cases demonstrating the problems
caused by the bugs were constructed by me.
Fix partitioning and DS-MRR to work together
- In ha_partition::index_end(): take into account that ha_innobase (and
other engines using DS-MRR) will have inited=RND when initialized for
DS-MRR scan.
- In ha_partition::multi_range_read_next(): if the MRR scan is using
HA_MRR_NO_ASSOCIATION mode, it is not guaranteed that the partition's
handler will store anything into *range_info.
- In DsMrr_impl::choose_mrr_impl(): ha_partition will inquire partitions
about how much memory their MRR implementation needs by passing
*buffer_size=0. DS-MRR code didn't know about this (actually it used
uint for buffer size calculation and would have an under-flow).
Returning *buffer_size=0 made ha_partition assume that partitions do
not need MRR memory and pass the same buffer to each of them.
Now, this is fixed. If DS-MRR gets *buffer_size=0, it will return
the amount of buffer space needed, but not more than about
@@mrr_buffer_size.
* Fix ha_{innobase,maria,myisam}::clone. If ha_partition uses MRR on its
partitions, and partition use DS-MRR, the code will call handler->clone
with TABLE (*NOT partition*) name as an argument.
DS-MRR has no way of knowing the partition name, so the solution was
to have the ::clone() function for the affected storage engine to ignore
the name argument and get it elsewhere.
