UPDATES THE TABLE ENTRIES (formerly 55385)
BUG#11764529: MULTI UPDATE+INNODB REPORTS ER_KEY_NOT_FOUND
IF A TABLE IS UPDATED TWICE (formerly 57373)
If multiple-table update updates a row through two aliases and
the first update physically moves the row, the second update will
fail to locate the row. This results in different errors
depending on storage engine:
* MyISAM: Got error 134 from storage engine
* InnoDB: Can't find record in 'tbl'
None of these errors accurately describe the problem.
Furthermore, since MyISAM is non-transactional, the update
executed first will be performed while the second will not.
In addition, for two equal multiple-table update statements,
one could succeed and the other fail based on whether or not
the record actually moved or not. This was inconsistent.
Two update operations may physically move a row:
1) Update of a column in a clustered primary key
2) Update of a column used to calculate which partition the
row belongs to
BUG#11764529 is about case 1) above, BUG#11762751 was about case 2).
The fix for these bugs is to return with an error if multiple-table
update is about to:
a) Update a table through multiple aliases, and
b) Perform an update that may physically more the row
in at least one of these aliases
This avoids
* partial updates as described for MyISAM above,
* provides the same error message that describes the actual problem
for all SEs
* inconsistent behavior where a statement fails or succeeds based on
e.g. the partitioning algorithm of the table.
Regression introduced in bug#52455. Problem was that the
fixed function did not set the last used partition variable, resulting
in wrong partition used when storing the position of the newly
retrieved row.
Fixed by setting the last used partition in ha_partition::index_read_idx_map.
Bug#57071: EXTRACT(WEEK from date_col) cannot be allowed as partitioning function
There were functions allowed as partitioning functions
that implicit allowed cast. That could result in unacceptable
behaviour.
Solution was to check that the arguments of date and time functions
have allowed types (field and date/datetime/time depending on function).
It was possible to issue an ALTER TABLE ADD PRIMARY KEY on
an partitioned InnoDB table that failed and crashed the server.
The problem was that it succeeded to create the PK on at least
one partition, and then failed on a subsequent partition, due to
duplicate key violation. Since the partitions that already had added
the PK was not reverted all partitions was not consistent with the
table definition, which caused the crash.
The solution was to add a revert step to ha_partition::add_index()
that dropped the index for the already succeeded partitions, on failure.
Bug#57113: ha_partition::extra(ha_extra_function):
Assertion `m_extra_cache' failed
Fix for bug#55458 included DBUG_ASSERTS causing
debug builds of the server to crash on
another multi-table update.
Removed the asserts since they where wrong.
(updated after testing the patch in 5.5).
It was hard to understand what the error really meant.
The error checking in partitioning is done in several different
parts during the execution of a query which can make it
hard to return useful errors.
Added a new error for bad VALUES part in the per PARTITION clause.
Using the more verbose error that a column is not allowed in
the partitioning function instead of just that the function is
not allowed.
Problem was that the handler call ::extra(HA_EXTRA_CACHE) was cached
but the ::extra(HA_EXTRA_PREPARE_FOR_UPDATE) was not.
Solution was to also cache the other call and forward it when moving
to a new partition to scan.
myisam tables
Queries following TRUNCATE of partitioned MyISAM table
may crash server if myisam_use_mmap is true.
Internally this is MyISAM bug, but limited to partitioned
tables, because MyISAM doesn't use ::delete_all_rows()
method for TRUNCATE, but goes via table recreate instead.
MyISAM didn't properly fall back to non-mmaped I/O after
mmap() failure. Was not repeatable on linux before, likely
because (quote from man mmap):
SUSv3 specifies that mmap() should fail if length is 0.
However, in kernels before 2.6.12, mmap() succeeded in
this case: no mapping was created and the call returned
addr. Since kernel 2.6.12, mmap() fails with the error
EINVAL for this case.
Bug#40181 Made use of tdc_remove_table instead of just
setting share->version to 0 to make sure all unused table
instances go away as part of CREATE/ALTER TABLE.
ONLY_FULL_GROUP_BY
Problem was that during checking and preparation of the
partitioining function as a side effect in fix_fields
the full_group_by_flag was changed.
Solution was to set it back to its original value after
calling fix_fields.
Updated patch, to also exclude allow_sum_func from being
affected of fix_fields, as requested by reviewer.
backport for bug#44059 from mysql-pe to mysql-5.1-bugteam
Using the partition with most rows instead of first partition
to estimate the cardinality of indexes.
INSERT ... SELECT ...
Problem was that when bulk insert is used on an empty
table/partition, it disables the indexes for better
performance, but in this specific case it also tries
to read from that partition using an index, which is
not possible since it has been disabled.
Solution was to allow index reads on disabled indexes
if there are no records.
Also reverted the patch for bug#38005, since that was a workaround
in the partitioning engine instead of a fix in myisam.
when partition is reoganized.
Problem was that table->timestamp_field_type was not changed
before copying rows between partitions.
fixed by setting it to TIMESTAMP_NO_AUTO_SET as the first thing
in fast_alter_partition_table, so that all if-branches is covered.
column on partitioned table
An assertion 'ASSERT_COULUMN_MARKED_FOR_READ' is failed if the query
is executed with index containing double column on partitioned table.
The problem is that assertion expects all the fields which are read,
to be in the read_set.
In this query only the field 'a' is in the readset as the tables in
the query are joined by the field 'a' and so the assertion fails
expecting other field 'b'.
Since the function cmp() is just comparison of two parameters passed,
the assertion is not required.
Fixed by removing the assertion in the double fields comparision
function and also fixed the index initialization to do ordered
index scan with RW LOCK which ensures all the fields from a key are in
the read_set.
Note: this bug is not reproducible with other datatypes because the
assertion doesn't exist in comparision function for other
datatypes.
We disallow the partitioning of a log table. You could however
partition a table first, and then point logging to it. This is
not only against the docs, it also crashes the server.
We catch this case now.
contains ONLY_FULL_GROUP_BY
The partitioning code needs to issue a Item::fix_fields()
on the partitioning expression in order to prepare
it for being evaluated.
It does this by creating a special table and a table list
for the scope of the partitioning expression.
But when checking ONLY_FULL_GROUP_BY the
Item_field::fix_fields() was relying that there always be
cached_table set and was trying to use it to get the
select_lex of the SELECT the field's table is in.
But the cached_table was not set by the partitioning code
that creates the artificial TABLE_LIST used to resolve the
partitioning expression and this resulted in a crash.
Fixed by rectifying the following errors :
1. Item_field::fix_fields() : the code that check for
ONLY_FULL_GROUP_BY relies on having tables with
cacheable_table set. This is mostly true, the only
two exceptions being the partitioning context table
and the trigger context table.
Fixed by taking the current parsing context if no pointer
to the TABLE_LIST instance is present in the cached_table.
2. fix_fields_part_func() :
2a. The code that adds the table being created to the
scope for the partitioning expression is mostly a copy
of the add_table_to_list and friends with one exception :
it was not marking the table as cacheable (something that
normal add_table_to_list is doing). This caused the
problem in the check for ONLY_FULL_GROUP_BY in
Item_field::fix_fields() to appear.
Fixed by setting the correct members to make the table
cacheable.
The ideal structural fix for this is to use a unified
interface for adding a table to a table list
(add_table_to_list?) : noted in a TODO comment
2b. The Item::fix_fields() was called with a NULL destination
pointer. This causes uninitalized memory reads in the
overloaded ::fix_fields() function (namely
Item_field::fix_fields()) as it expects a non-zero pointer
there. Fixed by passing the source pointer similarly to how
it's done in JOIN::prepare().
