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.
the auto_increment value
This is an alternative patch that instead of allowing RECREATE TABLE
on TRUNCATE TABLE it implements reset_auto_increment that is called
after delete_all_rows.
Note: this bug was fixed by Mattias Jonsson:
Pusing this patch: http://lists.mysql.com/commits/70370
This patch fixes compilation warning, "conversion from 'time_t' to 'ulong',
possible loss of data".
The fix is to typecast time_t to ulong before assigning it to ulong.
Backported this from 6.0-bugteam tree.
This patch adds corrections to the original patch
submitted 2009-04-08 (http://lists.mysql.com/commits/71607):
- fixed that the original patch didn't work because of an
incorrect condition;
- added a test case.
Killing the insert-select statement corrupts the MyISAM table only
when the destination table is empty and when it has indexes. When
we bulk insert huge data and if the destination table is empty we
disable the indexes for fast inserts, data is then inserted and
indexes are re-enabled after bulk_insert operation
Killing the query, aborts the repair table operation during enable
indexes phase leading to table corruption.
We now truncate the table when we detect that enable indexes is
killed for bulk insert query.As we have an empty table before the
operation, we can fix by truncating the table.
A bug in the initialization of key segment information made it point
to the wrong bit, since a bit index was used when its int value
was needed. This lead to misinterpretation of bit columns
read from MyISAM record format when a NULL bit pushed them over
a byte boundary.
Fixed by using the int value of the bit instead.
single quote fails in 5.1.x
Performing fulltext prefix search (a word with truncation
operator) may cause a dead-loop.
The problem was in smarter index merge algorithm - it was writing
record reference to an incorrect memory area.
Killing insert-select statement on MyISAM corrupts the table.
Killing the insert-select statement corrupts the MyISAM table only
when the destination table is empty and when it has indexes. When
we bulk insert huge data and if the destination table is empty we
disable the indexes for fast inserts, data is then inserted and
indexes are re-enabled after bulk_insert operation
Killing the query, aborts the repair table operation during enable
indexes phase leading to table corruption.
We now truncate the table when we detect that enable indexes is
killed for bulk insert query.As we have an empty table before the
operation, we can fix by truncating the table.
Currently the memory map is being created
with a size that is greater than the size
of the underlying datafile. This can cause
varying behaviour,
e.g.
In windows the size of the datafile
is increased, while on linux it remains
the same.
This fix removes the increment margin to
the size that is used while creating the
memory map.
The conformance checker was not taking into
account, and, making concessions for acceptable
incompatibilites in tables created by
versions earlier than 4.1.
The current patch relaxes the conformance
checker to ignore differences in key_alg
and language for tables created by versions
earlier than 4.1.
The problem is that select queries executed concurrently with
a concurrent insert on a MyISAM table could be cached if the
select started after the query cache invalidation but before
the unlock of tables performed by the concurrent insert. This
race could happen because the concurrent insert was failing
to prevent cache of select queries happening at the same time.
The solution is to add a 'uncacheable' status flag to signal
that a concurrent insert is being performed on the table and
that queries executing at the same time shouldn't cache the
results.
- Remove bothersome warning messages. This change focuses on the warnings
that are covered by the ignore file: support-files/compiler_warnings.supp.
- Strings are guaranteed to be max uint in length
MyISAM did copy of key statistics incorrectly, which may cause
server crash or incorrect cardinality values. This may happen only on
platforms where size of long differs from size of pointer.
To determine number of bytes to be copied from array of ulong,
MyISAM mistakenly used sizoef(pointer) instead of sizeof(ulong).
code backported from 6.0
per-file messages:
include/my_global.h
Remove SC_MAXWIDTH. This is unused and irrelevant nowadays.
include/my_sys.h
Remove errbuf declaration and unused definitions.
mysys/my_error.c
Remove errbuf definition and move and adjust ERRMSGSIZE.
mysys/my_init.c
Declare buffer on the stack and use my_snprintf.
mysys/safemalloc.c
Use size explicitly. It's more than enough for the message at hand.
sql/sql_error.cc
Use size explicitly. It's more than enough for the message at hand.
sql/sql_parse.cc
Declare buffer on the stack. Use my_snprintf as it will result in
less stack space being used than by a system provided sprintf --
this allows us to put the buffer on the stack without causing much
trouble. Also, the use of errbuff here was not thread-safe as the
function can be entered concurrently from multiple threads.
sql/sql_table.cc
Use MYSQL_ERRMSG_SIZE. Extra space is not needed as my_snprintf will
nul terminate strings.
storage/myisam/ha_myisam.cc
Use MYSQL_ERRMSG_SIZE.
sql/share/errmsg.txt
Error message truncation in test "innodb" in embedded mode
filename in the error message can safely take up to 210 symbols.
myisam_repair_threads > 1 causes crash
Problem: parallel repair (myisam_repair_threads > 1) of a myisam
table with two or more fulltext keys that use the same parser may
lead to a server crash. ALTER TABLE ENABLE KEYS is affected as well.
Fix: properly initialize fulltext structures for parallel repair.
Note: 1. there's no deterministic test case.
2. now we call parser->init() for each fulltext key
(not for each fulltext parser used).
mmap is slower that caching indeed.
Here the problem is that mmap is used even if --myisam-use-mmap=OFF
solved by checking the flag in ha_myisam::extra() as it is called in
init_read_record()
per-file comments:
storage/myisam/ha_myisam.cc
Bug#40634 table scan temporary table is 4x slower due to mmap instead instead of caching
do nothing for HA_EXTRA_MMAP if no opt_myisam_use_mmap
partition is corrupt
The main problem was that ALTER TABLE t ANALYZE/CHECK/OPTIMIZE/REPAIR
PARTITION took another code path (over mysql_alter_table instead of
mysql_admin_table) which differs in two ways:
1) alter table opens the tables in a different way than admin tables do
resulting in returning with error before it tried the command
2) alter table does not start to send any diagnostic rows to the client
which the lower admin functions continue to use -> resulting in
assertion crash
The fix:
Remapped ALTER TABLE t ANALYZE/CHECK/OPTIMIZE/REPAIR PARTITION to use
the same code path as ANALYZE/CHECK/OPTIMIZE/REPAIR TABLE t.
Adding check in mysql_admin_table to setup the partition list for
which partitions that should be used.
Partitioned tables will still not work with
REPAIR TABLE/PARTITION USE_FRM, since that requires moving partitions
to tables, REPAIR TABLE t USE_FRM, and check that the data still
fulfills the partitioning function and then move the table back to
being a partition.
NOTE: I have removed the following functions from the handler
interface:
analyze_partitions, check_partitions, optimize_partitions,
repair_partitions
Since they are not longer needed.
THIS ALTERS THE STORAGE ENGINE API
