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.
Replaced abs_top_srcdir with top_srcdir, not sure it's an
improvement but at least it's known that abs_top_srcdir
in cases have a problem and this is a more common variable
to use for the same purpose.
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
The problem was that symlink.test failed due to debug assertions or
due to errors emitted for wrong statements (in non-debug builds)
if 6.0 version of server was run with --thread-handling=pool-of-threads
option.
The above problems were caused by that on the one hand code mi_create()
which handles case when error is returned relies on my_errno being set
to appropriate non-0 value, but on the other it has not done this
in case when error was emitted due to discovery that share for table
which we are going to create is already present in the list of open
shares. Running server with pool-of-threads option just exposed this
bug since in this scheduler mode my_errno is reset to 0 when connection
(THD) is reattached to the "real" thread.
This fix ensures that code in mi_create() properly sets my_errno in
the case described above.
Since original reason that caused this bug to be exposed in 6.0 tree
might also under very special conditions lead to incorrect behavior
of earlier versions of server (i.e. to errors emitted for wrong
statements) this patch is also being pushed into 5.1 tree.
No test case is present as this code is already covered by a test
case + pushbuild options combination in 6.0.
after few delete statements
Problem: changing a file size might require that it must be
unmapped beforehand.
Fix: unmap the file before changing its size.
value" error even though the value was correct): a C function in my_getopt.c
was taking bool* in parameter and was called from C++ sql_plugin.cc,
but on some Mac OS X sizeof(bool) is 1 in C and 4 in C++, giving funny
mismatches. Fixed, all other occurences of bool in C are removed, future
ones are blocked by a "C-bool-catcher" in my_global.h (use my_bool).
A table with BLOB/TEXT prefix key part, created with version 4.1,
could not be opened by a 5.1 server.
The routine check at table open, if the frm file matches the MyISAM
table, was too picky regarding old and new implementation of such
keys.
Added relaxed check for blob prefix key part.
No test case. It requires to create a table in 4.1 and open it in
5.1.
myisamchk did always show Character set: latin1_swedish_ci (8),
regardless what DEFAULT CHARSET the table had.
When the server created a MyISAM table, it did not copy the
characterset number into the MyISAM create info structure.
Added assignment of charset number to MI_CREATE_INFO.
and a char-field > 128 exists
CHECK TABLE (non-QUICK) and any form of repair table did wrongly rate
records as corrupted under the following conditions:
1. The table has dynamic row format and
2. it has a CHAR like column > 127 bytes (but not VARCHAR)
(for multi-byte character sets this could be less than 127
characters) and
3. it has records with > 127 bytes significant length in that column
(a byte beyond byte position 127 must be non-space).
Affected were the statements CHECK TABLE, REPAIR TABLE, OPTIMIZE TABLE,
ALTER TABLE. CHECK TABLE reported and marked the table as crashed if any
record was present that fulfilled condition 3. The other statements
deleted these records.
The problem was a signed/unsigned compare in MyISAM code. A
char to uchar change became necessary after the big byte to uchar
change.
