Invaldating a subset of a sufficiently large query cache can take a long time.
During this time the server is efficiently frozen and no other operation can
be executed. This patch addresses this problem by moving the locks which cause
the freezing and also by temporarily disable the query cache while the
invalidation takes place.
profiling. Also,
Bug#26938: profiling client hang if used before enabled
In the SHOW command, not sending header data because we had no
rows to send was a protocol violation. Porting the SHOW PROFILE
command to use the Information Schema table avoids that problem.
This bug may manifest itself not only with the queries for which
the index-merge access method is chosen. It also may display
itself for queries with DISTINCT.
The bug was in how the Unique::get method used the merge_buffers
function. To compare elements in the the queue employed by
merge_buffers() it must use the buffpek_compare function rather
than the function for binary comparison.
NDB util thread calls mysql_parse internally with plain old c strings (7bit ascii) to create tables (e.g. mysql.ndb_schema). With mysqld default charset set to a multibyte one (e.g. ucs2) mysql_parse would try to interpret the 7bit string as UCS2 and promptly explode in a heap.
Solution is to set the util thread to be using utf8 charset.
Index: ndb-work/sql/ha_ndbcluster.cc
===================================================================
previous correction didn't. make sure "tail" is fixed up
when filling cache several times; rework formulae.
---
Merge sin.intern.azundris.com:/home/tnurnberg/22540/50-22540
into sin.intern.azundris.com:/home/tnurnberg/22540/51-22540
When a UNION statement forced conversion of an UTF8
charset value to a binary charset value, the byte
length of the result values was truncated to the
CHAR_LENGTH of the original UTF8 value.
In Automake,
mysqld_LDADD = libndb.la
only adds libndb to the link command for mysqld,
but does not declare a dependency.
Added libndb.la to mysqld_DEPENDENCIES
This fix a build race condition that currently
breaks make -J builds, and also enforce a re-link
of mysqld when libndb.la changes.
Problem: "Under high load, the slave registering to the master can timeout
during the COM_REGISTER_SLAVE execution. This causes an error, which
prevents the slave from connecting at all."
Fix: Do not abort immediately, but retry registering on master.
1. Fix ddl_i18n_koi8r, ddl_i18n_utf8: explicitly specify character-sets
directory for mysqldump;
2. Fix crash in mysqldump if collation is not found;
3. Use proper way to compare character set names.
query / no aggregate of subquery
The optimizer counts the aggregate functions that
appear as top level expressions (in all_fields) in
the current subquery. Later it makes a list of these
that it uses to actually execute the aggregates in
end_send_group().
That count is used in several places as a flag whether
there are aggregates functions.
While collecting the above info it must not consider
aggregates that are not aggregated in the current
context. It must treat them as normal expressions
instead. Not doing that leads to incorrect data about
the query, e.g. running a query that actually has no
aggregate functions as if it has some (and hence is
expected to return only one row).
Fixed by ignoring the aggregates that are not aggregated
in the current context.
One other smaller omission discovered and fixed in the
process : the place of aggregation was not calculated for
user defined functions. Fixed by calling
Item_sum::init_sum_func_check() and
Item_sum::check_sum_func() as it's done for the rest of
the aggregate functions.
"Federared Transactions Failure"
Bug occurs when the user performs an operation which inserts more than
one row into the federated table and the federated table references a
remote table stored within a transactional storage engine. When the
insert operation for any one row in the statement fails due to
constraint violation, the federated engine is unable to perform
statement rollback and so the remote table contains a partial commit.
The user would expect a statement to perform the same so a statement
rollback is expected.
This bug was fixed by implementing bulk-insert handling into the
federated storage engine. This will relieve the bug for most common
situations by enabling the generation of a multi-row insert into the
remote table and thus permitting the remote table to perform
statement rollback when neccessary.
The multi-row insert is limited to the maximum packet size between
servers and should the size overflow, more than one insert statement
will be sent and this bug will reappear. Multi-row insert is disabled
when an "INSERT...ON DUPLICATE KEY UPDATE" is being performed.
The bulk-insert handling will offer a significant performance boost
when inserting a large number of small rows.
This patch builds on Bug29019 and Bug25511
"Federated INSERT failures"
Federated does not correctly handle "INSERT...ON DUPLICATE KEY UPDATE"
However, implementing such support is not reasonably possible without
increasing complexity of the storage engine: checking that constraints
on remote server match local server and parsing error messages.
This patch causes 'ON DUPLICATE KEY' to fail with ER_DUP_KEY message
if a conflict occurs and not to fail silently.
- BUG#11986: Stored routines and triggers can fail if the code
has a non-ascii symbol
- BUG#16291: mysqldump corrupts string-constants with non-ascii-chars
- BUG#19443: INFORMATION_SCHEMA does not support charsets properly
- BUG#21249: Character set of SP-var can be ignored
- BUG#25212: Character set of string constant is ignored (stored routines)
- BUG#25221: Character set of string constant is ignored (triggers)
There were a few general problems that caused these bugs:
1. Character set information of the original (definition) query for views,
triggers, stored routines and events was lost.
2. mysqldump output query in client character set, which can be
inappropriate to encode definition-query.
3. INFORMATION_SCHEMA used strings with mixed encodings to display object
definition;
1. No query-definition-character set.
In order to compile query into execution code, some extra data (such as
environment variables or the database character set) is used. The problem
here was that this context was not preserved. So, on the next load it can
differ from the original one, thus the result will be different.
The context contains the following data:
- client character set;
- connection collation (character set and collation);
- collation of the owner database;
The fix is to store this context and use it each time we parse (compile)
and execute the object (stored routine, trigger, ...).
2. Wrong mysqldump-output.
The original query can contain several encodings (by means of character set
introducers). The problem here was that we tried to convert original query
to the mysqldump-client character set.
Moreover, we stored queries in different character sets for different
objects (views, for one, used UTF8, triggers used original character set).
The solution is
- to store definition queries in the original character set;
- to change SHOW CREATE statement to output definition query in the
binary character set (i.e. without any conversion);
- introduce SHOW CREATE TRIGGER statement;
- to dump special statements to switch the context to the original one
before dumping and restore it afterwards.
Note, in order to preserve the database collation at the creation time,
additional ALTER DATABASE might be used (to temporary switch the database
collation back to the original value). In this case, ALTER DATABASE
privilege will be required. This is a backward-incompatible change.
3. INFORMATION_SCHEMA showed non-UTF8 strings
The fix is to generate UTF8-query during the parsing, store it in the object
and show it in the INFORMATION_SCHEMA.
Basically, the idea is to create a copy of the original query convert it to
UTF8. Character set introducers are removed and all text literals are
converted to UTF8.
This UTF8 query is intended to provide user-readable output. It must not be
used to recreate the object. Specialized SHOW CREATE statements should be
used for this.
The reason for this limitation is the following: the original query can
contain symbols from several character sets (by means of character set
introducers).
Example:
- original query:
CREATE VIEW v1 AS SELECT _cp1251 'Hello' AS c1;
- UTF8 query (for INFORMATION_SCHEMA):
CREATE VIEW v1 AS SELECT 'Hello' AS c1;
