When converting DISTINCT to GROUP BY where the columns are from the covering
index and they are quoted twice in the SELECT list the optimizer is creating
improper processing sequence. This is because of the fact that the columns
of the covering index are not recognized as such and treated as non-index
columns.
Generally speaking duplicate columns can safely be removed from the GROUP
BY/DISTINCT list because this will not add or remove new rows in the
resulting set. Duplicates can be removed even if they are not consecutive
(as is the case for ORDER BY, where the duplicate columns can be removed
only if they are consecutive).
So we can safely transform "SELECT DISTINCT a,a FROM ... ORDER BY a" to
"SELECT a,a FROM ... GROUP BY a ORDER BY a" instead of
"SELECT a,a FROM .. GROUP BY a,a ORDER BY a". We can even transform
"SELECT DISTINCT a,b,a FROM ... ORDER BY a,b" to
"SELECT a,b,a FROM ... GROUP BY a,b ORDER BY a,b".
The fix to this bug consists of checking for duplicate columns in the SELECT
list when constructing the GROUP BY list in transforming DISTINCT to GROUP
BY and skipping the ones that are already in.
or implicitly uses stored function gives "Table not locked" error'
CREATE TABLE ... SELECT ... statement which was explicitly or implicitly
(through view) using stored function gave "Table not locked" error.
The actual bug resides in the current locking scheme of CREATE TABLE SELECT
code, which first opens and locks tables of the SELECT statement itself,
and then, having SELECT tables locked, creates the .FRM, opens the .FRM and
acquires lock on it. This scheme opens a possibility for a deadlock, which
was present and ignored since version 3.23 or earlier. This scheme also
conflicts with the invariant of the prelocking algorithm -- no table can
be open and locked while there are tables locked in prelocked mode.
The patch makes an exception for this invariant when doing CREATE TABLE ...
SELECT, thus extending the possibility of a deadlock to the prelocked mode.
We can't supply a better fix in 5.0.
Bug #19606: ssl variables are not displayed in show variables
Bug #19616: log_queries_not_using_indexes is not listed in show variables
Make basedir, datadir, tmpdir, log_queries_not_using_indexes, ssl_ca,
ssl_capath, ssl_cert, ssl_cipher, and ssl_key all available both from
SHOW VARIABLES and as @@variables.
As a side-effect of this change, log_queries_not_using_indexes can
be changed at runtime (but only globally, not per-connection).
A query with a group by and having clauses could return a wrong
result set if the having condition contained a constant conjunct
evaluated to FALSE.
It happened because the pushdown condition for table with
grouping columns lost its constant conjuncts.
Pushdown conditions are always built by the function make_cond_for_table
that ignores constant conjuncts. This is apparently not correct when
constant false conjuncts are present.
tests fail on FreeBSD.
The patch contains of the following:
- make Instance Manager, running in the daemon mode, dump
the pid of angel-process in the special file;
- default value of angel-pid-file-name is 'mysqlmanager.angel.pid';
- if ordinary (IM) pid-file-name is specified in the configuration,
angel-pid-file-name is updated according to the following
rule: extension of the basename of pid-file-name is replaced by
'.angel.pid.
For example:
- pid-file-name: /tmp/im.pid
=> angel-pid-file-name: /tmp/im.angel.pid
- pid-file-name: /tmp/im.txt
=> angel-pid-file-name: /tmp/im.angel.pid
- pid-file-name: /tmp/5.0/im
=> angel-pid-file-name: /tmp/5.0/im.angel.pid
- add support for configuration option to customize angel
pid file name;
- fix test suite to use angel pid to kill Instance Manager
by all means if something went wrong.
Background
----------
The problem is that on some OSes (FreeBSD for one) Instance
Manager does not get SIGTERM, so can not shutdown gracefully.
Test suite wasn't able to cope with it, so this leads to the
mess in test results.
The problem should be split into two:
- fix signal handling;
- fix test suite.
This patch fixes test suite so that it will be able to kill
uncooperative Instance Manager. In order to achieve this,
test suite needs to know PID of IM Angel process.
hog memory".
During each invocation of stored function or trigger some objects which
lifetime is one function call (e.g. sp_rcontext) were allocated on
arena/memroot of calling statement. This led to consumption of fixed amount
of memory for each function/trigger invocation and so statements which
involve lot of them were hogging memory. This in its return led to OOM
crashes or freezes.
This fix introduces new memroot and arena for objects which lifetime is
whole duration of function call. So all memory consumed by such objects
is freed at the end of function call.
The bug was as follows: When merge_key_fields() encounters "t.key=X OR t.key=Y" it will
try to join them into ref_or_null access via "t.key=X OR NULL". In order to make this
inference it checks if Y<=>NULL, ignoring the fact that value of Y may be not yet known.
The fix is that the check if Y<=>NULL is made only if value of Y is known (i.e. it is a
constant).
TODO: When merging to 5.0, replace used_tables() with const_item() everywhere in merge_key_fields().
after merge.
Concurrent read and update of privilege structures (like simultaneous
run of SHOW GRANTS and ADD USER) could result in server crash.
Ensure that proper locking of ACL structures is done.
No test case is provided because this bug can't be reproduced
deterministically.
