- Scheduler is either initialized at server start or never.
Starting & stopping is now suspending & resuming.
- The scheduler has clear OO interface
- Now all calls to the scheduler are synchronous
- GLOBAL event_scheduler uses thd::sys_var_tmp (see set_var.cc)
- External API is encapsulated into class Events
- Includes fixes for all comments of Kostja's review of 19.05.2005
Starting to merge into 5.1-release (5.1.10) and push
specific to 5.0 version of the patch is motivated by the fact that a wrapper over
MYSQLLOG::write can not help in 5.0 where query's charset is embedded into event instance in the constructor.
A pattern to generate binlog for DROPped temp table in close_temporary_tables
was buggy: could not deal with a grave-accent-in-name table.
The fix exploits `append_identifier()' for quoting and duplicating accents.
Binlog lacks encoding info about DROPped temporary table.
Idea of the fix is to switch temporary to system_charset_info when a temporary table
is DROPped for binlog. Since that is the server, that automatically, but not the client, who generates the query
the binlog should be updated on the server's encoding for the coming DROP.
The `write_binlog_with_system_charset()' is introduced to replace similar problematic places in the code.
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).
Move plugin declarations after system functions have been checked
(Fixes problem with ndb_config failing becasue SHM is not declared)
Fixed some memory leaks
This performance degradation was due to the fact that some
cost evaluation code added into 4.1 in the function find_best was
not merged into the code of the function best_access_path added
together with other code for greedy optimizer.
Added a parameter to the function print_plan. The parameter contains
accumulated cost for a given partial join.
The patch does not include a special test case since this performance
degradation is hard to reproduse with a simple example.
TODO: make the function find_best use the function best_access_path
in order to remove duplication of code which might result in incomplete
merges in the future.
too many open statements". The patch adds a new global variable
@@max_prepared_stmt_count. This variable limits the total number
of prepared statements in the server. The default value of
@@max_prepared_stmt_count is 16382. 16382 small statements
(a select against 3 tables with GROUP, ORDER and LIMIT) consume
100MB of RAM. Once this limit has been reached, the server will
refuse to prepare a new statement and return ER_UNKNOWN_ERROR
(unfortunately, we can't add new errors to 4.1 without breaking 5.0). The limit is changeable after startup
and can accept any value from 0 to 1 million. In case
the new value of the limit is less than the current
statement count, no new statements can be added, while the old
still can be used. Additionally, the current count of prepared
statements is now available through a global read-only variable
@@prepared_stmt_count.
After FLUSH STATUS max_used_connections was reset to 0, and haven't
been updated while cached threads were reused, until the moment a new
thread was created.
The first suggested fix from original bug report was implemented:
a) On flushing the status, set max_used_connections to
threads_connected, not to 0.
b) Check if it is necessary to increment max_used_connections when
taking a thread from the cache as well as when creating new threads
