The problem was that some facilities (like CONVERT_TZ() function or
server HELP statement) may require implicit access to some tables in
'mysql' database. This access was done by ordinary means of adding
such tables to the list of tables the query is going to open.
However, if we issued LOCK TABLES before that, we would get "table
was not locked" error trying to open such implicit tables.
The solution is to treat certain tables as MySQL system tables, like
we already do for mysql.proc. Such tables may be opened for reading
at any moment regardless of any locks in effect. The cost of this is
that system table may be locked for writing only together with other
system tables, it is disallowed to lock system tables for writing and
have any other lock on any other table.
After this patch the following tables are treated as MySQL system
tables:
mysql.help_category
mysql.help_keyword
mysql.help_relation
mysql.help_topic
mysql.proc (it already was)
mysql.time_zone
mysql.time_zone_leap_second
mysql.time_zone_name
mysql.time_zone_transition
mysql.time_zone_transition_type
These tables are now opened with open_system_tables_for_read() and
closed with close_system_tables(), or one table may be opened with
open_system_table_for_update() and closed with close_thread_tables()
(the latter is used for mysql.proc table, which is updated as part of
normal MySQL server operation). These functions may be used when
some tables were opened and locked already.
NOTE: online update of time zone tables is not possible during
replication, because there's no time zone cache flush neither on LOCK
TABLES, nor on FLUSH TABLES, so the master may serve stale time zone
data from cache, while on slave updated data will be loaded from the
time zone tables.
index_read(), index_read_idx(), index_read_last(), and
records_in_range() - instead of 'uint keylen' argument take
'ulonglong keypart_map', a bitmap showing which keyparts are
present in the key value.
Fallback method is provided for handlers that are lagging behind.
Moved .progress files into the log directory
Moved 'cluster' database tables into the MySQL database, to not have 'cluster' beeing a reserved database name
Fixed bug where mysqld got a core dump when trying to use a table created by MySQL 3.23
Fixed some compiler warnings
Fixed small memory leak in libmysql
Note that this doesn't changeset doesn't include the new mysqldump.c code required to run some tests. This will be added when I merge 5.0 to 5.1
