DROP USER looks for sessions by the do-be-dropped user and if found:
* fails with ER_CANNOT_USER in Oracle mode
* continues with ER_ACTIVE_CONNECTIONS_FOR_USER_TO_DROP warning otherwise
Every user being dropped is marked with flag that disallow establishing
a new connections on behalf this user.
Remove one of the major sources of race condiitons in mariadb-test.
Normally, mariadb_close() sends COM_QUIT to the server and immediately
disconnects. In mariadb-test it means the test can switch to another
connection and sends queries to the server before the server even
started parsing the COM_QUIT packet and these queries can see the
connection as fully active, as it didn't reach dispatch_command yet.
This is a major source of instability in tests and many - but not all,
still less than a half - tests employ workarounds. The correct one
is a pair count_sessions.inc/wait_until_count_sessions.inc.
Also very popular was wait_until_disconnected.inc, which was completely
useless, because it verifies that the connection is closed, and after
disconnect it always is, it didn't verify whether the server processed
COM_QUIT. Sadly the placebo was as widely used as the real thing.
Let's fix this by making mariadb-test `disconnect` command _to wait_ for
the server to confirm. This makes almost all workarounds redundant.
In some cases count_sessions.inc/wait_until_count_sessions.inc is still
needed, though, as only `disconnect` command is changed:
* after external tools, like `exec $MYSQL`
* after failed `connect` command
* replication, after `STOP SLAVE`
* Federated/CONNECT/SPIDER/etc after `DROP TABLE`
and also in some XA tests, because an XA transaction is dissociated from
the THD very late, after the server has closed the client connection.
Collateral cleanups: fix comments, remove some redundant statements:
* DROP IF EXISTS if nothing is known to exist
* DROP table/view before DROP DATABASE
* REVOKE privileges before DROP USER
etc
The main purpose of this allow one to use the --read-only
option to ensure that no one can issue a query that can
block replication.
The --read-only option can now take 4 different values:
0 No read only (as before).
1 Blocks changes for users without the 'READ ONLY ADMIN'
privilege (as before).
2 Blocks in addition LOCK TABLES and SELECT IN SHARE MODE
for not 'READ ONLY ADMIN' users.
3 Blocks in addition 'READ_ONLY_ADMIN' users for all the
previous statements.
read_only is changed to an enum and one can use the following
names for the lock levels:
OFF, ON, NO_LOCK, NO_LOCK_NO_ADMIN
Too keep things compatible with older versions config files, one can
still use values FALSE and TRUE, which are mapped to OFF and ON.
The main visible changes are:
- 'show variables like "read_only"' now returns a string
instead of a number.
- Error messages related to read_only violations now contains
the current value off readonly.
Other things:
- is_read_only_ctx() renamed to check_read_only_with_error()
- Moved TL_READ_SKIP_LOCKED to it's logical place
Reviewed by: Sergei Golubchik <serg@mariadb.org>
fix test cases like
... prepare the test, create a table or a user
create event ... on schedule every 1 second ... do something ...
... verify that something was done
... cleanup drop event, table or user
here the event scheduler can manage to start the worker for the
second execution of the event, then cleanup happens
and the worker realizes that it cannot change the security context
(as the user is dropped) or cannot insert (as the table is dropped).
followup for 279b0db8c6 (that removed suppression of /Event Schedule/)
* removed universal suppression of everything "Event Schedule" everywhere
* added suppressions in tests as needed
* moved events test to the events suite
* renamed -master.opt -> .opt
* added standard test header
* verified in the test that the error, indeed, was written into the log
* removed useless suppressions
* removed ER_EVENTS_NO_ACL, replaced with ER_OPTION_PREVENTS_STATEMENT
* fixed error message to say exactly what option disabled event scheduler
instead of "this or that or that, you figure it out"
* also fixed old message for SET event_scheduler=
(it was also non-translatable)
* changed to use sql_print_error() when an error is not sent to the user
* removed duplicate hard-coded error message
