ha_spider::field_exchange() returns NULL and that results in a crash
or a assertion failure in spider_db_open_item_ident().
In the first place, there seems to be no need to call field_exchange()
for printing an identity (column name with alias). Thus, we simply
remove the call.
The partition storage engine ignores return (error) values of
handler::info(). As a result, a query that should be aborted is
not aborted and then the server violates the assertion.
Item_func_xor and Item_cond are both derived class of Item_bool_func.
Spider converts *Item_func_xor to *Item_cond and then calls the member
function argument_list(), which Item_func_xor does not implement.
The Spider mixes the comma join with other join types, and thus
ERROR 1054 occurs. This is well-known issue caused by the higher
precedence of JOIN over the comma (,).
We can fix the problem simply by using JOINs instead of commas.
The heap-use-after-free is caused by the following mechanism:
* In the execution of FLUSH TABLE WITH READ LOCK, the function
spider_free_trx_conn() is called and the connections held by
SPIDER_TRX::trx_conn_hash are freed.
* Then, an instance of ha_spider maintains the freed connections
because they are also referenced from ha_spider::conns.
The ha_spider instance is kept in a lock structure until the
corresponding table is unlocked.
* Spider accesses ha_spider::conns on the implicit UNLOCK TABLE
issued by BEGIN.
In the first place, when the connections have been freed, it means
that there are really no remote table locked by Spider.
Thus, there is no need for Spider to access ha_spider::cons on the
implicit UNLOCK TABLE.
We can fix the bug by removing the above mentioned access to
ha_spider::conns. We also modified spider_free_trx_conn() so that it
frees the connections only when no table is locked to reduce the
chance of another heap-use-after-free on ha_spider::conns.
Spider supports (or at least allows) INSERT DELAYED but the
documentation does not specify spider as a storage engine that supports
"INSERT DELAYED".
Also, although not mentioned in the documentation, "INSERT DELAYED" is
not intended to be executed inside a transaction, as can be seen from
the list of supported storage engines.
The current implementation allows executing a delayed insert on a
remote transactional table and this breaks the consistency ensured by
the transaction.
We too remove "internal_delayed", one of the Spider table parameters.
Documentation says,
> Whether to transmit existence of delay to remote servers when
> executing an INSERT DELAYED statement on local server.
This table parameter is only used for "INSERT DELAYED".
Reviewed by: Nayuta Yanagisawa
When the variable, spider_semi_table_lock, is 1, Spider sends
LOCK TABLES before each SQL execution. The feature is for
non-transactional remote tables and adds some overhead to query
executions.
We change the default value of the plugin variable to 0 and then
deprecate the variable because it is rare to use non-transactional
engines these days and the variable complicates the code.
The variable, spider_semi_table_lock_connection, should be too
deprecated because it is for tweaking the semi-table locking.
Deprecate the high availability feature of Spider as the feature is
beyond the scope of the federated storage engine and it complicates
the implementation of Spider.
and failing spider partition test.
With some small datatype changes to the Linux/Solaris my_gethwaddr implementation
the hardware address of AIX can be returned. This is an important aspect
in Spider (and UUID).
Spider test change reviewed by Nayuta Yanagisawa.
my_gethwaddr review by Monty in #2081
