Spider waits until the server initialization has been completed
(i.e., mysqld_server_started has been set to 1) before creating the
Spider system tables. Spider also wait until the system tables have
been created before instantiating ha_spider.
These waits leads to dead lock when a non-system Spider table is
created by --in-file. This is because queries passed by --in-file
are executed during the server initialization and creating the
non-system Spider table causes an instantiation of ha_spider.
In the first place, there seems to be no need for Spider to do such
a synchronization. Thus, we simply remove the synchronization.
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.
Delete the deprecated variable, spider_use_handler and related code.
Spider now does not supports accessing data nodes via handler
statements. Thus, the notion of SQL kinds are no longer useful.
We too discard it.
Deprecate the server variable spider_internal_offset and the corresponding
table parameters "ios" and "internal_offset".
We believe this variable is not much use to users, therefore decided to
deprecate it.
Reviewed-by: Nayuta Yanagisawa <nayuta.yanagisawa@hey.com>
The variables, spider_crd_mode and spider_sts_mode, specify the
ways to fetch statistics from data nodes.
Using the SHOW command seems to work for any cases. Thus, we deprecate
the variables.
The variable spider_internal_limit is for specifying the number of
records acquired by Spider from each remote server.
There seems not to be much use of the variable. Thus, we deprecate it
and the corresponding table options.
Reviewed-by: Nayuta Yanagisawa <nayuta.yanagisawa@hey.com>
Creating a temporary table with Spider is non-sense because a Spider
table cannot hold any physical data and it requires an additional
effort to manage even if it is configured correctly.
Set HTON_TEMPORARY_NOT_SUPPORTED to spider_hton->flags.
Reviewed-by: nayuta.yanagisawa@hey.com
Co-authored-by: d8sk4ueun@gmail.com
"#ifdef WITH_PARTITION_STORAGE_ENGINE ... #endif" appears frequently
in the Spider code base. However, there is no need to maintain such
ifdefs because Spider is disabled if the partitioning engine is disabled.
