DISABLE AND ENABLED DURING DDL OPERATION
PROBLEM: Same thread trying to acquire the same mutex
second time leads to hang/server crash.
While [un]installing audit_log plugin
a thread acquires the LOCK_plugin mutex
and after successful initialization tries
to write in mysql.plugin table. It holds
this mutex for a long time. If some how
plugin table is corrupted then a write to
plugin table will throw an error, thread try
to log this error in the audit_log plugin,
doing so it tries to acquire the mutex
again and results is server hang/crash.
SOLUTION: Releasing the LOCK_plugin mutex before
writing in mysql.plugin table. We dont
need to hold this mutex as thread already
acquired a TL_WRITE lock on mysql.plugin
table.
This patch adds a new client utility that enables or disables plugin
features. The utility disables or enables a plugin using values (name,
soname, and symbols) provided via a configuration file by the same name.
For example, to ENABLE the daemon_example plugin, the utility will read
the daemon_example.ini configuration file and use the values contained to
enable or disable the plugin.
Put descriptions of plugins into a separate file read by MTR
MTR itself has generalised code to read this and set env. variables
Removed the *SO variables, updated some tests accordingly
New commit: added optional list of plugin names for _LOAD variable
Also made changes for the new AUTH_* plugins
