MySQL Bugs: #24333: concurrent calls to table object on columns with utf8 charse cause crash

Bug #24333	concurrent calls to table object on columns with utf8 charse cause crash
Submitted:	15 Nov 2006 11:57	Modified:	22 Dec 2006 16:03
Reporter:	Jim Dowling	Email Updates:
Status:	No Feedback	Impact on me:	None
Category:	MySQL Cluster: NDB API	Severity:	S1 (Critical)
Version:	5.1.12	OS:	Linux (Linux)
Assigned to:	Assigned Account	CPU Architecture:	Any
Tags:	cluster, table object, utf8 charset

Description:
We have encountered a SIGSEGV when multiple threads attempt to access a column with charset UTF8 using a table object.

The scenarios are:
* If multiple threads attempt to call NdbTransaction.getOperation() for a table with a UTF-8 character set 'simultaneously', we get a SIGSEGV
* If we serialise this, by having one thread call getOperation() for a table with a UTF-8 character set before any others are allowed (i.e. just after we have recovered a cluster connection) the problem goes away.
* However, we still see it in situations where the cluster_connection has been up, fails, and recovers.

It may be that it fails when there is concurrent access to the cluster to retrieve the cached table object.

How to repeat:
Only java program available for repeat.

Hi,

Looking at mysys charset code, 
it should serialize access to init_available_charsets

If you have used ndb_init (which calls my_init)
  and also call my_thread_init as first method
  as first method in a thread.

Do you use both of these calls?

Can you also expand a bit on what 
"* However, we still see it in situations where the cluster_connection has been
up, fails, and recovers." means ?

/Jonas

ok,
update to need feedback

jim,

can you updated us on what change you did (as issue now is closed)

so we know for future (and mabye even document it :-)

No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".