maria-developers team mailing list archive

[Sergei Golubchik <serg@xxxxxxxxxxx>]

Hi, Rich!

On Dec 05, Rich Prohaska wrote:
> We are debugging a crash induced by RQG in the tokudb storage engine.   The
> cause of the crash is a mismatch in assumptions about the sequence of
> storage engine API calls.
> 
> We see:
> 
> tokudb::external_lock creates a txn
> tokudb::index_init creates a cursor on a index db with the txn
> tokudb::index_read use the cursor to try to read a row, and returns an error
> tokudb_commit commits the txn (called from sql_parse.cc:4584)
> 
> tokudb::index_end tries to close the cursor and crashes since the txn has
> been committed. (called from the unit.cleanup() call at sql_parse.cc:4592)
> 
> The current tokudb software does not expect the commit to occur before
> index_end is called.  Is this assumption correct?  Since mariadb (and i
> suspect mysql) does this, it appears that the storage engine should expect
> commit before index_end.  Any comments?

You've provided too little information, so off the top of my head
I'd say that what you see is a bug and that commit should not happen in
the middle of the index scan.

What SQL statement causes it?

Regards,
Sergei