maria-discuss team mailing list archive

[Justin Swanhart <greenlion@xxxxxxxxx>]

The log for changes during the online ALTER goes in the tmp dir.  The log is applied at the end of the statement.

Sent from my iPhone

> On May 4, 2016, at 2:13 AM, Sergei Golubchik <serg@xxxxxxxxxxx> wrote:
> 
> Hi, Rhys.Campbell!
> 
>> On May 04, Rhys.Campbell@xxxxxxxxxxxx wrote:
>> Hi All,
>> 
>> For the following statement...
>> 
>> ALTER ONLINE TABLE dom_audit_event ENGINE=INNODB, ALGORITHM=INPLACE;
>> 
>> I can still see that MariaDB is still using the value of tmpdir. We
>> have this set to tmpfs on some of our servers and this causes some
>> ALTER statements on big tables to fail. It was my understanding that
>> if you specified INPLACE then the statement would fail if this was not
>> possible.
> 
> Yes, your understanding is correct.
> 
> Furthermore, copy (not inplace) ALTER does not use tmpdir, it creates a
> temporary table in the datadir, and later renames it to the actual table
> name. If the temporary table were created in tmpdir, it could not be
> renamed to a different filesystem.
> 
> So, that tmpdir usage you're seeing is not due to not-inplace alter.
> The alter isstill done inplace, and tmpdir is used for something else.
> Probaby for merge sort.
> 
> Regards,
> Sergei
> Chief Architect MariaDB
> and security@xxxxxxxxxxx
> 
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