Re: Replication after full online init

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




On 07/01/2016 04:08 AM, William Brown wrote:
On Thu, 2016-06-30 at 14:53 -0700, Noriko Hosoi wrote:
On 06/30/2016 12:45 AM, Ludwig Krispenz wrote:
Hi William,

the reason that after  a total init the consumer does not have the 
latest state of the supplier RUV and is receiving updates based on the 
RUV at start of the total init is independent of the modrdn problem. 
When a supplier is performing a total init it is still accepting 
changes, the total init can take a while and there are scenarios where 
an entry which is already sent is updated before total init finishes. 
We cannot loose these changes.
OK...  Then, RUV needs to be created at the time when the supplier 
starts online init?

The test case would be something like this?
1. run online init on the supplier.
2. do some operation like move entries against the supplier while the 
online init is still running on the consumer.
3. do some operation which depends upon the previous operation done in 
the step 2.
4. check the consumer is healthy or not.

Isn't it a timestamp issue from which operation should be replayed after 
the total update?  Regardless of the way how to fix 48755, unless the 
step 2 operation(s) are replayed after the online init is done, the 
consumer could get broken/inconsistent?

It's not the "post init" operations I'm worried about.

It's that operations that were part of the init to the consumer are
replayed from the changelog. 

Operations that occurred after the init starts, definitely still need to
be replayed, and this makes sense.

Lets say we have:

1 - insert A
2 - insert ou=B
3 - modrdn A under ou=B
4 - insert C
xxxxxx <<-- We start to transmit the data here.
if we start the total update here, the supplier will send its RUV in the start repl request, it will be set as RUV in the consumer after total init is complete.
it skips to send the ruv entry

so mods 1-4 will not be replayed
5 - modrdn C


Once the online init is complete, the master replays the log from event
1 -> 5 to the consumer, even though it should now be up to date at
position 4.
it is

Previously we could not guarantee this because in the scenario above, A
would have sorted before ou=B, by would not be able to be applied
because the consumer hadn't seen B yet. So after the init, the consumer
would have B and C, but not A, so we had to replay 1 -> 4 to fix this
up.

So I am suggesting that when we begin the online init we set the RUV of
the consumer to match the CSN of the master at the moment we begin the
transmission of data, so that we only need to replay event 5+, rather
than 1->5+

Does that make sense? 
yes, and I think that is what it is doing now




--
389-devel mailing list
389-devel@xxxxxxxxxxxxxxxxxxxxxxx
https://lists.fedoraproject.org/admin/lists/389-devel@xxxxxxxxxxxxxxxxxxxxxxx

-- 
Red Hat GmbH, http://www.de.redhat.com/, Registered seat: Grasbrunn, 
Commercial register: Amtsgericht Muenchen, HRB 153243,
Managing Directors: Charles Cachera, Michael Cunningham, Michael O'Neill, Eric Shander
--
389-devel mailing list
389-devel@xxxxxxxxxxxxxxxxxxxxxxx
https://lists.fedoraproject.org/admin/lists/389-devel@xxxxxxxxxxxxxxxxxxxxxxx

[Index of Archives]     [Fedora Directory Announce]     [Fedora Users]     [Older Fedora Users Mail]     [Fedora Advisory Board]     [Fedora Security]     [Fedora Devel Java]     [Fedora Desktop]     [ATA RAID]     [Fedora Marketing]     [Fedora Mentors]     [Fedora Package Review]     [Fedora Art]     [Fedora Music]     [Fedora Packaging]     [CentOS]     [Fedora SELinux]     [Big List of Linux Books]     [KDE Users]     [Fedora Art]     [Fedora Docs]

  Powered by Linux