>
> Erick, one last question: Is there a quick and easy way to extract the
> date from a time UUID?
>
Yeah, just use any online converters on the web. Cheers!
>
> Any possibility that you "merged" two clusters together?
Ooohh...I think that's the missing piece of this puzzle! A couple weeks
earlier, prior to the problem described in this thread, we did
inadvertently merge two clusters together. We merged the original 'dc1'
cluster with an entirely
I agree with Jeff that this isn't related to ALTER TABLE. FWIW, the
original table was created in 2017 but a new version got created on August
5:
- 20739eb0-d92e-11e6-b42f-e7eb6f21c481 - Friday, January 13, 2017 at
1:18:01 GMT
- 8ad72660-f629-11eb-a217-e1a09d8bc60c - Thursday, August 5,
Jeff,
Ahh...I see. That makes sense. I'll add this to the list of things to check
before making a schema change.
Thanks so much for taking the time to walk me through this. Really
appreciate all of your help!
On Fri, Oct 15, 2021 at 3:52 PM Jeff Jirsa wrote:
> Consistency doesnt matter for
Consistency doesnt matter for schema.
For every host: " select id from system_schema tables WHERE keyspace_name=?
and table_name=?" (
https://github.com/apache/cassandra/blob/cassandra-3.11/src/java/org/apache/cassandra/schema/SchemaKeyspace.java#L144
)
Then, compare that to the
So, if I were to do `CONSISTENCY ALL; select *` from each of the
system_schema tables, then on-disk and in-memory should be in sync?
On Fri, Oct 15, 2021 at 3:38 PM Jeff Jirsa wrote:
> Heap dumps + filesystem inspection + SELECT from schema tables.
>
>
> On Fri, Oct 15, 2021 at 3:28 PM Tom
Heap dumps + filesystem inspection + SELECT from schema tables.
On Fri, Oct 15, 2021 at 3:28 PM Tom Offermann
wrote:
> Interesting!
>
> Is there a way to determine if the on-disk schema and the in-memory schema
> are in sync? Is there a way to force them to sync? If so, would it help to
>
Interesting!
Is there a way to determine if the on-disk schema and the in-memory schema
are in sync? Is there a way to force them to sync? If so, would it help to
force a sync before running an `ALTER KEYSPACE` schema change?
On Fri, Oct 15, 2021 at 3:08 PM Jeff Jirsa wrote:
> I would not
I would not expect an ALTER KEYSPACE to introduce a divergent CFID, that
usually happens during a CREATE TABLE. With no other evidence or ability to
debug, I would guess that the CFIDs diverged previously, but due to the
race(s) I described, the on-disk schema and the in-memory schema differed,
Jeff,
Thanks for describing the race condition.
I understand that performing concurrent schema changes is dangerous, and
that running an `ALTER KEYSPACE` on one node, and then running another
`ALTER KEYSPACE` on a different node, before the first has fully propagated
throughout the cluster, can
Vytenis,
I ran the `ALTER KEYSPACE` command on one of the original `dc1` nodes.
Should it make any difference? My understanding was that it could be run
from any node in either datacenter. But, if there's a reason to prefer
running it on a new datacenter node, I'm happy to do it that way.
--Tom
Stefan,
Yes, this is probably one of many good reasons to upgrade!
Upgrading to Cassandra 4.0 is definitely on our roadmap, but we're hoping
to do these migrations first before we upgrade.
However, if we keep running into this problem, we may have to rethink that
ordering.
--Tom
On Wed, Oct
I've described this race a few times on the list. It is very very dangerous
to do concurrent table creation in cassandra with non-determistic CFIDs.
I'll try to describe it quickly right now:
- Imagine you have 3 hosts, A B and C
You connect to A and issue a "CREATE TABLE ... IF NOT EXISTS".
A
You ran the `alter keyspace` command on the original dc1 nodes or the new
dc2 nodes?
On Wed, Oct 13, 2021 at 8:15 AM Stefan Miklosovic <
stefan.mikloso...@instaclustr.com> wrote:
> Hi Tom,
>
> while I am not completely sure what might cause your issue, I just
> want to highlight that schema
Hi Tom,
while I am not completely sure what might cause your issue, I just
want to highlight that schema agreements were overhauled in 4.0 (1) a
lot so that may be somehow related to what that ticket was trying to
fix.
Regards
(1) https://issues.apache.org/jira/browse/CASSANDRA-15158
On Fri, 1
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