is it possible to recover from 3 master node about redis cluster - redis

Today I read the redis cluster reslect the master node procedure. They told that at least half of the master pass will select the new master node. For example, I have a 3 master and each master have 2 salve, when one of the master fail, the slave node will request to become the new master node, but now there only have 2 master node, sometime it may cause never select the master node successs? how to avoid one master select slave a, one master select slave b?

Related

Subscription has received a request for an abort shutdown

I have a subscription with DB2 for i (as400) as source and Kafka as target (11.4.0.2). The replication method is REFRESH.
There was a table in the subscription, which was running well.
But after I delete it and add it to another new subscription (with same source and target, also REFRESH), it cannot be replicated. The replication end with following message:
Subscription XXX has received a request for an abort shutdown. There are no other error messages. The table mapping (flag for refresh already) seems being ignored by CDC.
From the log, it returns:
Received normal shutdown request number 9 with reason OTHER_ENGINE_COMPLETE
I have no idea what is happening as there are no obvious hints from logs.
I tried (1) recreate table mapping and (2) update table definitions, but not working.
Other tables in the subscription can be replicated.
Please check after you delete table mapping from earlier subscription, is it still showing by checking 'replication tables' in MC (select datastore -> replication tables) select and remove and remap in new subscription.
Thanks
Sudarshan K

Changing number of backup from x to y in ignite cluster

I have a ignite cluster running with 8 nodes.
I created one table
CREATE TABLE Sample(....) WITH "template=partitioned,backups=1"
and it is having 300 Millon entries (cache: "SampleCache")
Now I want to change back up to 0. How can I do this?
Documentation of ALTER doesn't specify anything related to this.
I want to avoid dropping table and creating again.
I'm afraid there's no support for changing cache configuration after it is started. This means you will have to drop table and create another one.

Merge replication error the schema script could not be propagated to the subscriber SQL Server 2008

I am with replication so after trying for 1 month I am able to initialize publisher on remote system and subscriber on my local system. When I run job at subscriber end I get an error
the schema script AccountNotic1234.sch could not be propagated to the subscriber
Somewhere I read this error happens when tables are connected using foreign keys and you missing primary table but I am synchronizing all tables. So it can not be the issue.
When I run the subscription I get error for 3 tables in order not on 1st and 2nd don't know why?
What can be the possible reasons for this?

Database replication stops if data is changed on the subscriber

Should the SQL database replication stop if i delete one record in a replicated table on the subscriber end?
I remember having a replication running where the delete on subscriber would be overwritten from publisher effectively preventing you from deleting the data.
But in our new configuration it crashed the replication when we deleted one record.
It depends. If you deleted a row at the subscriber that is subsequently updated at the publisher, replication will break when the update is propagated. Why is this? If you look at how the command is replicated, it calls a stored procedure with the PK column(s), a bit mask of what columns changed, and then the list of new values for columns that changed (I'm glossing over some detail, but you can look for yourself in the subscriber database; the procedures are all there and pretty accessible). Because it doesn't re-replicate the whole row again, if it doesn't find the row indicated by the PK, replication assumes (correctly) that the subscriber is no longer in sync with the publisher and stops. As far as I know, replication has never worked in the way you describe.
TL;DR: you should treat the subscriber database(s) as read-only except by the replication process itself.

Replication related issue,

Replication related issue,
I am explaining my architecture .
I have created , its transactinal replication process
2 Publisher on table vendors script I have given below,
A Distributor
2 Subscribers
Data replication set up is like this as :
Table VENDORS gets replicated from 2-publishers to 2-subcribers via-Distributor.
While replication, ERROR issued in Distributor database as :
Here, What must happen is
Pub1 (creates pubs table vendors) –> inserts (vendors) data to Distributor. -> pull by subscribers
What is happening now for me is ,
Pub1 (creates pubs table vendors-done) -> Throws error at distributor database as
Replication-Replication Distribution Subsystem: agent abc-serv1\PRD01-star-star Billing-PROD-VREPL1\REPL01-25 failed.
Violation of PRIMARY KEY constraint 'PK_vendors'. Cannot insert duplicate key in object 'dbo.vendors'.
Error is issued while operation is done between Publishers to Distributor.
The Primary Key at the Publisher has to be maintained at the Subscriber when using Transactional Replication. It sounds as though a record with the given key value already exists at the Subscriber.
From your topology description you have two separate Publications.
So:
Subscriber 1 receives Publication 1
Subscriber 2 receives Publication 2
Is there any crossover i.e. can Subscriber 2 also receives Publication 1. If so then you will encounter Primary Key conflicts unless you manage the key ranges on both Publishers or use an alternative Replication technology, such as Merge Replication.