Derby Replication Issue

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Derby Replication Issue

pramavyt s


Hello,

I am trying to setup replication b/w two Derby databases. Its embedded with an application. Configuration for replication is done as per the documentation here

When the application tries to start master instance, I get to see the message. 

Lost DB connection URL= jdbc:derby:db/NMS;startMaster=true;slaveHost=10.200.10.66 + REASON= The log files on the master and slave are not in synch for replicated database 'db/NMS'. The master log instant is 1:200335, whereas the slave log instant is 1:196097. This is fatal for replication - replication will be stopped.:


There is some exchange happening on the replication port b/w master & slave. But master quits with the message. Per the documentation,before starting master, the database is copied to the slave location. And no transaction happens in master after that. What does the message ( mismatch in log instance) mean? What could I be missing?



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RE: Derby Replication Issue

Michael Remijan

Embedded database can only be accessed by the application, nothing external. Seems to me like replication between embedded databases wouldn’t work.

 

From: pramavyt s <[hidden email]>
Sent: Thursday, August 27, 2020 8:58 AM
To: [hidden email]
Subject: Derby Replication Issue

 

 

Hello,

I am trying to setup replication b/w two Derby databases. Its embedded with an application. Configuration for replication is done as per the documentation here

When the application tries to start master instance, I get to see the message. 

Lost DB connection URL= jdbc:derby:db/NMS;startMaster=true;slaveHost=10.200.10.66 + REASON= The log files on the master and slave are not in synch for replicated database 'db/NMS'. The master log instant is 1:200335, whereas the slave log instant is 1:196097. This is fatal for replication - replication will be stopped.:

 

There is some exchange happening on the replication port b/w master & slave. But master quits with the message. Per the documentation,before starting master, the database is copied to the slave location. And no transaction happens in master after that. What does the message ( mismatch in log instance) mean? What could I be missing?

 

 

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Re: Derby Replication Issue

pramavyt s
@ Michael, thanks for your feedback. It looks like replication is supported in embedded mode as well .

From the documentation , we have the following reference:

"You can perform replication on a database that runs in either embedded mode or Network Server mode."

 

On Thu, Aug 27, 2020 at 11:20 PM Michael Remijan <[hidden email]> wrote:

Embedded database can only be accessed by the application, nothing external. Seems to me like replication between embedded databases wouldn’t work.

 

From: pramavyt s <[hidden email]>
Sent: Thursday, August 27, 2020 8:58 AM
To: [hidden email]
Subject: Derby Replication Issue

 

 

Hello,

I am trying to setup replication b/w two Derby databases. Its embedded with an application. Configuration for replication is done as per the documentation here

When the application tries to start master instance, I get to see the message. 

Lost DB connection URL= jdbc:derby:db/NMS;startMaster=true;slaveHost=10.200.10.66 + REASON= The log files on the master and slave are not in synch for replicated database 'db/NMS'. The master log instant is 1:200335, whereas the slave log instant is 1:196097. This is fatal for replication - replication will be stopped.:

 

There is some exchange happening on the replication port b/w master & slave. But master quits with the message. Per the documentation,before starting master, the database is copied to the slave location. And no transaction happens in master after that. What does the message ( mismatch in log instance) mean? What could I be missing?

 

 

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Re: Derby Replication Issue

Oskar Zinger
You have to make sure that you shutdown the DB (or freeze), copy it over to slave, start master and start slave. And if you shutdown the DB, you must make sure that no calls are made to the DB that will start it up.

Regards,
Oskar

On Aug 27, 2020, at 2:21 PM, pramavyt s <[hidden email]> wrote:

@ Michael, thanks for your feedback. It looks like replication is supported in embedded mode as well .

From the documentation , we have the following reference:

"You can perform replication on a database that runs in either embedded mode or Network Server mode."

 

On Thu, Aug 27, 2020 at 11:20 PM Michael Remijan <[hidden email]> wrote:

Embedded database can only be accessed by the application, nothing external. Seems to me like replication between embedded databases wouldn’t work.

 

From: pramavyt s <[hidden email]>
Sent: Thursday, August 27, 2020 8:58 AM
To: [hidden email]
Subject: Derby Replication Issue

 

 

Hello,

I am trying to setup replication b/w two Derby databases. Its embedded with an application. Configuration for replication is done as per the documentation here

When the application tries to start master instance, I get to see the message. 

Lost DB connection URL= jdbc:derby:db/NMS;startMaster=true;slaveHost=10.200.10.66 + REASON= The log files on the master and slave are not in synch for replicated database 'db/NMS'. The master log instant is 1:200335, whereas the slave log instant is 1:196097. This is fatal for replication - replication will be stopped.:

 

There is some exchange happening on the replication port b/w master & slave. But master quits with the message. Per the documentation,before starting master, the database is copied to the slave location. And no transaction happens in master after that. What does the message ( mismatch in log instance) mean? What could I be missing?