"Unexpected error has occurred: Disabling SyncSnapshotTask" error logged

The architecture of EON blockchain is node-centric. Nodes (or peers) perform a variety of tasks including the validation of transactions earning rewards. To start, one needs to deploy an EON node (also called a masternode). See Requirements for deploying a masternode for hard- and software requirements, and Deploying an EON node (peer) on a Linux based host for the step-by-step guide.

When deployed and running, an EON node may encounter various issues. The issues are logged in the docker log.

To access the log, execute the following 2 commands:

Click here to expand...

1. Find a container, from where you want to extract a log from:

docker ps [OPTIONS]

where 'Options':
-a, --all Show all containers (default shows just running)
-f, --filter filter Filter output based on conditions provided
--format string Pretty-print containers using a Go template
--help Print usage
-n, --last int Show n last created containers (includes all states) (default -1)
-l, --latest Show the latest created container (includes all states)
--no-trunc Don't truncate output
-q, --quiet Only display numeric IDs
-s, --size Display total file sizes

2. Execute a log from the container to a file log.txt:

docker logs [OPTIONS] CONTAINER > log.txt

where 'Options':
--details Show extra details provided to logs
-f, --follow Follow log output
--help Print usage
--since string Show logs since timestamp
--tail string Number of lines to show from the end of the logs (default "all")
-t, --timestamps Show timestamps

'Container' is the container found in step 1.

One of the possible error entries is ERROR com.exscudo.peer.core.importer.tasks.SyncSnapshotTask - Unexpected error has occurred: Disabling SyncSnapshotTask

Example

com.exscudo.peer.core.env.tasks.PeerConnect Task - The node is connected. "104.238.???.7:9443".
15:57:41.547 [pool-1-thread-11] INFO com.exscudo.peer.core.importer.tasks.SyncS napshotTask - Snapshot exist, disabling task...
15:57:41.551 [pool-1-thread-11] ERROR com.exscudo.peer.core.importer.tasks.SyncS napshotTask - Unexpected error has occurred: Disabling SyncSnapshotTask
java.lang.RuntimeException: Disabling SyncSnapshotTask
at com.exscudo.peer.core.importer.tasks.SyncSnapshotTask.run(SyncSnapsho tTask.java:67) ~[classes/:?]
at com.exscudo.peer.core.common.tasks.TimedTask.run(TimedTask.java:19) [ classes/:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:51 4) [?:?]
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:305) [?:? ]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask. run(ScheduledThreadPoolExecutor.java:300) [?:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor. java:1167) [?:?]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor .java:641) [?:?]
at java.lang.Thread.run(Thread.java:844) [?:?]

This article explains the cause and the solution to this.

Cause

A snapshot (as per SyncSnapshotTask being the key identifier of the error) is commonly referred to as the state of a system at a particular point in time. In the blockchain context, a snapshot is a copy of the state of accounts, or the current state of the system after the blocks have been imported.

The node can be synchronized by the whole history of the blockchain, or by a snapshot. The snapshot synchronization is inactive by default in EON network. This error is, therefore, a direct consequence of the system avoiding the synchronization by a snapshot. This does not affect the node performance in any way.

Solution

Not required.