WindowStore fetch return null

Kafka Streams
1

Hello, i have an issue with the windowStore fetch result.

i have 3 pods, running with the same code. only one of them has the problem.

Here is my code :

var key = "key";
var value = "value";
long timestamp = 181205425

myWindowedStore.put(key, value, timestamp);
var result= myWindowedStore.fetch(key, timestamp);

//result is null on one pod and not null on the others

Retention time and window size are the same (many days).
The null result is the same on this pod if i try 10 minutes later to fetch the key at the same timestamp.

Please help :slight_smile:

2

Hard to say given your description. A few notes:

  • retention time is based on stream-time, not wall-clock time.
  • each store (ie, each shard) tracks stream-time individually

When you try to lookup outside of the retention time, there would be a debug log:

LOG.debug(“Record with key {} is expired as timestamp from key ({}) < actual stream time ({})”,
key.toString(), timestampFromKey, observedStreamTime - retentionPeriod + 1);

Hope this helps.

3

Hi, the 3 pod’s PVC have been deleted, and the related topic also.

The 3 pods were stated again, and the problem is now solved.

But we really can’t understand how we get this issue.