Tanmay Ambre created IGNITE-15068:
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Summary: Ignite giving stale data - when data is inserted/updated
and immediately read (from the same client node)
Key: IGNITE-15068
URL: https://issues.apache.org/jira/browse/IGNITE-15068
Project: Ignite
Issue Type: Task
Components: cache
Affects Versions: 2.9.1
Reporter: Tanmay Ambre
Hi,
We have a 18 node (server) cluster for Ignite. We have multiple client nodes
that connect to ignite and use the cache api to get and put data.
One of the client node is a Kafka streams application. This application
receives an event for this event:
# we lookup the data using the key in ignite. i.e. cache.get(key)
# we update the data if we find an entry in ignite i.e. cache.put(key, value)
# we insert the data if we don't find an entry in ignite i.e. cache.put(key,
value)
This application processes more than 30 million events per day. In some
scenarios we get multiple events for the same key "consecutively" i.e. the time
difference between consecutive events is not more than 10 to 20 milliseconds.
We are sure they are processed sequentially as they go to the same Kafka
partition.
What we have observed is sometimes, the step #1 gives us an old copy of the
data (not the one which was updated as part of #2).
for e.g. when we get the first event for the same key, we have following value:
Key = 1, value = \{version: 1}
when we get the second even we update ignite as:
Key = 1, value = \{version: 2} //increment version by 1
when we get the third event and when we lookup the data in ignite instead of
getting \{version: 2}, we get {color:#FF0000}{version: 1}{color}
also sometimes, when we get the second event - we {color:#FF0000}don't even
find the entry in ignite{color} (i.e. \{version:1})
Our caches have the following configuration
backups = 1
atomicityMode = ATOMIC
writeSynchronizationPolicy = PRIMARY_SYNC
readFromBackup = true (default - we are not setting this)
Is there something wrong? Should we set "readFromBackup = false"?
unfortunately it is very difficult to replicate since it happens just a between
50 to 100 times in a day (i.e. out of 30 million events that we are getting).
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