Ignite read stale data from backup node - backup

Question

I ran into in-consistency data issues on ignite version 2.8.1. I have three nodes run as a cluster and the cache configuration as:
CacheConfiguration<String, Balance> cacheConfiguration = new CacheConfiguration<>(Balance.class.getSimpleName());
cacheConfiguration.setIndexedTypes(String.class, Balance.class);
cacheConfiguration.setSqlIndexMaxInlineSize(100);
cacheConfiguration.setSqlSchema("PUBLIC");
cacheConfiguration.setAtomicityMode(CacheAtomicityMode.TRANSACTIONAL);
cacheConfiguration.setCacheMode(CacheMode.PARTITIONED);
cacheConfiguration.setBackups(4);
cacheConfiguration.setWriteSynchronizationMode(CacheWriteSynchronizationMode.FULL_SYNC);
Then I have very simple code to add balance in a loop:
for (int i = 0; i < 10000; i++) {
balance = balanceDao.findByKey(accountId, "USD");
balance.setQuantity(balance.getQuantity().add(BigDecimal.ONE));
balanceDao.save(balance);
}
when run above on the primary node, I always have balance increased 10000 correctly, however when run that on backup node, sometimes my balance increased around 8k, and sometimes 9k.
if setWriteSynchronizationMode was set to PRIMARY_SYNC and setReadFromBackup was set to false, I can get correct balance on all nodes.
is this a bug on 2.8.1 or anything wrong with my configuration?

Answer 1

If readFromBackup == true (which is the default), it is possible to read stale values on the backup nodes. Set it to false to avoid stale reads.