Hi masters, I have created an issue HBASE-26849 <https://issues.apache.org/jira/browse/HBASE-26849> about NPE caused by WAL Compression and Replication.
For this problem, I try to reopen a WAL reader when we reset the position to 0 and it looks like it's working well. But it didn't fundamentally solve the problem. Since we have the WAL Compression feature, Replication has introduced a lot of new code, and there are many places that reset the HLog position, such as seekOnFs to originalPosition. I guess none of these codes consider compatibility with WAL Compression. Because theoretically we can roll back the position to any position at any time, but the LRUCache in the corresponding LRUDictionary should also be rolled back, otherwise the read and write link behavior may be inconsistent. But LRUCache can't roll back at all... So my thought is, open another issue and add some description in the doc, WAL Compression and Replication are not compatible. What do you think? Thank you. Regards
