On 2/14/23 20:02, Natarajan, Rajeswari wrote:
Would like to know if it is possible to upgrade standalone solr from 4.x to 8.x
Is there a wiki available. Please let me know.
In most cases when jumping more than one major version you will have to
completely reindex from scratch.
You can't upgrade it step-by-step to one major version at a time,
because starting in one of the 6.x versions, the Lucene version that
originally wrote each segment is recorded and never gets updated or
removed. If a segment has no version or the earliest version recorded
is less than 7.0, then 8.x will refuse to open it. 9.x is similar for
anything older than 8.0.
I have seen a tool that bypasses this version check, allowing upgrades
that Lucene prevents. Even if you did use that tool and managed to get
it to work, it's a bad idea, which is why it's explicitly blocked.
Thanks,
Shawn
