Thanks so much Erick. Sounds like this should be a perfect approach to helping
resolve our current issue.
On 2/24/20, 6:48 PM, "Erick Erickson" <erickerick...@gmail.com> wrote:
Thomas:
Yes, upgrading to 7.5+ will automagically take advantage of the
improvements, eventually... No, you don’t have to reindex.
The “eventually” part. As you add, and particularly replace, existing
documents, TMP will make decisions based on the new policy. If you’ve optimized
in the past and have a very large segment (I.e. > 5G), it’ll be rewritten when
the number of deleted docs exceeds the threshold; I don’t remember what the
exact number is. Point is it’ll recover from having an over-large segment over
time and _eventually_ the largest segment will be < 5G.
Absent a previous optimize making a large segment, I’d just consider
optimizing after you’ve upgraded. The TMP revisions respect the max segment
size, so that should purge all deleted documents from your index without
creating a too-large one. Thereafter the number of deleted docs should remain <
about 33%. It only really approaches that percentage when you’re updating lots
of existing docs.
Finally, expungeDeletes is less expensive than optimize because it doesn’t
rewrite segments with 10% deleted docs so that’s an alternative to optimizing
after upgrading.
Best,
Erick
> On Feb 24, 2020, at 5:42 PM, Zimmermann, Thomas
<tzimmerm...@techtarget.com> wrote:
>
> Hi Folks –
>
> Few questions before I tackled an upgrade here. Looking to go from 7.4 to
7.7.2 to take advantage of the improved Tiered Merge Policy and segment cleanup
– we are dealing with some high (45%) deleted doc counts in a few cores. Would
simply upgrading Solr and setting the cores to use Lucene 7.7.2 take advantage
of these features? Would I need to reindex to get existing segments merged more
efficiently? Does it depend on the size of my current segments vs the
configuration of the merge policy or would upgrading simply allow solr to do
its own thing help mitigate this issue?
>
> Also – I noticed the 7.5+ defaults to the Autoscaling for replication,
and 8.0 defaults to legacy. Would I potentially need to make changes to my
existing configs to ensure they stay on Legacy replication?
>
> Thanks much!
> TZ
>
>
>
