Slow indexing speed when collection size is large

[Zheng Lin Edwin Yeo]

Hi,

I'm using Solr 6.4.2.

Would like to check, if there are alot of collections in my Solr which has
very large index size, will the indexing speed be affected?

Currently, I have created a new collections in Solr which has several
collections with very large index size, and the indexing speed is much
slower than expected.

Regards,
Edwin