FW: Why are cursor mark queries recommended over regular start, rows combination?

-----Original Message-----
From: S G [mailto:sg.online.email@gmail.com]
Sent: 13 March 2018 05:48
To: solr-user@lucene.apache.org
Subject: Why are cursor mark queries recommended over regular start, rows
combination?

Hi,

We have use-cases where some queries will return about 100k to 500k records.
As per https://lucene.apache.org/solr/guide/7_2/pagination-of-results.html,
it seems that using start=x, rows=y is a bad combination performance wise.

1) However, it is not clear to me why the alternative: "cursor-query" is
cheaper or recommended. It would have to run the same kind of workload as
the normal start=x, rows=y combination, no?

2) Also, it is not clear if the cursory-query runs on a single shard or uses
the same scatter gather as regular queries to read from all the shards?

3) Lastly, it is not clear the role of export handler. It seems that the
export handler would also have to do exactly the same kind of thing as
start=0 and rows=1000,000. And that again means bad performance.

What is the difference between all of the 3


Thanks
SG