tree aeb40d9b537286382ee6395ef41e7a579db3a512
parent 19f7e67c86a8eca1dcca72c76ab7076451dd649c
author Kaushik Lingarkar <kaushik.lingarkar@linaro.org> 1660769847 -0700
committer Kaushik Lingarkar <kaushik.lingarkar@linaro.org> 1663111093 -0700

Introduce a SEARCH_AFTER index pagination type

Current Paginated interface only allows to restart a query from
a given offset. Update it to also allow restarting queries using
a searchAfter key. searchAfter can help with performance of queries
such as [1] where the visibility is being queried for an account
that cannot see most/all changes. [1] finishes in ~45 mins with
OFFSET and ~10 mins with SEARCH_AFTER when the site has around
1M abandoned changes.

Index config has been updated to add a paginationType entry with
OFFSET and SEARCH_AFTER as supported values. The default is set
to OFFSET to keep the current pagination type unchanged.

Gerrit's Lucene index implementation has been updated to support
this new pagination type with search-after[2]. Elasticsearch
index implementation has also been updated to paginate using
search-after[3] and can be further improved to use PIT[4]. Lucene
and Elasticsearch tests have been updated to run with both pagination
types. Also, Elasticsearch tests now use the official docker image
as it can handle running tests with multiple index config suites.

Note that, searchAfter will not impact using offsets in Gerrit
query APIs.

[1] gerrit query 'status:abandoned visibleto:guest'
[2] https://lucene.apache.org/core/6_6_5/core/org/apache/lucene/search/IndexSearcher.html#search-org.apache.lucene.search.Query-int-org.apache.lucene.search.Sort-boolean-boolean-
[3] https://www.elastic.co/guide/en/elasticsearch/reference/current/paginate-search-results.html#search-after
[4] https://www.elastic.co/guide/en/elasticsearch/reference/current/point-in-time-api.html

Release-Notes: Index searches now support search-after pagination
Change-Id: If3f8d914d5fd3f350c026cf099f08cf9a13f2195