feat(issue-search): Check max_candidates to push Postgres fields to post-filtering

[snigdhas]

When applying query filters from Postgres, pre-filtering the results before passing the query to Snuba can break if it hits the max size that ClickHouse is able to process (sentry issue). This also manifests as a possible bug in the serializer, though that's more of a red herring since ClickHouse won't be able to handle the query either way.

To work around this, I'm applying the pattern used in the PostgresSnubaQueryExecutor to determine whether to pre- or post-filter the results based on the number of group_ids in the filter. If the number of groups in the pre-filter exceeds the max_candidates, we'll apply the filter after the Snuba query in a post-filtering step right before the pagination happens.

The tests confirm that the is:linked and is:unlinked queries work as a pre- and post-filter dependent on the value configured in snuba.search.max-pre-snuba-candidates.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.18%. Comparing base (b403ecc) to head (684b430).
Report is 87 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #74531       +/-   ##
===========================================
+ Coverage   56.96%   78.18%   +21.22%     
===========================================
  Files        6459     6691      +232     
  Lines      285436   299601    +14165     
  Branches    49078    51568     +2490     
===========================================
+ Hits       162597   234258    +71661     
+ Misses     118412    59019    -59393     
- Partials     4427     6324     +1897     

Files	Coverage Δ
src/sentry/search/snuba/executors.py	93.98% <100.00%> (+43.50%)	⬆️

... and 2117 files with indirect coverage changes

[vartec]

LGTM, I've added some suggestion to simplify the logic a bit.

[vartec]

going back to the comment above, if you reset group_ids_to_pass_to_snuba to None when too_many_candidates, not need to change anything here

[vartec]

Suggested change

	if (
	group_ids_to_pass_to_snuba is not None
	and len(group_ids_to_pass_to_snuba) > max_candidates
	):
	metrics.incr("snuba.search.too_many_candidates", skip_internal=False)
	too_many_candidates = True
	group_ids_to_pass_to_snuba = []
	if (too_many_candidates := (len(group_ids_to_pass_to_snuba) > max_candidates)):
	metrics.incr("snuba.search.too_many_candidates", skip_internal=False)
	group_ids_to_pass_to_snuba = None

You can keep this within same if that starts in line 1663, because that's the only way you'll have any candidates.

Reseting to None when there are too many candidates will simplify some checks below.