POC for rewriting queries with Caggs, add early validations

[natalya-aksman]

POC currently checks whether queries can be rewritten with Caggs and rewrites queries with Caggs if it can.

GUCs enable_cagg_rewites and cagg_rewrites_debug_info are OFF by default. If only cagg_rewrites_debug_info is ON diagnostics on whether query can be rewritten with Caggs will be printed but query won't be rewritten.

Only real-time Caggs are currently considered as candidates.
Reaggregation is out of scope for this POC i.e. we look for exact match on time buckets and aggregates provided by Caggs.

Validation methods in tsl/src/continuous_aggs/common.c were refactored so they could be reused by Cagg rewrites validations.

PG15 is currently not supported as view queries in PG15_LE have dummy range table entries which complicates expression matching. As we plan to stop PG15 support in 6 months it seems like an unnecessary complication to deal with.

TODO:

• Comprehensive unit tests covering all negative and positive cases
• Dealing with Hierarchical Caggs rewrites
• Matching on equivalent expressions as in "a=5" matches "5=a".
• Dealing with params, making sure all matches are done on immutable expressions.
• Matching LATERAL subqueries in Caggs
• Checking whether Caggs have active invalidations to exclude them from the candidates

Issue #9225 should complete "Query rewrites with Caggs" project by adding fully real-time mode which, for each Cagg used in a query, will combine materialized data plus live data above the current Cagg watermark and live data from current Cagg invalidated ranges.

Completing #9225 will ensure that for every query eligible to be rewritten with Caggs we will use as much materialized data as possible while still providing the same output whether the query was rewritten with a Cagg or not.

[github-actions]

@melihmutlu, @svenklemm: please review this pull request.

Powered by pull-review

[codecov]

Codecov Report

❌ Patch coverage is 85.21401% with 114 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.86%. Comparing base (5e3ae2e) to head (f16bfca).

Files with missing lines	Patch %	Lines
tsl/src/continuous_aggs/common.c	72.19%	35 Missing and 27 partials ⚠️
tsl/src/continuous_aggs/rewrite_with_caggs.c	90.24%	20 Missing and 23 partials ⚠️
src/import/setrefs.c	92.42%	1 Missing and 4 partials ⚠️
src/ts_catalog/continuous_agg.c	83.33%	1 Missing and 1 partial ⚠️
src/planner/expand_hypertable.c	0.00%	0 Missing and 1 partial ⚠️
src/planner/planner.c	85.71%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8967      +/-   ##
==========================================
+ Coverage   85.72%   85.86%   +0.14%     
==========================================
  Files         245      247       +2     
  Lines       48167    48806     +639     
  Branches    10748    10937     +189     
==========================================
+ Hits        41289    41909     +620     
- Misses       3522     3572      +50     
+ Partials     3356     3325      -31     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.