Drop experimental reuse fragments optimization from RS QP

[dariuszkuc]

Drop support for the experimental reuse fragment query optimization from Rust QP. This implementation was not only very slow but also very buggy due to its complexity. experimental_reuse_query_fragments option can be applied for the JS QP only.

Auto generation of fragments is a much simpler (and faster) algorithm that in most cases produces better results. Fragment auto generation is the default optimization since v1.58 release.

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Checklist

Complete the checklist (and note appropriate exceptions) before the PR is marked ready-for-review.

• Changes are compatible¹
• Documentation² completed
• Performance impact assessed and acceptable
• Tests added and passing³
  • Unit Tests
  • Integration Tests
  • Manual Tests

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Notes

Footnotes

1. It may be appropriate to bring upcoming changes to the attention of other (impacted) groups. Please endeavour to do this before seeking PR approval. The mechanism for doing this will vary considerably, so use your judgement as to how and when to do this. ↩

2. Configuration is an important part of many changes. Where applicable please try to document configuration examples. ↩

3. Tick whichever testing boxes are applicable. If you are adding Manual Tests, please document the manual testing (extensively) in the Exceptions. ↩

[svc-apollo-docs]

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[router-perf]

CI performance tests

• connectors-const - Connectors stress test that runs with a constant number of users
• const - Basic stress test that runs with a constant number of users
• demand-control-instrumented - A copy of the step test, but with demand control monitoring and metrics enabled
• demand-control-uninstrumented - A copy of the step test, but with demand control monitoring enabled
• enhanced-signature - Enhanced signature enabled
• events - Stress test for events with a lot of users and deduplication ENABLED
• events_big_cap_high_rate - Stress test for events with a lot of users, deduplication enabled and high rate event with a big queue capacity
• events_big_cap_high_rate_callback - Stress test for events with a lot of users, deduplication enabled and high rate event with a big queue capacity using callback mode
• events_callback - Stress test for events with a lot of users and deduplication ENABLED in callback mode
• events_without_dedup - Stress test for events with a lot of users and deduplication DISABLED
• events_without_dedup_callback - Stress test for events with a lot of users and deduplication DISABLED using callback mode
• extended-reference-mode - Extended reference mode enabled
• large-request - Stress test with a 1 MB request payload
• no-tracing - Basic stress test, no tracing
• reload - Reload test over a long period of time at a constant rate of users
• step-jemalloc-tuning - Clone of the basic stress test for jemalloc tuning
• step-local-metrics - Field stats that are generated from the router rather than FTV1
• step-with-prometheus - A copy of the step test with the Prometheus metrics exporter enabled
• step - Basic stress test that steps up the number of users over time
• xlarge-request - Stress test with 10 MB request payload
• xxlarge-request - Stress test with 100 MB request payload

[dariuszkuc]

followup: we'll need to update the docs at https://www.apollographql.com/docs/graphos/reference/router/configuration#fragment-generation-and-reuse

[goto-bus-stop]

We should also make sure that people aren't opting back into the old algorithm en masse in 1.58.0. But this is a very exciting diff 😁

[lrlna]

This PR also needs to update docs for fragment generation and reuse.

Otherwise really exciting to get rid of all the dead code!!

[lrlna]

I am so sorry, I read a tracing::warn message you wrote and realised this is going to need a config migration. For the time being it can be a log, and for the next release we can do a delete.

[lrlna]

Hm, we are going to need a migration for this config going away, I just realised. At this point it can be a log rather than a delete, but it should go through our regular "migration" process rather than adhoc, I think.

[lrlna]

Thank you!