make concurrent object store calls configurable

[nikhilsinhaparseable]

add env P_MAX_OBJECT_STORE_REQUESTS default to 1000
controls how many concurrent calls DF makes to object store

also, add metric_name bloom filter for otel-metrics

Summary by CodeRabbit

• New Features

  • Added configurable limits for concurrent object-storage requests across S3, GCS, and Azure Blob Storage.
  • Added the P_MAX_OBJECT_STORE_REQUESTS setting, with a default limit of 1,000 requests.
  • Improved metric-name filtering for OpenTelemetry metrics through Parquet bloom filters.

• Bug Fixes

  • Preserved consistent histogram metric flattening behavior.

[coderabbitai]

Walkthrough

The PR makes object-store request limits configurable per backend, adds a bloom filter to the OTel metric_name Parquet column, and reformats the histogram branch in metric flattening without changing its returned value.

Changes

Configurable object-store request limits

Layer / File(s)	Summary
Storage limit configuration contract src/storage/mod.rs, src/storage/azure_blob.rs, src/storage/gcs.rs, src/storage/s3.rs	A public default constant and P_MAX_OBJECT_STORE_REQUESTS-backed fields are added to the storage backend configurations.
Apply configured request limits src/storage/azure_blob.rs, src/storage/gcs.rs, src/storage/s3.rs	DataFusion runtime and client construction paths use each backend’s configured LimitStore request cap.

OTel metric storage metadata

Layer / File(s)	Summary
Metric flattening and Parquet properties src/otel/metrics.rs, src/parseable/streams.rs	The histogram match arm retains its tuple result, and OTel metric_name columns enable bloom filters with NDV 32768.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Possibly related PRs

• parseablehq/parseable#1720: Both PRs modify histogram-related OTel metric flattening logic.

Suggested reviewers:parmesant

Poem

A rabbit hops through metrics bright,
Bloom filters guard names just right.
Storage limits now obey each tune,
S3, GCS, Azure under the moon.
Histograms keep their tuple hue—
“A tidy change!” the bunny coos.

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description mentions the new env var and bloom filter, but omits the required issue reference, rationale, key changes, and checklist.	Add the issue link if applicable, expand the goal/rationale and key changes, and fill out the testing/comments/documentation checklist.
Docstring Coverage	⚠️ Warning	Docstring coverage is 62.50% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly reflects the main change: making object-store concurrency configurable.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Inline comments:
In `@src/parseable/streams.rs`:
- Around line 737-741: Correct the Bloom-filter explanation in the surrounding
comment: state that it can reject definite non-membership, while false positives
may still allow a row group containing no matching metric to be read. Do not
describe Bloom membership as exact or claim that every row group without the
metric is rejected.
In `@src/storage/azure_blob.rs`:
- Around line 132-139: Reject zero for max_object_store_requests in the CLI
argument definitions for src/storage/azure_blob.rs lines 132-139,
src/storage/gcs.rs lines 105-112, and src/storage/s3.rs lines 170-177. Update
each clap parser to enforce a minimum value of 1 using a NonZeroUsize parser or
equivalent custom validation, preserving the existing default and usize
configuration behavior.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 7e42cb77-0527-420d-be93-04c5f74e9e84

📥 Commits

Reviewing files that changed from the base of the PR and between e6ba9bd and c1aa6c4.

📒 Files selected for processing (6)

• src/otel/metrics.rs
• src/parseable/streams.rs
• src/storage/azure_blob.rs
• src/storage/gcs.rs
• src/storage/mod.rs
• src/storage/s3.rs