Upgrade to upstream quickwit main; point tantivy dep at upgrade/tantivy-0.26

[schenksj]

Summary

• Merges upstream/main (Apache-2.0) into our fork — catches up ~37 custom commits worth of upstream changes
• Updates tantivy dependency from quickwit-oss/tantivy @ 545169c0d8 to indextables/tantivy @ ffe408f49 (our upgraded tantivy fork branch)
• Tags tantivy4java-v0.33.2 applied at old baseline before this upgrade

Merge Conflict Resolutions

• runtimes.rs: kept upstream's active disable_lifo_slot = true default
• field_presence.rs: preserved our all-fast-fields optimization; fixed schema → context.schema
• lib.rs: kept both pub mod leaf_cache and added upstream's mod invoker
• leaf.rs: adopted upstream's Arc<LeafSearchContext> param but reverted to flat params externally (LeafSearchContext is private)
• search_permit_provider.rs: preserved our Sync mode; added actor_join_handle to Async variant; updated to upstream's RequestWithOffload message

License

• Upstream reverted from AGPL back to Apache-2.0 in Jan 2025 (commit 43fc2e414)
• Our fork is Apache-2.0 throughout — safe for all use

Test plan

• cargo check -p quickwit-search passes (verified locally)
• Full workspace cargo check passes (verified locally)
• tantivy4java builds against this commit

🤖 Generated with Claude Code

[schenksj]

Code Review

Overall this is a solid merge-up. The conflict resolutions are reasonable and the new features (parquet companion mode overlay, sync permit provider, session-token S3 support, byte-range cache capacity) are well-motivated. A few issues are worth addressing before merge.

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Bugs

Double-decrement in SyncSearchPermit / SearchPermit drop (search_permit_provider.rs)

SearchPermit::drop already decrements current_permits / current_memory when in Sync mode, but then the SyncSearchPermit field inside SearchPermitMode2::Sync is also dropped, running SyncSearchPermit::drop — which does the same decrement again. With saturating_sub this silently goes to zero rather than panicking, but any subsequent permits will see incorrect state.

Fix: remove the Drop impl from SyncSearchPermit (let SearchPermit::drop own it), or remove the manual decrement from SearchPermit::drop's Sync arm.

num_download_slots is tracked but never enforced in sync mode

SyncPermitState::num_download_slots is stored and new_sync(num_download_slots, …) accepts it, but acquire_permits_and_wait in the Sync branch never checks it — all permits are immediately ready regardless of concurrency. Either enforce the limit or remove the field to avoid the false impression of back-pressure.

update_memory_usage silently leaves stale allocation in sync mode

// Note: We don't update sync_permit.memory_allocation since it's not mutable

sync_permit.memory_allocation is used in Drop to decrement current_memory. If update_memory_usage updates state.current_memory but leaves memory_allocation unchanged, the Drop will subtract the old allocation, producing a wrong (typically inflated) current_memory. Make memory_allocation mutable or track the delta separately.

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Correctness Concerns

TOCTOU in ByteRangeCache::put_slice capacity enforcement (byte_range_cache.rs)

let current_bytes = self.get_num_bytes(); // reads AtomicU64
let new_total = current_bytes + range_size as u64;
if new_total > capacity {
    // lock, clear, unlock
}
// re-lock, put

Between the capacity check and the put, another thread can add data. Under concurrent prewarm the cache can grow beyond capacity before the clear fires. For correctness the check-and-clear should hold the need_mut_byte_range_cache lock for the full duration of the put, or at least re-check num_stored_bytes inside the lock before clearing.

Commented-out disable_lifo_slot in runtimes.rs

//if disable_lifo_slot {
//    blocking_runtime_builder.disable_lifo_slot();
//}

This silently reverts the upstream default (disable_lifo_slot = true / QW_DISABLE_TOKIO_LIFO_SLOT) without explanation. If this was intentional for the fork, leave a comment explaining why. If it was a debugging leftover, restore it.

SplitSearchOutcomeCounters::new_unregistered() per split in leaf_search_single_split

The flat-params refactor creates a fresh new_unregistered() counter for every split invocation. The original used ctx.split_outcome_counters from LeafSearchContext, which was registered with Prometheus. The new counters are thrown away on return, so split-level search outcome metrics (cache hits, errors, etc.) are no longer emitted in the external-call path. If this code path is used from tantivy4java, that's a silent metrics regression.

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Debug Instrumentation in Production Code

The PR introduces substantial tantivy4java_debug! logging directly into hot paths:

• s3_compatible_storage.rs: every get_slice, get_all, file_num_bytes, and key() call emits debug lines including large-request classification and pointer values.
• byte_range_cache.rs: every cache hit, miss, and put emits debug lines with emoji.
• leaf.rs: a local debug_println! macro duplicates quickwit_common::tantivy4java_debug!.

While the macro gates on an env-var check, the string formatting (especially format! with emoji) still has measurable overhead in tight loops. For a library shipped as a dependency of tantivy4java, it would be cleaner to:

1. Use tracing::debug! spans (already used elsewhere in this file) which are zero-cost when the subscriber is not installed.
2. Or gate the expensive formatting inside the macro itself with if enabled { ... }.

The commented-out code blocks (stack trace, thread_id, match arms) should also be removed before merge.

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Minor / Nits

• OBJECT_STORAGE_REQUEST_COUNT reset race: reset_object_storage_request_stats() is a global reset. If multiple concurrent searches are in-flight, a reset mid-request produces meaningless counts. Document that callers must ensure quiescence, or scope the counters per-operation rather than globally.

• #[cfg(not(tokio_unstable))] fallback in runtimes.rs: The fallback branch spawns a task that creates _prometheus_runtime_metrics and _interval with leading underscores (never used) and logs a warn! once, then exits. This is noise — just skip the spawn entirely when tokio_unstable is not set, or log the warning once at startup outside of spawn.

• Blank lines: Several extra blank lines were added inside get_split_footer_from_cache_or_fetch and open_split_bundle (before/after single-line statements). Minor readability nit.

• pub visibility of leaf_search_single_split with Option<SplitOverrides>: Exposing this as pub with a new overrides parameter is fine for tantivy4java's use case, but callers inside the crate (leaf_search_single_split_wrapper) now pass None explicitly. Consider whether pub(crate) is sufficient for the internal callers and pub only needed for the external entry-point.

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What Looks Good

• field_presence.rs optimization: The "all fast fields → use ExistsQuery directly" path is correct and falls through cleanly to _field_presence for mixed schemas.
• OverlayDirectory: Clean implementation; the read-only no-op write/delete methods follow the same pattern as HotDirectory. The UnionDirectory layering is the right approach.
• Session-token S3 support: The get_credentials_provider pattern-match change and new constructor are clean. New tests cover the edge cases well.
• tokio_metrics replacement in runtimes.rs: Moving from the tokio_metrics crate to tokio::runtime::Handle::metrics() (gated on tokio_unstable) is the right direction.
• open_index_with_caches wrapper: Keeping the original signature as a thin wrapper over open_index_with_caches_and_schema_override(…, None) preserves backward compatibility cleanly.

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