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https://github.com/openobserve/openobserve.git
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Loakesh Indiran
148a7a706e
## Bug
Queries with `ORDER BY` on a non-timestamp column and `size: -1`
(unlimited) returned empty results when the TopKHeap path was active.
## Root Cause
In `execution.rs`, when `size = -1`, `original_size` was computed as
`0`:
```rust
let original_size = if req.query.size > 0 { req.query.size as usize } else { 0 };
// Per-partition: size = (from + 0) = 0 → partition fetches 0 rows
```
Every partition received `size=0`, so `TopKHeap` got no rows and
returned `[]`.
## Fixes
**`streaming/execution.rs`**
- When `size=-1`: use `ZO_QUERY_DEFAULT_LIMIT` as `heap_k` instead of 0
- Keep `size=-1` for per-partition requests so each partition returns
all its data
**`streaming/sorting.rs` — `TopKHeap::new`**
- Guard: `k=0` falls back to `ZO_QUERY_DEFAULT_LIMIT` (safety net;
`execution.rs` fix prevents this in practice)
## Fixed Behavior
Queries with non-ts `ORDER BY` and `size=-1` now correctly:
- Use `ZO_QUERY_DEFAULT_LIMIT` rows as the heap bound
- Send `size=-1` to each partition (not `size=0`)
- Return results instead of `[]`
Note: CTE and subquery queries that have no `_timestamp` in the outer
result take a **single partition** path (via `ts_column=None`) and never
reach `TopKHeap` — fixed in the enterprise repo (see companion PR).
## Tests
7 new `TopKHeap` unit tests in `sorting.rs`:
- Bounded `k` evicts correctly
- `k=1000` (unlimited) keeps all rows
- `from` offset applied after drain
- ASC order
- Multi-partition push
- `size=-1` non-ts ORDER BY (all rows survive)
- `k=0` fallback guard
## Test Queries (against a stream with `level`, `_timestamp` fields)
```sql
-- Should return data, correct DESC order
SELECT level, COUNT(*) as cnt FROM "stream" GROUP BY level ORDER BY cnt DESC
-- size: -1
-- Bounded
SELECT level, COUNT(*) as cnt FROM "stream" GROUP BY level ORDER BY cnt DESC
-- size: 10, from: 0
-- Paginated
SELECT level, COUNT(*) as cnt FROM "stream" GROUP BY level ORDER BY cnt DESC
-- size: 5, from: 5
```
## Related
Enterprise companion PR: openobserve/o2-enterprise#1727 (fix: suppress
_timestamp wildcard default for CTE and inline subquery sources)