sryanyuan opened a new pull request, #3146:
URL: https://github.com/apache/kvrocks/pull/3146
Pattern-based SCAN iterations may skip remaining keys in a hash slot,
causing incomplete key retrieval.
**Bug Reproduction:**
- 10 keys in the same hash slot: ["119483", "166988", "210695", "223656",
"48063", "59022", "65976", "74937", "88379", "99338"]
- Initial SCAN with pattern `2*`:
- Returns cursor C1 and **empty keyset** (no keys match `2*`)
- Records "119483" as last scanned key
- Subsequent SCAN with cursor C1 and same pattern:
1. RocksDB iterator seeks to "119483"
2. Calls `Next()` → gets "166988" (next key in slot)
3. "166988" ∉ `2*` pattern → no key returned
4. **Error**: Scan incorrectly increments slot index
5. **Result**: Remaining 8 keys in slot are skipped
**Bug Fix Implementation:**
When scanning with a previous scan cursor and match pattern:
1. If the last scanned key is lexicographically before the pattern's start
range:
→ Use the pattern's minimum matching key as the seek key
→ Instead of using the last scanned key
**Example:**
- Pattern: `2*` → Minimum matching key = `"2"` (hex: \x32)
- Last scanned key: `"119483"` (hex: \x31\x31...)
- Since `"119483"` < `"2"` lexically:
✓ **Correct:** Seek to `"2"`
✗ **Buggy:** Seek to `"119483"`
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