[I] SELECT with leading comment returns empty data, and max_rows is silently bypassed for the same statements [doris-mcp-server]

["mortalBibo (via GitHub)" <gi...@apache.org>]

mortalBibo opened a new issue, #86:
URL: https://github.com/apache/doris-mcp-server/issues/86

   ## Summary
   
   Two related bugs share one root cause: `sql.startswith("SELECT")` is used at two callsites to classify SQL, and it fails when the statement begins with a `--` or `/* */` comment.
   
   **Bug 1 (visible)** — `data: []` while `row_count > 0`:
   
   ```sql
   -- any leading comment
   SELECT col FROM t WHERE dt = '20260509'
   ```
   
   Returns `{"row_count": N, "data": []}`. Removing the leading comment makes it work.
   
   **Bug 2 (latent, masked by Bug 1)** — `max_rows` ignored: the auto-injected `LIMIT {max_rows}` is skipped for the same statements, so large queries can be dispatched unbounded once Bug 1 is fixed.
   
   Affects master / v0.6.1.
   
   ## Root cause
   
   - `db.py:100` — `startswith("SELECT")` false → `else` branch → `data = []`, `row_count = cursor.rowcount` (already populated by the MySQL protocol).
   - `query_executor.py:689` — same false-negative → `LIMIT` not appended.
   
   Same bug class as #62 Bug 5 (missing `WITH`/CTE in the whitelist).
   
   ## Fix
   
   - `db.py`: use `cursor.description` (driver-reported, no SQL parsing). This is exactly @jonasbrami's #75.
   - `query_executor.py`: runs before `cursor.execute`, so use a helper that strips leading comments before extracting the first keyword.
   
   ## PR
   
   I'm opening a PR that continues #75 (commit preserved with original authorship), adds regression tests for the contract, and includes the Bug 2 fix. Happy to close it if @jonasbrami prefers to continue #75.


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Re: [I] SELECT with leading comment returns empty data, and max_rows is silently bypassed for the same statements [doris-mcp-server]

["FreeOnePlus (via GitHub)" <gi...@apache.org>]

FreeOnePlus closed issue #86: SELECT with leading comment returns empty data, and max_rows is silently bypassed for the same statements
URL: https://github.com/apache/doris-mcp-server/issues/86


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