[PR] Fix ``SnowflakeHook`` transaction support: multi-statement SQL and `AUTOCOMMIT` [airflow]

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

kaxil opened a new pull request, #65040:
URL: https://github.com/apache/airflow/pull/65040

   Fixes two longstanding issues with `SnowflakeHook.run()` that broke Snowflake transaction support:
   
   1. **Multi-statement SQL with `split_statements=False`** (#48233): When sending a multi-statement block like `BEGIN; INSERT ...; COMMIT;` as a single `cursor.execute()` call, Snowflake rejects it because the connector defaults `MULTI_STATEMENT_COUNT=1`. Now passes `num_statements=0` (auto-detect) to `cursor.execute()` when `split_statements=False`.
   
   2. **AUTOCOMMIT session parameter override** (#30236): Users who set `session_parameters={"AUTOCOMMIT": True}` on their connection had it immediately overridden by `set_autocommit(conn, False)` in `run()`. Now respects the session parameter when `autocommit=False` (the default).
   
   ## Design rationale
   
   **Why override `_run_command()` instead of modifying `run()` inline?** The base `DbApiHook._run_command()` handles logging, lineage tracking, and row counts. Overriding it in `SnowflakeHook` keeps the `num_statements` logic close to `cursor.execute()` while preserving all side effects. The override drops the psycopg list-to-tuple conversion since Snowflake never uses psycopg.
   
   **Why case-insensitive AUTOCOMMIT check?** Snowflake session parameters are case-insensitive, so users may write `{"autocommit": True}` or `{"AUTOCOMMIT": True}`. The check normalizes to uppercase.
   
   **Why set `conn.autocommit_mode = True` in the else branch?** When we skip `set_autocommit()` to respect the session parameter, `get_autocommit()` would return `False` (since `autocommit_mode` was never set), causing a redundant `conn.commit()` at the end of `run()`. Setting the mode explicitly avoids this.
   
   **Why `_get_static_conn_params` instead of `_get_conn_params()`?** The static version is a `@cached_property` and doesn't trigger OAuth token refresh, avoiding surprise HTTP requests from what should be a simple config check.
   
   ## Validated against real Snowflake
   
   All three scenarios pass against a real Snowflake instance:
   - Multi-statement block (CREATE + INSERT + SELECT + DROP) with `split_statements=False`
   - Transaction block (CREATE + BEGIN + INSERT x3 + COMMIT) with `split_statements=False`
   - Backward compat: `split_statements=True` (default) still works with separate query IDs
   
   Closes #48233
   Closes #30236


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Re: [PR] Fix ``SnowflakeHook`` transaction support: multi-statement SQL and `AUTOCOMMIT` [airflow]

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

kaxil commented on PR #65040:
URL: https://github.com/apache/airflow/pull/65040#issuecomment-4227524732

   cc @josh-fell 


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Re: [PR] Fix ``SnowflakeHook`` transaction support: multi-statement SQL and `AUTOCOMMIT` [airflow]

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

kaxil merged PR #65040:
URL: https://github.com/apache/airflow/pull/65040


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