2sls opened a new issue, #2656:
URL: https://github.com/apache/arrow-adbc/issues/2656
### What feature or improvement would you like to see?
## Add Server-Side Cursor/Streaming Support to `adbc_driver_postgresql.dbapi`
Maybe I'm missing soemthing, but I’m hitting memory issues with large
PostgreSQL queries in `adbc_driver_postgresql.dbapi` because it fetches full
result sets upfront. PostgreSQL supports server-side cursors (`DECLARE CURSOR`,
`FETCH`) for chunked retrieval, but the driver doesn’t use them natively. I’d
like streaming or cursor support to process big results as Arrow tables in
chunks, avoiding `LIMIT/OFFSET`.
Current behavior:
```python
with adbc_driver_postgresql.dbapi.connect(uri) as conn:
cursor = conn.cursor()
cursor.execute("SELECT * FROM huge_table")
chunk = cursor.fetchmany(1000) # Still loads all rows into memory first
```
Request: Add a `chunk_size` param or `fetch_arrow_stream()` to fetch results
incrementally, e.g.:
```
cursor.execute("SELECT * FROM huge_table", chunk_size=1000)
for chunk in cursor.fetch_arrow_stream():
print(chunk.num_rows) # 1000 rows at a time
```
Could leverage `libpq` cursors or single-row mode. I'm guessing workaround
is manual SQL cursors, but that’s clunky.
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