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refactor(mdb): remove dummy bind_col workaround in query #91

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Merged
lewiszlw merged 2 commits into from
Jun 22, 2026
Merged

refactor(mdb): remove dummy bind_col workaround in query #91

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62b1cab
refactor(mdb): remove dummy bind_col workaround from query path
lewiszlw Jun 22, 2026
bd819b5
chore: trigger CI
lewiszlw Jun 22, 2026
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24 changes: 1 addition & 23 deletions remote-table/src/connection/mdb/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,7 @@ use datafusion_physical_plan::stream::RecordBatchStreamAdapter;
use futures::lock::Mutex;
use log::debug;
use odbc_api::Environment;
use odbc_api::handles::{AsStatementRef, SqlResult, SqlText, Statement, StatementImpl};
use odbc_api::handles::{SqlResult, SqlText, Statement, StatementImpl};
use odbc_api::{Cursor, CursorImpl};
use std::collections::HashMap;
use std::path::PathBuf;
Expand Down Expand Up @@ -249,28 +249,6 @@ impl Connection for MdbConnection {
))
})?;

// mdbtools 1.0.x requires SQLBindCol before SQLFetch — without it,
// SQLFetch hangs indefinitely. odbc-api's Cursor::next_row() calls
// SQLFetch without binding columns.
//
// Workaround: bind a single dummy column (column 1) to allow
// SQLFetch to proceed, then use the row-by-row Cursor::next_row()
// path which calls SQLGetData for each cell. SQLGetData after
// SQLBindCol works because the dummy buffer is ignored.
let mut dummy = odbc_api::Nullable::<i32>::null();
match unsafe { cursor.as_stmt_ref().bind_col(1, &mut dummy) } {
SqlResult::Success(()) | SqlResult::SuccessWithInfo(()) => {}
SqlResult::Error { function } => {
return Err(DataFusionError::Execution(format!(
"{function} failed binding dummy column for mdb"
)));
}
other => {
return Err(DataFusionError::Execution(format!(
"Unexpected result binding dummy column: {other:?}"
)));
}
}
let mut exhausted = false;

loop {
Expand Down