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Add necessary support for arrow-backed table UDFs #75

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1e9a07a
Add necessary support for arrow-backed table UDFs
wmTJc9IK0Q Dec 1, 2025
8d4936b
Copilot comments
wmTJc9IK0Q Dec 1, 2025
a58b93b
Temp go.mod replace for CI
wmTJc9IK0Q Dec 1, 2025
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7 changes: 7 additions & 0 deletions arrow.go
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Original file line number Diff line number Diff line change
Expand Up @@ -301,3 +301,10 @@
defer r.mu.Unlock()
return r.err
}

// MoveArrowToDataChunk moves a record batch into an existing DuckDB DataChunk.
// Useful for implementing table functions that read from Arrow sources.
func (a *Arrow) MoveArrowToDataChunk(rec arrow.RecordBatch, chunk DataChunk) error {
ed := arrowmapping.MoveArrowToDataChunk(a.conn.conn, rec, chunk.chunk)

Check failure on line 308 in arrow.go

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GitHub Actions / Test Arrow (ubuntu-latest, 1.24) 

undefined: arrowmapping.MoveArrowToDataChunk

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GitHub Actions / Test Arrow (macos-latest, 1.24) 

undefined: arrowmapping.MoveArrowToDataChunk

Check failure on line 308 in arrow.go

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GitHub Actions / Test Arrow (windows-latest, 1.24) 

undefined: arrowmapping.MoveArrowToDataChunk
return errorDataError(ed)
}
93 changes: 93 additions & 0 deletions arrow_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@ import (
"context"
"database/sql"
"database/sql/driver"
"fmt"
"sync"
"testing"

Expand Down Expand Up @@ -315,3 +316,95 @@ func TestArrowClosedConn(t *testing.T) {
})
require.Error(t, err)
}

func TestArrowTableUDF(t *testing.T) {
db := openDbWrapper(t, ``)
defer closeDbWrapper(t, db)

conn := openConnWrapper(t, db, context.Background())
defer closeConnWrapper(t, conn)

c := newConnectorWrapper(t, ``, nil)
defer closeConnectorWrapper(t, c)

innerConn := openDriverConnWrapper(t, c)
defer closeDriverConnWrapper(t, &innerConn)

ar, err := NewArrowFromConn(innerConn)
require.NoError(t, err)

// Create an arrow array of type Float64 buffered in memory
schema := arrow.NewSchema([]arrow.Field{
{Name: "col0", Type: arrow.PrimitiveTypes.Float64},
}, nil)
alloc := memory.NewGoAllocator()
builder := array.NewFloat64Builder(alloc)
defer builder.Release()

// Add values > data chunk size to test multiple chunks
for range 10000 {
builder.Append(float64(0.5))
}

arr := builder.NewArray()
rb := array.NewRecordBatch(schema, []arrow.Array{arr}, int64(arr.Len()))
tbl := array.NewTableFromRecords(schema, []arrow.RecordBatch{rb})

RegisterTableUDF(conn, "get_arrow", ChunkTableFunction{
BindArguments: func(named map[string]any, args ...any) (ChunkTableSource, error) {
return &arrowTableUdf{tbl: tbl, ar: ar}, nil
},
})

res, err := db.QueryContext(context.Background(), `SELECT * FROM get_arrow()`)
require.NoError(t, err)
defer closeRowsWrapper(t, res)

var rowCount int
for res.Next() {
var val float64
require.NoError(t, res.Scan(&val))
require.Equal(t, 0.5, val)
rowCount++
}
require.Equal(t, 10000, rowCount)
}

// Define a table UDF
type arrowTableUdf struct {
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@wmTJc9IK0Q wmTJc9IK0Q Dec 1, 2025

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It could make sense to expose a utility UDF struct for this, such as NewArrowTableUDF(duckdb.Arrow, arrow.Table). Then library users would only need to write the BindArguments function to construct the arrow.Table from their existing dataset.

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@VGSML VGSML Dec 1, 2025

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Yes, it would be nice to have a separate registration method related to the Arrow and separate UDF type for the arrow data, Could you please wrap the existing chunked table UDF or create a new one?

ar *Arrow
tbl arrow.Table
rdr *array.TableReader
}

func (u *arrowTableUdf) Init() {
u.rdr = array.NewTableReader(u.tbl, int64(GetDataChunkCapacity()))
}

func (u *arrowTableUdf) ColumnInfos() []ColumnInfo {
t, _ := NewTypeInfo(TYPE_DOUBLE)
return []ColumnInfo{{
Name: "col0",
T: t,
}}
}

func (u *arrowTableUdf) Cardinality() *CardinalityInfo {
return &CardinalityInfo{
Cardinality: uint(u.tbl.NumRows()),
Exact: true,
}
}

func (u *arrowTableUdf) FillChunk(chunk DataChunk) error {
if u.rdr.Next() {
b := u.rdr.RecordBatch()
defer b.Release()
if err := u.ar.MoveArrowToDataChunk(b, chunk); err != nil {
return fmt.Errorf("failed to move arrow to data chunk: %w", err)
}
chunk.SetSize(int(b.NumRows()))
}

return nil
}
3 changes: 2 additions & 1 deletion arrowmapping/arrow_mapping.go
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Original file line number Diff line number Diff line change
Expand Up @@ -36,5 +36,6 @@ var (
NewArrowSchema = bindings.NewArrowSchema
DataChunkToArrowArray = bindings.DataChunkToArrowArray
SchemaFromArrow = bindings.SchemaFromArrow
DataChunkFromArrow = bindings.DataChunkFromArrow
DataChunkFromArrow = bindings.NewDataChunkFromArrow
MoveArrowToDataChunk = bindings.MoveArrowToDataChunk
)
3 changes: 2 additions & 1 deletion arrowmapping/arrow_mapping_darwin_amd64.go
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Original file line number Diff line number Diff line change
Expand Up @@ -36,5 +36,6 @@ var (
NewArrowSchema = bindings.NewArrowSchema
DataChunkToArrowArray = bindings.DataChunkToArrowArray
SchemaFromArrow = bindings.SchemaFromArrow
DataChunkFromArrow = bindings.DataChunkFromArrow
DataChunkFromArrow = bindings.NewDataChunkFromArrow
MoveArrowToDataChunk = bindings.MoveArrowToDataChunk
)
3 changes: 2 additions & 1 deletion arrowmapping/arrow_mapping_darwin_arm64.go
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Original file line number Diff line number Diff line change
Expand Up @@ -36,5 +36,6 @@ var (
NewArrowSchema = bindings.NewArrowSchema
DataChunkToArrowArray = bindings.DataChunkToArrowArray
SchemaFromArrow = bindings.SchemaFromArrow
DataChunkFromArrow = bindings.DataChunkFromArrow
DataChunkFromArrow = bindings.NewDataChunkFromArrow
MoveArrowToDataChunk = bindings.MoveArrowToDataChunk
)
3 changes: 2 additions & 1 deletion arrowmapping/arrow_mapping_linux_amd64.go
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Original file line number Diff line number Diff line change
Expand Up @@ -36,5 +36,6 @@ var (
NewArrowSchema = bindings.NewArrowSchema
DataChunkToArrowArray = bindings.DataChunkToArrowArray
SchemaFromArrow = bindings.SchemaFromArrow
DataChunkFromArrow = bindings.DataChunkFromArrow
DataChunkFromArrow = bindings.NewDataChunkFromArrow
MoveArrowToDataChunk = bindings.MoveArrowToDataChunk
)
3 changes: 2 additions & 1 deletion arrowmapping/arrow_mapping_linux_arm64.go
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Original file line number Diff line number Diff line change
Expand Up @@ -36,5 +36,6 @@ var (
NewArrowSchema = bindings.NewArrowSchema
DataChunkToArrowArray = bindings.DataChunkToArrowArray
SchemaFromArrow = bindings.SchemaFromArrow
DataChunkFromArrow = bindings.DataChunkFromArrow
DataChunkFromArrow = bindings.NewDataChunkFromArrow
MoveArrowToDataChunk = bindings.MoveArrowToDataChunk
)
3 changes: 2 additions & 1 deletion arrowmapping/arrow_mapping_windows_amd64.go
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Original file line number Diff line number Diff line change
Expand Up @@ -36,5 +36,6 @@ var (
NewArrowSchema = bindings.NewArrowSchema
DataChunkToArrowArray = bindings.DataChunkToArrowArray
SchemaFromArrow = bindings.SchemaFromArrow
DataChunkFromArrow = bindings.DataChunkFromArrow
DataChunkFromArrow = bindings.NewDataChunkFromArrow
MoveArrowToDataChunk = bindings.MoveArrowToDataChunk
)
2 changes: 2 additions & 0 deletions go.mod
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Original file line number Diff line number Diff line change
Expand Up @@ -34,3 +34,5 @@ require (
golang.org/x/xerrors v0.0.0-20240903120638-7835f813f4da // indirect
gopkg.in/yaml.v3 v3.0.1 // indirect
)

replace github.com/duckdb/duckdb-go-bindings => github.com/wmTJc9IK0Q/duckdb-go-bindings v0.0.0-20251201050337-6b010671d08c
4 changes: 2 additions & 2 deletions go.sum
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Original file line number Diff line number Diff line change
Expand Up @@ -6,8 +6,6 @@ github.com/apache/thrift v0.22.0 h1:r7mTJdj51TMDe6RtcmNdQxgn9XcyfGDOzegMDRg47uc=
github.com/apache/thrift v0.22.0/go.mod h1:1e7J/O1Ae6ZQMTYdy9xa3w9k+XHWPfRvdPyJeynQ+/g=
github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/duckdb/duckdb-go-bindings v0.1.23 h1:sJRXraxfC/gdHI2T7oHqrdp1VdKemrgqWGQ8986mH1c=
github.com/duckdb/duckdb-go-bindings v0.1.23/go.mod h1:WA7U/o+b37MK2kiOPPueVZ+FIxt5AZFCjszi8hHeH18=
github.com/duckdb/duckdb-go-bindings/darwin-amd64 v0.1.23 h1:Xyw1fWu4jzOtv2Hqkaehr7f+qbIWNRfBMbZyD+g8dyU=
github.com/duckdb/duckdb-go-bindings/darwin-amd64 v0.1.23/go.mod h1:jfbOHwGZqNCpMAxV4g4g5jmWr0gKdMvh2fGusPubxC4=
github.com/duckdb/duckdb-go-bindings/darwin-arm64 v0.1.23 h1:85Xomx5NxZ+Nt+VepUJzuMYbBTH+nB6JlBXIyJuTovA=
Expand Down Expand Up @@ -50,6 +48,8 @@ github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRI
github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
github.com/wmTJc9IK0Q/duckdb-go-bindings v0.0.0-20251201050337-6b010671d08c h1:DUXYLuHDhiy+pcrgFxQHZo/SxLG3Gun0xAJOnlq1HnA=
github.com/wmTJc9IK0Q/duckdb-go-bindings v0.0.0-20251201050337-6b010671d08c/go.mod h1:WA7U/o+b37MK2kiOPPueVZ+FIxt5AZFCjszi8hHeH18=
github.com/zeebo/assert v1.3.0 h1:g7C04CbJuIDKNPFHmsk4hwZDO5O+kntRxzaUoNXj+IQ=
github.com/zeebo/assert v1.3.0/go.mod h1:Pq9JiuJQpG8JLJdtkwrJESF0Foym2/D9XMU5ciN/wJ0=
github.com/zeebo/xxh3 v1.0.2 h1:xZmwmqxHZA8AI603jOQ0tMqmBr9lPeFwGg6d+xy9DC0=
Expand Down
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