pg qrep: avro schema nullable by default

Author: serprex

flow/connectors/postgres/qrep_query_executor.go

@@ -5,7 +5,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"log/slog"
-	"maps"
 	"slices"
 
 	"github.com/jackc/pgx/v5"
@@ -68,18 +67,13 @@ func (qe *QRepQueryExecutor) cursorToSchema(
 	tx pgx.Tx,
 	cursorName string,
 ) (types.QRecordSchema, error) {
-	type attId struct {
-		relid uint32
-		num   uint16
-	}
-
 	rows, err := tx.Query(ctx, "FETCH 0 FROM "+cursorName)
 	if err != nil {
 		return types.QRecordSchema{}, fmt.Errorf("failed to fetch 0 for field descriptions: %w", err)
 	}
+	defer rows.Close()
 	fds := rows.FieldDescriptions()
 	tableOIDset := make(map[uint32]struct{})
-	nullPointers := make(map[attId]*bool, len(fds))
 	qfields := make([]types.QField, len(fds))
 	for i, fd := range fds {
 		tableOIDset[fd.TableOID] = struct{}{}
@@ -89,38 +83,17 @@ func (qe *QRepQueryExecutor) cursorToSchema(
 			qfields[i] = types.QField{
 				Name:      fd.Name,
 				Type:      ctype,
-				Nullable:  false,
+				Nullable:  true,
 				Precision: precision,
 				Scale:     scale,
 			}
 		} else {
 			qfields[i] = types.QField{
 				Name:     fd.Name,
 				Type:     ctype,
-				Nullable: false,
+				Nullable: true,
 			}
 		}
-		nullPointers[attId{
-			relid: fd.TableOID,
-			num:   fd.TableAttributeNumber,
-		}] = &qfields[i].Nullable
-	}
-	rows.Close()
-	tableOIDs := slices.Collect(maps.Keys(tableOIDset))
-
-	rows, err = tx.Query(ctx, "SELECT a.attrelid,a.attnum FROM pg_attribute a WHERE a.attrelid = ANY($1) AND NOT a.attnotnull", tableOIDs)
-	if err != nil {
-		return types.QRecordSchema{}, fmt.Errorf("failed to query schema for field descriptions: %w", err)
-	}
-
-	var att attId
-	if _, err := pgx.ForEachRow(rows, []any{&att.relid, &att.num}, func() error {
-		if nullPointer, ok := nullPointers[att]; ok {
-			*nullPointer = true
-		}
-		return nil
-	}); err != nil {
-		return types.QRecordSchema{}, fmt.Errorf("failed to process schema for field descriptions: %w", err)
 	}
 
 	return types.NewQRecordSchema(qfields), nil