feat: enhance range handling in MSSQL and Postgres extractors; update partition range generator logic

internal/app/etl/extractors/mssql.go

@@ -30,6 +30,8 @@ func buildExtractQueryMssql(
 	includeRange bool,
 	isMinInclusive bool,
 	isMaxInclusive bool,
+	hasMin bool,
+	hasMax bool,
 ) string {
 	var sbQuery strings.Builder
 
@@ -53,24 +55,33 @@ func buildExtractQueryMssql(
 
 	fmt.Fprintf(&sbQuery, " FROM [%s].[%s]", tableInfo.Schema, tableInfo.Table)
 
-	if includeRange {
-		fmt.Fprintf(&sbQuery, " WHERE [%s]", tableInfo.PrimaryKey)
+	if includeRange && (hasMin || hasMax) {
+		sbQuery.WriteString(" WHERE ")
+
+		if hasMin {
+			fmt.Fprintf(&sbQuery, "[%s]", tableInfo.PrimaryKey)
 			if isMinInclusive {
 				sbQuery.WriteString(" >=")
 			} else {
 				sbQuery.WriteString(" >")
 			}
+			sbQuery.WriteString(" @min")
+		}
 
-		sbQuery.WriteString(" @min AND ")
+		if hasMin && hasMax {
+			sbQuery.WriteString(" AND ")
+		}
+
+		if hasMax {
 			fmt.Fprintf(&sbQuery, "[%s]", tableInfo.PrimaryKey)
 			if isMaxInclusive {
 				sbQuery.WriteString(" <=")
 			} else {
 				sbQuery.WriteString(" <")
 			}
-
 			sbQuery.WriteString(" @max")
 		}
+	}
 
 	fmt.Fprintf(&sbQuery, " ORDER BY [%s] ASC", tableInfo.PrimaryKey)
 
@@ -114,14 +125,16 @@ func (mssqlEx *MssqlExtractor) Exec(
 	indexPrimaryKey int,
 	chBatchesOut chan<- models.Batch,
 ) (int, error) {
-	query := buildExtractQueryMssql(tableInfo, columns, partition.HasRange, partition.Range.IsMinInclusive, partition.Range.IsMaxInclusive)
+	hasMin := partition.HasRange && partition.Range.Min > 0
+	hasMax := partition.HasRange && partition.Range.Max > 0
+	query := buildExtractQueryMssql(tableInfo, columns, partition.HasRange, partition.Range.IsMinInclusive, partition.Range.IsMaxInclusive, hasMin, hasMax)
 
 	var queryArgs []any
-	if partition.HasRange {
-		queryArgs = append(queryArgs,
-			sql.Named("min", partition.Range.Min),
-			sql.Named("max", partition.Range.Max),
-		)
+	if hasMin {
+		queryArgs = append(queryArgs, sql.Named("min", partition.Range.Min))
+	}
+	if hasMax {
+		queryArgs = append(queryArgs, sql.Named("max", partition.Range.Max))
 	}
 
 	rowsRead := 0

internal/app/etl/extractors/postgres.go

@@ -27,6 +27,8 @@ func buildExtractQueryPostgres(
 	includeRange bool,
 	isMinInclusive bool,
 	isMaxInclusive bool,
+	hasMin bool,
+	hasMax bool,
 ) string {
 	var sbColumns strings.Builder
 
@@ -54,20 +56,34 @@ func buildExtractQueryPostgres(
 
 	query := fmt.Sprintf(`SELECT %s FROM "%s"."%s"`, sbColumns.String(), sourceDbInfo.Schema, sourceDbInfo.Table)
 
-	if includeRange {
-		query += fmt.Sprintf(` WHERE "%s"`, sourceDbInfo.PrimaryKey)
+	if includeRange && (hasMin || hasMax) {
+		query += " WHERE "
+		paramIdx := 1
+
+		if hasMin {
+			query += fmt.Sprintf(`"%s"`, sourceDbInfo.PrimaryKey)
 			if isMinInclusive {
 				query += " >="
 			} else {
 				query += " >"
 			}
-		query += " $1 AND " + fmt.Sprintf(`"%s"`, sourceDbInfo.PrimaryKey)
+			query += fmt.Sprintf(" $%d", paramIdx)
+			paramIdx++
+		}
+
+		if hasMin && hasMax {
+			query += " AND "
+		}
+
+		if hasMax {
+			query += fmt.Sprintf(`"%s"`, sourceDbInfo.PrimaryKey)
 			if isMaxInclusive {
 				query += " <="
 			} else {
 				query += " <"
 			}
-		query += " $2"
+			query += fmt.Sprintf(" $%d", paramIdx)
+		}
 	}
 
 	query += fmt.Sprintf(` ORDER BY "%s" ASC`, sourceDbInfo.PrimaryKey)
@@ -84,14 +100,16 @@ func (postgresEx *PostgresExtractor) Exec(
 	indexPrimaryKey int,
 	chBatchesOut chan<- models.Batch,
 ) (int, error) {
-	query := buildExtractQueryPostgres(tableInfo, columns, partition.HasRange, partition.Range.IsMinInclusive, partition.Range.IsMaxInclusive)
+	hasMin := partition.HasRange && partition.Range.Min > 0
+	hasMax := partition.HasRange && partition.Range.Max > 0
+	query := buildExtractQueryPostgres(tableInfo, columns, partition.HasRange, partition.Range.IsMinInclusive, partition.Range.IsMaxInclusive, hasMin, hasMax)
 
 	var queryArgs []any
-	if partition.HasRange {
-		queryArgs = append(queryArgs,
-			partition.Range.Min,
-			partition.Range.Max,
-		)
+	if hasMin {
+		queryArgs = append(queryArgs, partition.Range.Min)
+	}
+	if hasMax {
+		queryArgs = append(queryArgs, partition.Range.Max)
 	}
 
 	rowsRead := 0

internal/app/etl/table_analyzers/main.go

@@ -17,7 +17,7 @@ func PartitionRangeGenerator(
 	rowsPerPartition int64,
 	jobRange config.RangeConfig,
 ) ([]models.Partition, error) {
-	if jobRange.Max > 0 {
+	if jobRange.Min > 0 {
 		return []models.Partition{{
 			Id:           uuid.New(),
 			HasRange:     true,