jackc/pgx · error

PostgreSQL array has %d dimensions but slice has %d dimensio

Error message

PostgreSQL array has %d dimensions but slice has %d dimensions

What it means

Error "PostgreSQL array has %d dimensions but slice has %d dimensions" thrown in jackc/pgx.

Source

Thrown at pgtype/builtin_wrappers.go:870

	case 0:
		// Empty, but non-nil array
		slice := reflect.MakeSlice(sliceType, 0, 0)
		a.slice.Set(slice)
		return nil
	case 1:
		elementCount := cardinality(dimensions)
		slice := reflect.MakeSlice(sliceType, elementCount, elementCount)
		a.slice.Set(slice)
		return nil
	default:
		sliceDimensionCount := 1
		lowestSliceType := sliceType
		for ; lowestSliceType.Elem().Kind() == reflect.Slice; lowestSliceType = lowestSliceType.Elem() {
			sliceDimensionCount++
		}

		if sliceDimensionCount != len(dimensions) {
			return fmt.Errorf("PostgreSQL array has %d dimensions but slice has %d dimensions", len(dimensions), sliceDimensionCount)
		}

		elementCount := cardinality(dimensions)
		flatSlice := reflect.MakeSlice(lowestSliceType, elementCount, elementCount)

		multiDimSlice := a.makeMultidimensionalSlice(sliceType, dimensions, flatSlice, 0)
		a.slice.Set(multiDimSlice)

		// Now that a.slice is a multi-dimensional slice with the underlying data pointed at flatSlice change a.slice to
		// flatSlice so ScanIndex only has to handle simple one dimensional slices.
		a.slice = flatSlice

		return nil
	}
}

func (a *anyMultiDimSliceArray) makeMultidimensionalSlice(sliceType reflect.Type, dimensions []ArrayDimension, flatSlice reflect.Value, flatSliceIdx int) reflect.Value {
	if len(dimensions) == 1 {

View on GitHub (pinned to ec1a0befd2)

When it happens

Trigger: Thrown at pgtype/builtin_wrappers.go:870 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of jackc/pgx@ec1a0befd2 (2026-08-04). Data as JSON: /data/errors/114444d61b434088.json. Report an issue: GitHub.