jackc/pgx · error

array header

Error message

array header: %w

What it means

While decoding a binary array, reading the fixed-size header portion failed — the buffer ran short or the reader errored. The wrapped error is from the pgio reader, typically unexpected EOF on truncated array data.

Solutions

1. Verify the binary array data is complete and not truncated
2. Check that the column actually contains an array type
3. Inspect the wrapped error for the reader's specific failure
4. Test with a simple array value to isolate the issue

When it happens

Trigger: Thrown at pgtype/array.go:51 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: /api/errors/8e5206a887313082. Report an issue: GitHub.

Appendix: source

Thrown at pgtype/array.go:51

	}

	elementCount := int(dimensions[0].Length)
	for _, d := range dimensions[1:] {
		elementCount *= int(d.Length)
	}

	if elementCount < 0 {
		return 0
	}

	return elementCount
}

func (dst *arrayHeader) DecodeBinary(r *pgio.Reader) error {
	// Each dimension is 8 bytes, which also bounds the Dimensions allocation below.
	numDims := r.Count(8)
	if err := r.Err(); err != nil {
		return fmt.Errorf("array header: %w", err)
	}

	if numDims > 6 {
		return fmt.Errorf("array has too many dimensions: %d", numDims)
	}

	dst.ContainsNull = r.Uint32() == 1
	dst.ElementOID = r.Uint32()

	dst.Dimensions = make([]ArrayDimension, numDims)
	for i := range dst.Dimensions {
		dst.Dimensions[i].Length = r.Int32()
		dst.Dimensions[i].LowerBound = r.Int32()
	}

	if err := r.Err(); err != nil {
		return fmt.Errorf("array header: %w", err)
	}

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