array_subscript_error (SQLSTATE 2202E) appears when you reference an array element with an invalid subscript – most often a position that is out of bounds or zero.
array_subscript_error occurs when a PostgreSQL query references an array index that is zero, negative, or larger than the array’s length. Check the subscript, add bounds tests, or use array_length() to validate the index before access to resolve the error.
array_subscript_error
PostgreSQL raises SQLSTATE 2202E when an array element is accessed with an invalid index. Subscripts must start at 1 and stay within the array’s upper bound. Any deviation signals the runtime to abort the statement.
The error can surface in SELECT, UPDATE, INSERT, or PL/pgSQL blocks where array slicing or assignment is used.
The condition appears during loops over arrays, in JSON-to-array conversions, or when user-supplied positions are passed unchecked.
It also shows up when rows contain NULL arrays and your code assumes at least one element.
Uncaught array_subscript_error halts the current transaction, undoing any preceding changes inside the block. In long-running ETL or application calls, that rollback wastes resources and can mask deeper data issues.
Invalid indices (0, negatives, or > upper bound) are the primary cause. Nullable arrays, dynamic truncation, or parameter mishandling also lead to out-of-range access.
Data corruption is rare but possible in older versions.
Validate the index with array_length(), cardinality(), or COALESCE checks before access. Guard user input and wrap assignments in CASE expressions. For loops, iterate FROM 1 TO array_upper(arr,1).
1) User picks nth element: confirm n <= array_length(arr,1). 2) JSONB array indexing: cast to text[] then test bounds. 3) PL/pgSQL bulk updates: use FOREACH.
Never assume array length.
Store size in a separate column or compute on read. Add CHECK constraints to enforce minimum length. In Galaxy, enable inline execution warnings to catch invalid indices during query design.
array_out_of_bounds in other DBMSs, subscript out of range in PL/pgSQL, JSONB_path_error for invalid JSON element access. All share the remedy: validate indices before use.
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No. PostgreSQL arrays always start at index 1. Any attempt to use 0 triggers array_subscript_error.
Yes, wrap risky code in BEGIN ... EXCEPTION WHEN array_subscript_error THEN ... END to handle gracefully.
Galaxy’s inline execution preview shows array lengths, while AI copilot suggests bounds checks, reducing accidental invalid subscripts.
Not usually. The error is by design. Upgrading only helps if a version-specific bug corrupts array bounds.
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