Informix Error -499

Reasons / Common Causes

-499 is a hard row-size limit: a table record can't exceed 32,767 bytes in total, and the attempted operation (CREATE TABLE, ALTER TABLE ADD, or a column-widening ALTER TABLE MODIFY) would push the combined size of all fields past that ceiling.

1. A CREATE TABLE with too many columns, or columns too wide, for the combined row size to fit within 32,767 bytes.
2. ALTER TABLE ADD adding a new column that pushes an already-wide table over the limit.
3. ALTER TABLE MODIFY widening an existing column (e.g. VARCHAR(100) to VARCHAR(500)) on a table that was already close to the row-size ceiling.
4. A schema evolving incrementally over time, with each individual change seeming small but cumulatively approaching the limit.

Solutions / Resolution

1. Review the combined sizes of all fields in the table, per the official guidance, to identify what's pushing the total over 32,767 bytes.
2. Consider splitting a very wide table into two related tables (a 1:1 relationship via a shared key), moving less frequently accessed or larger columns into the second table.
3. Consider using TEXT/BYTE/LVARCHAR for large variable-length content where applicable, since these are typically stored with different size accounting than a fixed in-row CHAR/VARCHAR allocation (confirm against the specific server version's exact accounting rules).
4. Reconsider whether every column genuinely needs its current declared width, especially CHAR/VARCHAR columns sized generously "just in case."

Examples

Checking combined column sizes before adding a new one

SELECT SUM(collength) FROM syscolumns
WHERE tabid = (SELECT tabid FROM systables WHERE tabname = 'wide_table');
-- compare against 32767 minus the new column's intended width

Splitting a table that's approaching the limit

CREATE TABLE orders_core (
    order_id INTEGER PRIMARY KEY,
    customer_id INTEGER,
    status VARCHAR(20)
);

CREATE TABLE orders_detail (
    order_id INTEGER PRIMARY KEY REFERENCES orders_core(order_id),
    notes VARCHAR(2000),
    shipping_instructions VARCHAR(2000)
);

Diagnostic Checks

1. Sum the declared widths of every column in the target table via syscolumns.
2. Compare that sum (plus the intended change) against the 32,767-byte limit.
3. Identify the widest, least-necessary columns as candidates for splitting into a related table or switching to a large-object type.

Related Errors / Related Topics

• -370 — "Cannot drop last column." Another structural ALTER TABLE restriction, in a different context (a table needing at least one column, rather than a total size ceiling).
• -328 — "Column column-name already exists in table." Another ALTER TABLE ADD-time restriction, about naming rather than row-size limits.

Splitting an overly wide table into two related tables (via a shared key) is usually a cleaner fix than trimming column widths across the board, especially for tables that keep growing.