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Informix Error -626: Cannot obtain or set serial value.

Cause and resolution

Cannot obtain or set serial value.

This internal error message does not refer to a problem with a SERIAL or SERIAL8 or BIGSERIAL column in a table that you defined. The database server uses unique integer values for many purposes (for example, the table ID number for a new or altered table). An internal error has made it impossible to generate a new, unique number. For example, in host systems that use files for locking, something might have prevented the creation of a lock file. Check the accompanying ISAM error code for more information. If the error recurs, note all circumstances and contact IBM Informix Technical Support.

Oninit® Troubleshooting Guidance

Reasons / Common Causes

-626 is flagged by the official text as an internal error — and, per the official guidance, it does not refer to an application-defined SERIAL/SERIAL8/BIGSERIAL column. It fires when the server itself fails to generate one of its own internal unique integer values (used for things like a new table's internal table-ID number), which on some host systems depends on being able to create a lock file.

  1. A failure creating a lock file, per the official guidance's specific example, on host systems that use files for internal locking — a permissions or disk-space problem in the directory the server uses for these lock files.
  2. A genuine internal engine condition generating the next unique internal ID, per the official guidance's framing, with no other documented application-level cause.
Solutions / Resolution
  1. Check the accompanying ISAM error code, per the official guidance, for the specific underlying reason.
  2. Check for a lock-file creation problem, per the official guidance's specific example, on platforms where the server uses filesystem-based locking — verify permissions and free space in the relevant directory.
  3. If this recurs after ruling out a lock-file problem, note all circumstances and contact IBM Informix Technical Support, per the official guidance.
Examples
Checking for a lock-file problem
$ ls -ld /path/to/informix/lock/directory
$ df -h /path/to/informix/lock/directory

Confirm the server's OS user has write permission and there's free space in the directory it uses for internal lock files, on platforms where this locking mechanism applies.

Diagnostic Checks
  1. Check the accompanying ISAM error code first, per the official guidance.
  2. Check permissions and free space on the lock-file directory, per the official guidance's specific example, before escalating.
Related Errors / Related Topics

No closely related error codes are cross-referenced for -626 in this set yet.

Despite the "serial value" name, this is about the server's own internal unique-ID generation, not an application-defined SERIAL column — check for a lock-file creation problem first, per the official guidance's specific example.