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Informix Error -709

-709 TEXT and BYTE column column-name is already clustered.

You have already created an optical cluster using the named column. Because a single column can be part of only one optical cluster, your attempt to create a new cluster on this column has failed.

Oninit® Troubleshooting Guidance

Reasons / Common Causes

-709 fires when CREATE OPTICAL CLUSTER's FOR clause names a column that's already part of a different optical cluster — per the official guidance, a single column can only be part of one optical cluster.

  1. A column already clustered elsewhere named in a new CREATE OPTICAL CLUSTER statement — the direct, only cause.
  2. A misunderstanding of the intended cluster structure, attempting to add a column to a second cluster rather than realizing it needs to be part of the existing one instead (or a redesigned single cluster covering both).
Solutions / Resolution
  1. Identify which existing cluster already contains the column, and either use that cluster instead of creating a new one, or drop it first if it genuinely needs to be restructured.
  2. Drop the existing cluster if it needs to be redefined to group columns differently:
    DROP OPTICAL CLUSTER old_cluster;
CREATE OPTICAL CLUSTER new_cluster FOR content_a, content_b ...;
  3. Remove the already-clustered column from the new CREATE OPTICAL CLUSTER statement, if it should remain part of its original cluster.
Examples
The disallowed attempt
CREATE OPTICAL CLUSTER cluster_a FOR content_a ...;
CREATE OPTICAL CLUSTER cluster_b FOR content_a, content_b ...;
-- -709: content_a is already part of cluster_a
Corrected — drop and redefine as one cluster
DROP OPTICAL CLUSTER cluster_a;
CREATE OPTICAL CLUSTER cluster_b FOR content_a, content_b ...;
Diagnostic Checks
  1. Identify which existing optical cluster already contains the named column, via whatever catalog/administrative view the Optical Subsystem exposes for clusters.
Related Errors / Related Topics
  • -708 — "Optical cluster cluster-name already exists." A related optical-cluster restriction, about the new cluster's own name colliding, rather than one of its columns already belonging elsewhere.

A column can belong to only one optical cluster — drop and redefine, or remove the already-clustered column from the new statement.