27000

At a glance

27000 is a source-confirmed trigger-protection condition. PostgreSQL raises it when a row has already been changed by an operation triggered by the current command; the fixed 18.6 source hint points toward using an AFTER trigger when the intent is to propagate changes to other rows. A naive self-updating BEFORE trigger can recurse or alter the trigger semantics, so this entry does not present it as a safe generic reproduction.

Meaning

27000 is the trigger data change violation raised by the executor when a tuple has already been modified by an operation triggered by the current command. The fixed trigger.c path is specifically a same-command, same-tuple guard for a trigger-driven change; it is not a label for every trigger exception or recursive trigger.

Diagnosis

Start with the target relation, the statement's affected row, and the BEFORE row triggers that can update that row. The fixed primary template is tuple to be updated was already modified by an operation triggered by the current command, with a hint to consider an AFTER trigger for propagating changes to other rows. A self-update test that merely recurses is a different failure and does not establish this path. This batch has no natural runtime observation, so record the actual transaction state from the client if a real trigger error occurs.

Response

If the trigger is propagating a change to another row, an AFTER trigger or one set-based statement may fit the intended semantics; redesign the trigger when the same tuple is legitimately targeted twice. Do not respond with a generic retry or CASCADE, and do not claim that rolling back a fabricated self-update reproduces 27000. Roll back a genuinely failed explicit transaction before issuing repair SQL.

Versions

The locked facts table records catalogue presence across the project snapshot range. The fixed source evidence is limited to the path stated below; no exact behavioral introduction or broader runtime coverage is inferred from the definition alone.

Related

Compare 44000 WITH CHECK OPTION violation for a view invariant and 23514 check violation for a table constraint.

Sources

• src.errcodes.18.6 (SHA-256 6e8de346643ba84aa3c9c6a73360acfc7b2dfb89162c06c08ce9bf5bcd5bbcba)
• source path (SHA-256 0a539af85b0de1a04779f92202e7bfc77d85ae6da1747ea32527c67f39084fbd)

Source evidence

Evidence belongs to the frozen source and runtime versions listed here. It is not a runtime verification of the selected manual version.

• src/backend/utils/errcodes.txt · REL_18_6 ·
  724edf9bde9d356724ad384a2e196edc3c9f80f7
• raw/calls/REL_18_6.jsonl · ·
• src/backend/commands/trigger.c · REL_18_6 ·
  724edf9bde9d356724ad384a2e196edc3c9f80f7

Message templates

tuple to be updated was already modified by an operation triggered by the current command

Consider using an AFTER trigger instead of a BEFORE trigger to propagate changes to other rows.

Reproduction & repair cases

Recorded runtime evidence

No runtime observation is attached to this entry.