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08P01

PostgreSQL 08P01: protocol_violation

Verified with sources3 sourcesReviewed Aug 23, 2026
Trace

Evidence linked to this decision

View source: PostgreSQL 18 Appendix A: Error Codes

Risk level

High

Professional inspection is recommended.

Urgency

Medium

Quick answer

SQLSTATE 08P01 (protocol_violation) means a client, driver or intermediary broke the PostgreSQL wire protocol. Diagnose the named condition before retrying.

Safety first

Safe checks you can perform

  • Isolate the protocol participant

What a technician must be able to justify

A technician is coming

These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.

These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.

    Before accepting a part or repair

    Nothing has been shown yet. Do not accept a part swap based on the code alone.

    Follow these steps

    Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.

    1. Isolate the protocol participant

      Tools required

      Capture the server log and exact driver, pooler and proxy versions. Reproduce once without intermediaries using a supported driver; if the direct path works, add components back one at a time. Do not loop identical protocol bytes against production.

      Evidence: PostgreSQL 18 Appendix A: Error Codes · PostgreSQL error and notice fields · PostgreSQL database connection control functions

    Still not solved

    If the error persists, stop here. See what the technician must do and show you.

    Virtual technician

    Does 08P01 still appear after these checks?

    This guided flow uses the exact code and your answers to choose a test, an expected result and the next branch.

    Where this code applies

    A code is meaningful only inside the right product and version context.

    Primary scope

    System
    Software and systems
    Brand
    PostgreSQL
    Product type
    Database

    Known code variants

    • PostgreSQL 08P01
    • protocol_violation
    • SQLSTATE 08P01

    What it means

    PostgreSQL assigns 08P01 to protocol_violation in Class 08 — Connection Exception. Applications should branch on the stable SQLSTATE and structured error fields, not localized message text.

    Symptoms and causes

    Probable causes · in order

    • Likely trigger in this requestCommon

      A malformed or out-of-order protocol message reached the server, often around a driver, pooler, proxy or custom protocol implementation.

      Evidence: PostgreSQL 18 Appendix A: Error Codes · PostgreSQL error and notice fields · PostgreSQL database connection control functions

    Sources and technical references

    1. 1

      PostgreSQL 18 Appendix A: Error Codes

      PostgreSQL Global Development Group · 2026 · official_doc

    2. 2

      PostgreSQL error and notice fields

      PostgreSQL Global Development Group · 2026 · official_doc

    3. 3

      PostgreSQL database connection control functions

      PostgreSQL Global Development Group · 2026 · official_doc

    Sources: PostgreSQL 18 Appendix A: Error Codes · PostgreSQL error and notice fields · PostgreSQL database connection control functionsreviewed 2026-08-23 · verified

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