KNOX-3252: Handle duplicate object exception during postgres table cr…

[hanicz]

…eation race condition

KNOX-3252 - Intermittent Postgres type already exists exception

What changes were proposed in this pull request?

The issue is a race condition during table creation when multiple Knox instances are starting up simultaneously. At the initial "isTableExists" check the tables are not yet created. So Knox-instance-0 and Knox-instance-1 will both go ahead with the creation. Postgres will create a record in pg_class and pg_type as well. However the process that gets there later will get the exception due to the record that was created by the other process in pg_type.

2026-02-10 21:19:44,825 ERROR knox.gateway (TokenStateServiceFactory.java:createService(63)) - Error while initiatalizing org.apache.knox.gateway.services.token.impl.JDBCTokenStateService: Error while initiating JDBCTokenStateService: org.postgresql.util.PSQLException: ERROR: type "knox_tokens" already exists

This change catches the duplicate object SQL state and skips the table creation.

How was this patch tested?

Manually tested with a local setup. I had postgres running in docker desktop and a local Knox instance.

    <property>
        <name>gateway.service.tokenstate.impl</name>
        <value>org.apache.knox.gateway.services.token.impl.JDBCTokenStateService</value>
    </property>
    <property>
        <name>gateway.database.type</name>
        <value>postgresql</value>
    </property>
    <property>
        <name>gateway.database.port</name>
        <value>5432</value>
    </property>
    <property>
        <name>gateway.database.host</name>
        <value>localhost</value>
    </property>
    <property>
        <name>gateway.database.name</name>
        <value>mydb</value>
    </property>

I created the below type in the Postgres DB to simulate the race condition

CREATE TYPE knox_tokens AS ENUM ('active', 'expired', 'revoked');

Integration Tests

N/A

UI changes

N/A

[pzampino]

Not necessarily for this PR, but I wonder if executing these in a single Statement execution might help minimize the potential for the "already exists" error while improving efficiency slightly.

[smolnar82]

The problem is that not all the supported DB vendors have CREATE TALE IF EXISTS support (or at least this was true a couple years ago).

[hanicz]

target knox: failed to solve: image "docker.io/apache/knox-dev:local": already exists
Docker tests are failing with the above. Its unrelated to the changes