quarkusio/quarkus · error · java.lang.IllegalStateException

Duplicate pool name:

Error message

Duplicate pool name: 

What it means

ReactiveDatasourceHealthCheck aggregates one Vert.x pool per configured reactive datasource, keyed by datasource name. During initialization addPool() puts each pool into a map; if a second pool registers under a name already present, it throws IllegalStateException because health checks would collide and report ambiguous results.

Source

Thrown at extensions/reactive-datasource/runtime/src/main/java/io/quarkus/reactive/datasource/runtime/ReactiveDatasourceHealthCheck.java:44

    private static final Logger log = Logger.getLogger(ReactiveDatasourceHealthCheck.class);

    private final Map<String, PoolHealthEntry> pools = new ConcurrentHashMap<>();
    private final String healthCheckResponseName;
    private final String defaultHealthCheckSQL;

    protected ReactiveDatasourceHealthCheck(String healthCheckResponseName, String defaultHealthCheckSQL) {
        this.healthCheckResponseName = healthCheckResponseName;
        this.defaultHealthCheckSQL = defaultHealthCheckSQL;
    }

    protected void addPool(String name, Pool pool) {
        addPool(name, pool, defaultHealthCheckSQL);
    }

    protected void addPool(String name, Pool pool, String healthCheckSQL) {
        final PoolHealthEntry previous = pools.put(name, new PoolHealthEntry(pool, healthCheckSQL));
        if (previous != null) {
            throw new IllegalStateException("Duplicate pool name: " + name);
        }
    }

    @Override
    public HealthCheckResponse call() {
        HealthCheckResponseBuilder builder = HealthCheckResponse.named(healthCheckResponseName);
        builder.up();

        for (Map.Entry<String, PoolHealthEntry> poolEntry : pools.entrySet()) {
            final String dataSourceName = poolEntry.getKey();
            final PoolHealthEntry entry = poolEntry.getValue();
            try {
                CompletableFuture<Void> databaseConnectionAttempt = new CompletableFuture<>();
                Context context = Vertx.currentContext();
                if (context != null) {
                    log.debug("Run health check on the current Vert.x context");
                    context.runOnContext(v -> {
                        entry.pool.query(entry.healthCheckSQL)

View on GitHub (pinned to e1c734241f)

Solutions

1. Check application.properties for duplicate quarkus.datasource."<name>" blocks and make each datasource name unique
2. If creating datasources programmatically, ensure each is added to the health check only once
3. Review custom subclasses of ReactiveDatasourceHealthCheck for duplicate addPool calls
4. Quarkus version-upgrade check: remove duplicate ReactiveDatasourceHealthCheck bean registrations (e.g. @Produces plus built-in)

Example fix

// before (duplicate names)
quarkus.datasource."db".reactive.url=...
quarkus.datasource."db".reactive.url=...
// after
quarkus.datasource."orders".reactive.url=...
quarkus.datasource."users".reactive.url=...

Set<String> names = new HashSet<>();
for (String ds : List.of("<ds1>", "<ds2>")) {
    if (!names.add(ds)) throw new IllegalStateException("Duplicate datasource name: " + ds);
}

try {
    healthCheck.addPool(name, pool, sql);
} catch (IllegalStateException e) {
    log.errorf("Duplicate pool registration: %s", e.getMessage());
    throw e; // fail fast at startup
}

When it happens

Trigger: addPool() called twice with the same datasource name — typically two health-check instances or pool registrations for the same named datasource, or programmatic datasource creation reusing a name already registered.

Common situations: Registering multiple reactive datasources with duplicate quarkus.datasource."name" identifiers; custom code extending ReactiveDatasourceHealthCheck and re-adding a pool; extension re-initialization after config reload.

Related errors

• TLS configuration name '' is set but the TLS registry is not
• Unable to find the TLS configuration '' for the reactive dat
• Failed to load application configuration
• Failed to initialize application configuration
• Unrecognized option for quarkus.bootstrap.misaligned-platfor

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/15ee977fa1aa127f. Report an issue: GitHub.