alibaba/druid · critical · GetConnectionTimeoutException

wait millis {waitMillis}, active {activeCount}, maxActive {m

Error message

wait millis {waitMillis}, active {activeCount}, maxActive {maxActive}, creating {creatingCount}

What it means

GetConnectionTimeoutException (a SQLException subclass) thrown from getConnection() when no pooled connection could be obtained within maxWait, AND the pool had previously recorded a connection-creation error (createError != null). The creation error is chained as the cause, so this is really a 'pool exhausted because creation is failing' diagnosis: the real reason lives in the cause.

Source

Thrown at core/src/main/java/com/alibaba/druid/pool/DruidDataSource.java:1769

            }

            List<JdbcSqlStatValue> sqlList = this.getDataSourceStat().getRuningSqlList();
            for (int i = 0; i < sqlList.size(); ++i) {
                if (i != 0) {
                    buf.append('\n');
                } else {
                    buf.append(", ");
                }
                JdbcSqlStatValue sql = sqlList.get(i);
                buf.append("runningSqlCount ").append(sql.getRunningCount());
                buf.append(" : ");
                buf.append(sql.getSql());
            }

            String errorMessage = buf.toString();

            if (createError != null) {
                throw new GetConnectionTimeoutException(errorMessage, createError);
            } else {
                throw new GetConnectionTimeoutException(errorMessage);
            }
        }

        holder.incrementUseCount();

        return new DruidPooledConnection(holder);
    }

    public void handleConnectionException(
            DruidPooledConnection pooledConnection,
            Throwable t,
            String sql
    ) throws SQLException {
        final DruidConnectionHolder holder = pooledConnection.getConnectionHolder();
        if (holder == null) {
            return;

View on GitHub (pinned to fa8dc99126)

Solutions

1. Read getNextException / getCause() of the thrown GetConnectionTimeoutException — the createError there is the actual failure (auth refused, connection refused, socket timeout).
2. Verify jdbcUrl, username, password, driver class and network reachability to the DB host/port (telnet/nc) from the app host.
3. Confirm the JDBC driver jar matches the DB version and is on the classpath; check DriverManager can create a raw connection with the same URL outside the pool.
4. Tune maxActive / maxWait upward only after the creation error is fixed; a saturated-but-healthy pool throws error 44, not this one.

Example fix

// before: root cause hidden
catch (GetConnectionTimeoutException e) { log.error(e.getMessage()); }

// after: surface the chained creation error
catch (GetConnectionTimeoutException e) {
    Throwable cause = e.getCause();
    log.error("pool borrow timed out; underlying create error: {}", cause, cause);
}

// preflight: can we even open a raw connection with these credentials/url?
// run once at startup, not per request
try (Connection raw = DriverManager.getConnection(jdbcUrl, user, pwd)) {
    assert raw.isValid(2);
}

try {
    return dataSource.getConnection();
} catch (GetConnectionTimeoutException e) {
    Throwable cause = e.getCause();
    if (cause != null) {
        // createError is the real reason (auth refused, connection refused)
        log.error("borrow timed out due to create failure: {}", cause);
    }
    throw e;
}

When it happens

Trigger: holder is null after the wait loop (line 1714), createError field is non-null (a prior createPhysicalConnection attempt threw), so line 1769 fires. Produces a message like 'wait millis X, active Y, maxActive Z, creating W, createErrorCount N' plus the chained createError. Happens when the DB is unreachable/unauthenticated and the pool simultaneously empties out.

Common situations: Wrong DB url/credentials/host/port; DB down or refusing connections; firewall dropping the socket so every creation attempt fails while in-flight requests drain the pool; driver class/version mismatch causing creation errors; maxActive saturated while create keeps erroring.

Related errors

• connection closed
• connection disabled
• validationQuery didn't return a row
• maxWaitThreadCount {}, current wait Thread count {}
• onFatalError, activeCount {}, onFatalErrorMaxActive {}

AI-assisted analysis of alibaba/druid@fa8dc99126 (2026-08-14). Data as JSON: /api/errors/45c2e9d8b3e3cd94. Report an issue: GitHub.