@Override
    public void close() {
        if (isSharedOpExecutorOwned) {
            try {
                if (sharedOperationExecutor != null && !sharedOperationExecutor.isShutdown()) {
                    this.sharedOperationExecutor.shutdownNow();
                }
            } catch (Exception e) {
                LOG.error("Failed to close shared operation executor", e);
            }
        } else {
            LOG.debug("Skip closing operation executor because not owned by client");
        }

        if (httpClientHelper != null) {
            httpClientHelper.close();
        }
    }
Frees the resources associated with the client.
<ul>
    <li>Shuts down the shared operation executor by calling {@code shutdownNow()}</li>
</ul>
client-v2/src/main/java/com/clickhouse/client/api/Client.java