Search Engine

The Search Engine Query Service service can be found on the Search Engine tab. The Search Engine Query service forwards queries to the indexer for the appropriate search collection(s), and retrieves and returns the results of those queries. This service must be started and running before a search collection can be queried.

From the Status tab, you can start, restart, and stop the service. You can also choose to configure the service to ignore pings. This is done to test distributed search, and is sometimes done to prevent the service from being overrun by a ping attack, where individuals bring down a service by inundating the server with ping requests.

If the service is running, the header is green colored and states that the Service is running. Information on when the service was started, the version of Watson™ Explorer Engine, the build date, ping response, and collections currently served can be found on the Status tab.

Configure the Search Engine Query Service service from the Options tab. You can configure the following items:

  • Port number: TCP port number used by the query service. This port must be larger than 1024, smaller than 49152 and not used by any other well known service. Port numbers starting from 49152 may be randomly allocated by the system and thus cause your query-service to fail to be able to start. The default setting is 7205.
  • Allowed IPs: List of IP addresses (including wildcards) that can access the query-service. The default value for this option is the local loopback address, 127.0.0.1, which limits access to requests from the same system. If you are using multiple front-end systems to distribute or balance incoming queries, access to the query-service must also be enabled for each of those systems.
  • Minimium idle threads: Ensure that there are at least this many threads available to reading HTTP requests. The default setting is 0 threads.
  • Maximum idle threads: Prune threads when there are more than this many idle threads. The default settng is 5 threads.
  • Maximum threads: Absolute maximum number of threads to use for HTTP request handling. While there are more active HTTP threads than this amount, the query-service will stop accepting new connections. A value of 0 will allow any number of requests. The default setting is 0 threads.
  • SSL Certificate: The SSL Certificate file to be use for the query service. If specified, a valid SSL Private Key file must also be specified. Setting the SSL Certificate enables HTTPS access to the query service and disables regular HTTP access.
  • SSL Private Key: The SSL Private Key file that corresponds to the SSL Certificate file specified in the SSL Certificate field. If the SSL Private Key file is encrypted, the SSL Password field must also be specified.
  • SSL Password: The password (entered twice) for the SSL Private Key file. This field is only necessary if the SSL Private Key is encrypted.
Important: The query service SSL options must be specified correctly. An error will be returned if the configuration is invalid or the files specified are damaged or missing. Watson Explorer Engine will exit abnormally if an attempt to start the query service if made with an invalid configuration is made. You can recover from this state by performing the following steps as an administrator:
  1. Forcibly terminate Watson Explorer Engine using the engine-shutdown --forced command (engine-shutdown.exe --forced on Microsoft Windows ) in the bin directory of your installation.
  2. Start Watson Explorer Engine without starting the query service by using the engine-start command (engine-start.exe on Microsoft Windows ) in the bin directory of your installation.
  3. Edit and correct the query service configuration.

To start the Search Engine Query service, got to the Management section of Watson Explorer Engine, and select Services from the left-hand navigation menu. Select the Search Engine tab. On the Status tab, click start to start the service.