On Mon, 2016-06-13 at 11:23 -0700, Rallavagu wrote: > > On 6/7/16 6:13 AM, Oleg Kalnichevski wrote: > > On Mon, 2016-06-06 at 13:43 -0700, Rallavagu wrote: > >> HttpClient 4.3.2, JDK 7 > >> > >> I was doing something similar to what is talked in this link related to > >> http commons client 3.x > >> > >> http://httpcomponents.10934.n7.nabble.com/quot-Keep-alive-quot-stale-connections-and-socket-reuse-td15315.html > >> > >> I am using PoolingHttpClientConnectionManager with following SocketConfig. > >> > >> SocketConfig socketConfig = > >> SocketConfig.copy(SocketConfig.DEFAULT).setSoKeepAlive(true).setSoReuseAddress(true).build(); > >> > >> From debug logs, I see that connections are maintained in the pool. > >> Here is the snippet from the log. > >> > >> [DEBUG] 06/06/2016 12:58:16 > >> org.apache.http.impl.conn.PoolingHttpClientConnectionManager Connection > >> request: [route: {s}->https://<host>:443][total kept alive: 1; route > >> allocated: 1 of 50; total allocated: 1 of 100] > >> [DEBUG] 06/06/2016 12:58:16 > >> org.apache.http.impl.conn.PoolingHttpClientConnectionManager Connection > >> leased: [id: 2][route: {s}->https://<host>:443][total kept alive: 0; > >> route allocated: 1 of 50; total allocated: 1 of 100] > >> [DEBUG] 06/06/2016 12:58:16 > >> org.apache.http.impl.conn.PoolingHttpClientConnectionManager Connection > >> released: [id: 2][route: {s}->https://<host>:443][total kept alive: 1; > >> route allocated: 1 of 50; total allocated: 1 of 100] > >> > >> What I am noticing is that every time a connection is used (leased) from > >> the pool, a connection is being established (socketConnect) to the > >> server unless requested in quick successions where a connection is > >> detected as "not stale". Snippet from "MainClientExec.java" > >> > >> if (config.isStaleConnectionCheckEnabled()) { > >> // validate connection > >> if (managedConn.isOpen()) { > >> this.log.debug("Stale connection check"); > >> if (managedConn.isStale()) { > >> this.log.debug("Stale connection detected"); > >> managedConn.close(); > >> } > >> } > >> } > >> > >> > >> Using AspectJ, I could track connection opening to the server. > >> > >> [INFO] 06/06/2016 12:58:00 com.test.aop.AbstractLogAspect > >> SSLConnectionSocketFactory.java:232.connectSocket arguments [30000, > >> Socket[addr=<host>/<IP Address>,port=443,localport=49439], > >> https://<host>:443, <host>/<IP Address>:443, null, > >> org.apache.http.client.protocol.HttpClientContext@137f7542] Execution > >> time: 313 > >> > >> The above call is not happening when "managedConn.isStale()" returns false. > >> > >> As you can see, I would like to avoid the "connectSocket" call as it is > >> expensive. Am I right in my assumption that a "keep-alive" connection is > >> supposed to work on an already established socket so it is being reused? > > > > Yes, you are. > > Thanks. I could validate that keep-alive connection works on already > established socket. > > > >> Also, I understand that we can't rely on isStale() method. Any > >> comments/suggestions are welcome. > >> > > > > Please consider upgrading to 4.5.2. Stale connection check logic has > > been reworked in 4.5 > I have upgraded to 4.5.2 and found that "setValidateAfterInactivity" > method could be used to check for stale connections. > > I have a background thread to detect and clear idle/expired connections > from PoolingHttpClientConnectionManager. I wonder how would > "setValidateAfterInactivity" impact that if at all. >
It would not (unless, of course, expiry deadline is less than inactivity period). > I understand that per http/1.1 spec a keep-alive request is assumed to > be "forever" in case server does not respond with keep-alive header. > But, connections are in fact not left open forever (in tomcat, it > defaults to 20 sec; connectionTimeout="20000"). Doesn't it make sense to > set a response header so a client can manage keep-alive connection more > gracefully by sending "Connection: close" when they expire? In the case > of background thread to check expired connections, there won't be any as > server never responded with keep-alive header and connections are marked > to be kept alive forever. Is the only solution is to create a servlet > filter that sets the response header? > Use custom ConnectionKeepAliveStrategy to set a finite keep-alive period by default . Oleg --------------------------------------------------------------------- To unsubscribe, e-mail: httpclient-users-unsubscr...@hc.apache.org For additional commands, e-mail: httpclient-users-h...@hc.apache.org
