Cannot get a connection, pool error Timeout waiting for idle object :sakai

Question

iam using sakai 2.9.1 after a few operations the server stops responding and prints log:-

2014-02-20 12:48:47,085 WARN http-bio-8080-exec-18 org.sakaiproject.db.impl.BasicSqlService - Sql.dbRead: sql: select SAKAI_SITE.SITE_ID,SAKAI_SITE.TITLE,SAKAI_SITE.TYPE,SAKAI_SITE.SHO 
RT_DESC,SAKAI_SITE.DESCRIPTION,SAKAI_SITE.ICON_URL,SAKAI_SITE.INFO_URL,SAKAI_SITE.SKIN,SAKAI_SITE.PUBLISHED,SAKAI_SITE.JOINABLE,SAKAI_SITE.PUBVIEW,SAKAI_SITE.JOIN_ROLE,SAKAI_SITE.IS_SPE
CIAL,SAKAI_SITE.IS_USER,SAKAI_SITE.CREATEDBY,SAKAI_SITE.MODIFIEDBY,SAKAI_SITE.CREATEDON,SAKAI_SITE.MODIFIEDON,SAKAI_SITE.CUSTOM_PAGE_ORDERED,SAKAI_SITE.IS_SOFTLY_DELETED,SAKAI_SITE.SOFT
LY_DELETED_DATE from SAKAI_SITE where ( SITE_ID = ? ) !admin 
org.apache.commons.dbcp.SQLNestedException: Cannot get a connection, pool error Timeout waiting for idle object 
        at org.apache.commons.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:104) 
        at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:880) 
        at org.sakaiproject.db.impl.BasicSqlService.borrowConnection(BasicSqlService.java:260) 
        at org.sakaiproject.db.impl.BasicSqlService.dbRead(BasicSqlService.java:540) 
        at org.sakaiproject.util.BaseDbFlatStorage.getResource(BaseDbFlatStorage.java:341) 
        at org.sakaiproject.util.BaseDbFlatStorage.getResource(BaseDbFlatStorage.java:321) 
        at org.sakaiproject.site.impl.DbSiteService$DbStorage.get(DbSiteService.java:236) 
        at org.sakaiproject.site.impl.BaseSiteService.getDefinedSite(BaseSiteService.java:616) 
        at org.sakaiproject.site.impl.BaseSiteService.getSite(BaseSiteService.java:702) 
        at org.sakaiproject.site.impl.BaseSiteService.getSiteVisit(BaseSiteService.java:780) 
        at org.sakaiproject.site.cover.SiteService.getSiteVisit(SiteService.java:140) 
        at org.sakaiproject.presence.tool.PresenceTool.doGet(PresenceTool.java:141) 
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:621) 
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:722) 
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305) 
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) 
        at org.sakaiproject.util.RequestFilter.doFilter(RequestFilter.java:634) 
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) 
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) 
        at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:684) 
        at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:471) 
        at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:369) 
        at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:329) 
        at org.sakaiproject.tool.impl.ActiveToolComponent$MyActiveTool.forward(ActiveToolComponent.java:511) 
        at org.sakaiproject.portal.charon.SkinnableCharonPortal.forwardTool(SkinnableCharonPortal.java:1470) 
        at org.sakaiproject.portal.charon.handlers.PresenceHandler.doPresence(PresenceHandler.java:140) 
        at org.sakaiproject.portal.charon.handlers.PresenceHandler.doGet(PresenceHandler.java:70) 
        at org.sakaiproject.portal.charon.SkinnableCharonPortal.doGet(SkinnableCharonPortal.java:881) 
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:621) 
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:722) 
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305) 
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) 
        at org.sakaiproject.util.RequestFilter.doFilter(RequestFilter.java:695) 
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) 
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) 
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224) 
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169) 
        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472) 
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168) 
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98) 
        at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927) 
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) 
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407) 
        at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987) 
        at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579) 
        at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:307) 
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) 
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) 
        at java.lang.Thread.run(Thread.java:619) 
Caused by: java.util.NoSuchElementException: Timeout waiting for idle object 
        at org.apache.commons.pool.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:1167) 
        at org.apache.commons.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:96)

Looks like you are not returning connections to the pool (i.e. connection.close() is not called after a connection was used). That would explain why the pool is unable to get a 'free' connection (indicated by "Timeout waiting for idle object"). — vanOekel, Feb 22 '14 at 13:42
Sakai does return connections to the pool and has done so for years. This is an area which has had a fair bit of work and testing done over the years. — Aaron Zeckoski, Jun 10 '14 at 22:29
Could you provide the server thread max count versus the database max connection count you used? — ledlogic, Jan 17 '15 at 17:53

Aaron Zeckoski · Accepted Answer · 2014-06-10T22:27:48.750

You probably need to increase the size of your connection pool. You may need to also adjust the DBMS settings for your database. Here are the settings which you would put into your Sakai configuration file (typically sakai.properties) to control the database pooling.

# The initial number of connections that are created when the pool is started
initialSize@javax.sql.BaseDataSource=10
# The maximum number of active connections that can be allocated from this pool at the same time, or zero for no limit.
maxActive@javax.sql.BaseDataSource=50
# The maximum number of active connections that can remain idle in the pool, without extra ones being released, or zero for no limit.
maxIdle@javax.sql.BaseDataSource=5
# The minimum number of active connections that can remain idle in the pool, without extra ones being created, or 0 to create none.
minIdle@javax.sql.BaseDataSource=5

Cannot get a connection, pool error Timeout waiting for idle object :sakai

1 Answers1