at com.atlassian.confluence.mail.jobs.DailyReportJob.doExecute performs poorly with a large number of spaces/pages

@40000000494b3cf90820e8e4 "DefaultQuartzScheduler_Worker-1" prio=10 tid=0x2a158c00 nid=0x5676 runnable [0x29996000..0x29996e20]
@40000000494b3cf90820f0b4    java.lang.Thread.State: RUNNABLE
@40000000494b3cf908211bac 	at net.sf.hibernate.util.IdentityMap.entryList(IdentityMap.java:175)
@40000000494b3cf9082146a4 	at net.sf.hibernate.util.IdentityMap.entries(IdentityMap.java:58)
@40000000494b3cf908217d54 	at net.sf.hibernate.impl.SessionImpl.flushCollections(SessionImpl.java:2824)
@40000000494b3cf90821b01c 	at net.sf.hibernate.impl.SessionImpl.flushEverything(SessionImpl.java:2282)
@40000000494b3cf90821b7ec 	at net.sf.hibernate.impl.SessionImpl.flush(SessionImpl.java:2260)
@40000000494b3cf90821fe3c 	at net.sf.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:61)
@40000000494b3cf90822060c 	at org.springframework.orm.hibernate.HibernateTransactionManager.doCommit(HibernateTransactionManager.java:510)
@40000000494b3cf9082234ec 	at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:662)
@40000000494b3cf908223cbc 	at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:632)
@40000000494b3cf9082267b4 	at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:314)
@40000000494b3cf90822736c 	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:116)
@40000000494b3cf90822cd44 	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
@40000000494b3cf90822d514 	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
@40000000494b3cf90822dce4 	at $Proxy28.isSuperUser(Unknown Source)
@40000000494b3cf9082307dc 	at com.atlassian.confluence.util.GeneralUtil.isSuperUser(GeneralUtil.java:900)
@40000000494b3cf908230fac 	at com.atlassian.confluence.mail.ChangeDigestNotificationBean.userHasAccessTo(ChangeDigestNotificationBean.java:180)
@40000000494b3cf908233aa4 	at com.atlassian.confluence.mail.ChangeDigestNotificationBean.getAllChangeReportForUser(ChangeDigestNotificationBean.java:81)
@40000000494b3cf908234274 	at com.atlassian.confluence.mail.ChangeDigestNotificationBean.getAllChangeReports(ChangeDigestNotificationBean.java:168)
@40000000494b3cf908237154 	at com.atlassian.confluence.mail.jobs.DailyReportJob.doExecute(DailyReportJob.java:59)
@40000000494b3cf90823753c 	at com.atlassian.quartz.jobs.AbstractJob.executeInternal(AbstractJob.java:87)
@40000000494b3cf90823a41c 	at org.springframework.scheduling.quartz.QuartzJobBean.execute(QuartzJobBean.java:86)
@40000000494b3cf90823abec 	at com.atlassian.confluence.setup.quartz.DelegatingClusterAwareQuartzJobBean.executeJob(DelegatingClusterAwareQuartzJobBean.java:16)
@40000000494b3cf90823d6e4 	at com.atlassian.confluence.setup.quartz.AbstractClusterAwareQuartzJobBean.surroundJobExecutionWithLogging(AbstractClusterAwareQuartzJobBean.java:64)
@40000000494b3cf90823e29c 	at com.atlassian.confluence.setup.quartz.AbstractClusterAwareQuartzJobBean.executeInternal(AbstractClusterAwareQuartzJobBean.java:47)
@40000000494b3cf908240d94 	at org.springframework.scheduling.quartz.QuartzJobBean.execute(QuartzJobBean.java:86)
@40000000494b3cf908241564 	at org.quartz.core.JobRunShell.run(JobRunShell.java:203)
@40000000494b3cf90824405c 	at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:520)