From e3fc1efbef3fe96c2b2a274078a4e02c338d4e9f Mon Sep 17 00:00:00 2001 From: orbiter Date: Wed, 3 Aug 2011 18:47:43 +0000 Subject: [PATCH] performance hack and ensuring termination in serverAccessTracker. cause: "Session_:53600#0_POST /yacy/hello.html HTTP/1.1" prio=10 tid=0x2322b000 nid=0x3ba7 runnable [0x03d3e000] java.lang.Thread.State: RUNNABLE at java.lang.Long.valueOf(Long.java:557) at de.anomic.server.serverAccessTracker.clearTooOldAccess(serverAccessTracker.java:113) at de.anomic.server.serverAccessTracker.cleanupAccessTracker(serverAccessTracker.java:75) - locked <0x3bda2ae8> (a de.anomic.server.serverAccessTracker) at de.anomic.server.serverAccessTracker.track(serverAccessTracker.java:125) at de.anomic.server.serverSwitch.track(serverSwitch.java:542) at de.anomic.http.server.HTTPDemon.parseRequestLine(HTTPDemon.java:641) at de.anomic.http.server.HTTPDemon.POST(HTTPDemon.java:491) at sun.reflect.GeneratedMethodAccessor13.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at de.anomic.server.serverCore$Session.listen(serverCore.java:757) at de.anomic.server.serverCore$Session.run(serverCore.java:651) git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@7862 6c8d7289-2bf4-0310-a012-ef5d649a1542 --- .../de/anomic/server/serverAccessTracker.java | 67 ++++++++++--------- 1 file changed, 34 insertions(+), 33 deletions(-) diff --git a/source/de/anomic/server/serverAccessTracker.java b/source/de/anomic/server/serverAccessTracker.java index a5cd24f80..8c37c3236 100644 --- a/source/de/anomic/server/serverAccessTracker.java +++ b/source/de/anomic/server/serverAccessTracker.java @@ -30,17 +30,17 @@ import java.util.concurrent.ConcurrentLinkedQueue; public class serverAccessTracker { private static final long cleanupCycle = 60000; // 1 minute - + private final long maxTrackingTime; private final int maxTrackingCount; private final int maxHostCount; private final ConcurrentHashMap> accessTracker; // mappings from requesting host to an ArrayList of serverTrack-entries private long lastCleanup; - + public static class Track { - private long time; - private String path; - public Track(long time, String path) { + private final long time; + private final String path; + public Track(final long time, final String path) { this.time = time; this.path = path; } @@ -51,14 +51,14 @@ public class serverAccessTracker { return this.path; } } - - public serverAccessTracker(long maxTrackingTime, int maxTrackingCount, int maxTrackingHostCount) { + + public serverAccessTracker(final long maxTrackingTime, final int maxTrackingCount, final int maxTrackingHostCount) { this.maxTrackingTime = maxTrackingTime; this.maxTrackingCount = maxTrackingCount; this.maxHostCount = maxTrackingHostCount; this.accessTracker = new ConcurrentHashMap>(); } - + /* * remove all entries from the access tracker where the age of the last access is greater than the given timeout */ @@ -66,9 +66,9 @@ public class serverAccessTracker { if (System.currentTimeMillis() - this.lastCleanup < cleanupCycle) return; // avoid too many scans of the queues this.lastCleanup = System.currentTimeMillis(); - + // clear entries which had no entry for the maxTrackingTime time - final Iterator>> i = accessTracker.entrySet().iterator(); + final Iterator>> i = this.accessTracker.entrySet().iterator(); ConcurrentLinkedQueue track; while (i.hasNext()) { track = i.next().getValue(); @@ -81,16 +81,16 @@ public class serverAccessTracker { while (track.size() > this.maxTrackingCount) try { // delete the oldest entries track.remove(); - } catch (NoSuchElementException e) { break; } // concurrency may cause that the track is already empty + } catch (final NoSuchElementException e) { break; } // concurrency may cause that the track is already empty } } - + // if there are more entries left than maxTrackingCount, delete some. - while (accessTracker.size() > this.maxHostCount) { + while (this.accessTracker.size() > this.maxHostCount) { // delete just any - String key = accessTracker.keys().nextElement(); + final String key = this.accessTracker.keys().nextElement(); if (key == null) break; // may occur because of concurrency effects - accessTracker.remove(key); + this.accessTracker.remove(key); } } @@ -100,62 +100,63 @@ public class serverAccessTracker { * @param delta the time delta from now to the past where the access times shall be computed * @return the number of accesses to the host in the given time span */ - public int latestAccessCount(final String host, long delta) { - Collection timeList = accessTrack(host); + public int latestAccessCount(final String host, final long delta) { + final Collection timeList = accessTrack(host); if (timeList == null) return 0; - long time = System.currentTimeMillis() - delta; + final long time = System.currentTimeMillis() - delta; int c = 0; - for (Track l: timeList) if ( l != null && l.getTime() > time) c++; + for (final Track l: timeList) if ( l != null && l.getTime() > time) c++; return c; } - + private void clearTooOldAccess(final ConcurrentLinkedQueue access) { - Long time = Long.valueOf(System.currentTimeMillis() - maxTrackingTime); - Iterator e = access.iterator(); + final long time = System.currentTimeMillis() - this.maxTrackingTime; + final Iterator e = access.iterator(); Track l; - while (e.hasNext()) { + int max = access.size(); // ensure termination + while (e.hasNext() && max-- > 0) { l = e.next(); if (l.getTime() <= time) e.remove(); } } - + public void track(final String host, String accessPath) { // check storage size if (System.currentTimeMillis() - this.lastCleanup > cleanupCycle) { cleanupAccessTracker(); } - + // learn that a specific host has accessed a specific path if (accessPath == null) accessPath="NULL"; - ConcurrentLinkedQueue track = accessTracker.get(host); + ConcurrentLinkedQueue track = this.accessTracker.get(host); if (track == null) { track = new ConcurrentLinkedQueue(); track.add(new Track(System.currentTimeMillis(), accessPath)); // add to tracker - accessTracker.put(host, track); + this.accessTracker.put(host, track); } else { track.add(new Track(System.currentTimeMillis(), accessPath)); clearTooOldAccess(track); } } - + public Collection accessTrack(final String host) { // returns mapping from Long(accesstime) to path - - ConcurrentLinkedQueue access = accessTracker.get(host); + + final ConcurrentLinkedQueue access = this.accessTracker.get(host); if (access == null) return null; // clear too old entries clearTooOldAccess(access); if (access.isEmpty()) { - accessTracker.remove(host); + this.accessTracker.remove(host); } return access; } - + public Iterator accessHosts() { // returns an iterator of hosts in tracker (String) final Map> accessTrackerClone = new ConcurrentHashMap>(); - accessTrackerClone.putAll(accessTracker); + accessTrackerClone.putAll(this.accessTracker); return accessTrackerClone.keySet().iterator(); } }