From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Shawn O. Pearce" Subject: [JGIT PATCH 5/9] Arrange pack files in recency order to improve quick hits Date: Wed, 11 Feb 2009 18:36:55 -0800 Message-ID: <1234406219-19547-6-git-send-email-spearce@spearce.org> References: <1234406219-19547-1-git-send-email-spearce@spearce.org> <1234406219-19547-2-git-send-email-spearce@spearce.org> <1234406219-19547-3-git-send-email-spearce@spearce.org> <1234406219-19547-4-git-send-email-spearce@spearce.org> <1234406219-19547-5-git-send-email-spearce@spearce.org> Cc: git@vger.kernel.org To: Robin Rosenberg X-From: git-owner@vger.kernel.org Thu Feb 12 03:39:03 2009 Return-path: Envelope-to: gcvg-git-2@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by lo.gmane.org with esmtp (Exim 4.50) id 1LXRTg-0002tJ-FP for gcvg-git-2@gmane.org; Thu, 12 Feb 2009 03:39:00 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758324AbZBLCha (ORCPT ); Wed, 11 Feb 2009 21:37:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756786AbZBLCh3 (ORCPT ); Wed, 11 Feb 2009 21:37:29 -0500 Received: from george.spearce.org ([209.20.77.23]:39183 "EHLO george.spearce.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755993AbZBLChE (ORCPT ); Wed, 11 Feb 2009 21:37:04 -0500 Received: by george.spearce.org (Postfix, from userid 1000) id C060D38221; Thu, 12 Feb 2009 02:37:03 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.2.4 (2008-01-01) on george.spearce.org X-Spam-Level: X-Spam-Status: No, score=-4.4 required=4.0 tests=ALL_TRUSTED,BAYES_00 autolearn=ham version=3.2.4 Received: from localhost.localdomain (localhost [127.0.0.1]) by george.spearce.org (Postfix) with ESMTP id 9761D38222; Thu, 12 Feb 2009 02:37:01 +0000 (UTC) X-Mailer: git-send-email 1.6.2.rc0.204.gf6b427 In-Reply-To: <1234406219-19547-5-git-send-email-spearce@spearce.org> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Packs with newer modification dates are more likely to contain data related to recent commits, and thus will have a better probability of containing an object we care about when we are looking only at recent history. In some cases, this may permit JGit to avoid reading a very large historical pack's index file into memory if the only data we ever need is available in newer pack files. Signed-off-by: Shawn O. Pearce --- .../src/org/spearce/jgit/lib/PackFile.java | 11 +++++++++++ .../src/org/spearce/jgit/lib/Repository.java | 1 + 2 files changed, 12 insertions(+), 0 deletions(-) diff --git a/org.spearce.jgit/src/org/spearce/jgit/lib/PackFile.java b/org.spearce.jgit/src/org/spearce/jgit/lib/PackFile.java index 3542560..7a16bf7 100644 --- a/org.spearce.jgit/src/org/spearce/jgit/lib/PackFile.java +++ b/org.spearce.jgit/src/org/spearce/jgit/lib/PackFile.java @@ -43,6 +43,7 @@ import java.io.IOException; import java.io.OutputStream; import java.util.Collections; +import java.util.Comparator; import java.util.Iterator; import java.util.zip.CRC32; import java.util.zip.CheckedOutputStream; @@ -57,10 +58,19 @@ * objects are similar. */ public class PackFile implements Iterable { + /** Sorts PackFiles to be most recently created to least recently created. */ + public static Comparator SORT = new Comparator() { + public int compare(final PackFile a, final PackFile b) { + return b.packLastModified - a.packLastModified; + } + }; + private final File idxFile; private final WindowedFile pack; + private int packLastModified; + private PackIndex loadedIdx; private PackReverseIndex reverseIdx; @@ -75,6 +85,7 @@ */ public PackFile(final File idxFile, final File packFile) { this.idxFile = idxFile; + this.packLastModified = (int) (packFile.lastModified() >> 10); pack = new WindowedFile(packFile) { @Override protected void onOpen() throws IOException { diff --git a/org.spearce.jgit/src/org/spearce/jgit/lib/Repository.java b/org.spearce.jgit/src/org/spearce/jgit/lib/Repository.java index b9c7b2e..96c62df 100644 --- a/org.spearce.jgit/src/org/spearce/jgit/lib/Repository.java +++ b/org.spearce.jgit/src/org/spearce/jgit/lib/Repository.java @@ -823,6 +823,7 @@ public void scanForPacks() { scanForPacks(new File(d, "pack"), p); final PackFile[] arr = new PackFile[p.size()]; p.toArray(arr); + Arrays.sort(arr, PackFile.SORT); synchronized (this) { packFileList = arr; } -- 1.6.2.rc0.204.gf6b427