From 741ec30d6da1d2bb94b9b6f8884fdff87bec1656 Mon Sep 17 00:00:00 2001 From: Austin Clements Date: Fri, 25 Oct 2013 16:33:42 +2000 Subject: [PATCH] [PATCH] new: Don't scan unchanged directories with no sub-directories --- 6d/b9fb36046010c6fbd2764c51f456d14fb45816 | 110 ++++++++++++++++++++++ 1 file changed, 110 insertions(+) create mode 100644 6d/b9fb36046010c6fbd2764c51f456d14fb45816 diff --git a/6d/b9fb36046010c6fbd2764c51f456d14fb45816 b/6d/b9fb36046010c6fbd2764c51f456d14fb45816 new file mode 100644 index 000000000..fbac8b0b3 --- /dev/null +++ b/6d/b9fb36046010c6fbd2764c51f456d14fb45816 @@ -0,0 +1,110 @@ +Return-Path: +X-Original-To: notmuch@notmuchmail.org +Delivered-To: notmuch@notmuchmail.org +Received: from localhost (localhost [127.0.0.1]) + by olra.theworths.org (Postfix) with ESMTP id EC2F9431FBD + for ; Thu, 24 Oct 2013 13:33:54 -0700 (PDT) +X-Virus-Scanned: Debian amavisd-new at olra.theworths.org +X-Spam-Flag: NO +X-Spam-Score: -0.7 +X-Spam-Level: +X-Spam-Status: No, score=-0.7 tagged_above=-999 required=5 + tests=[RCVD_IN_DNSWL_LOW=-0.7] autolearn=disabled +Received: from olra.theworths.org ([127.0.0.1]) + by localhost (olra.theworths.org [127.0.0.1]) (amavisd-new, port 10024) + with ESMTP id 252tNtMlqSzj for ; + Thu, 24 Oct 2013 13:33:48 -0700 (PDT) +Received: from dmz-mailsec-scanner-4.mit.edu (dmz-mailsec-scanner-4.mit.edu + [18.9.25.15]) + by olra.theworths.org (Postfix) with ESMTP id A28E8431FBC + for ; Thu, 24 Oct 2013 13:33:48 -0700 (PDT) +X-AuditID: 1209190f-b7fa08e0000009c6-5d-5269842c51d6 +Received: from mailhub-auth-4.mit.edu ( [18.7.62.39]) + by dmz-mailsec-scanner-4.mit.edu (Symantec Messaging Gateway) with SMTP + id 40.D7.02502.C2489625; Thu, 24 Oct 2013 16:33:48 -0400 (EDT) +Received: from outgoing.mit.edu (outgoing-auth-1.mit.edu [18.9.28.11]) + by mailhub-auth-4.mit.edu (8.13.8/8.9.2) with ESMTP id r9OKXjG9030310; + Thu, 24 Oct 2013 16:33:46 -0400 +Received: from drake.dyndns.org (26-4-172.dynamic.csail.mit.edu [18.26.4.172]) + (authenticated bits=0) + (User authenticated as amdragon@ATHENA.MIT.EDU) + by outgoing.mit.edu (8.13.8/8.12.4) with ESMTP id r9OKXhnO016620 + (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=NOT); + Thu, 24 Oct 2013 16:33:45 -0400 +Received: from amthrax by drake.dyndns.org with local (Exim 4.77) + (envelope-from ) + id 1VZRbD-0006Oz-U8; Thu, 24 Oct 2013 16:33:43 -0400 +From: Austin Clements +To: notmuch@notmuchmail.org +Subject: [PATCH] new: Don't scan unchanged directories with no sub-directories +Date: Thu, 24 Oct 2013 16:33:42 -0400 +Message-Id: <1382646822-24556-1-git-send-email-amdragon@mit.edu> +X-Mailer: git-send-email 1.8.4.rc3 +X-Brightmail-Tracker: + H4sIAAAAAAAAA+NgFlrMIsWRmVeSWpSXmKPExsUixG6nrqvTkhlkMH87p8X1mzOZLTpu72Zz + YPJ4tuoWs8fHp7dYApiiuGxSUnMyy1KL9O0SuDKafzxjLZjKV9Fy/B9bA+Ndri5GTg4JAROJ + x23zWCBsMYkL99azgdhCAvsYJbYfcuti5AKyNzJK7Pj/kB0icYRJ4tgzJ4jEXEaJT62LwbrZ + BDQktu1fzghiiwhIS+y8O5sVxGYWcJTYc2A5WI2wgJ/E/SkrgeIcHCwCqhJX5vCBhHkFHCSu + tR5kgzhCSWLhqW2sExh5FzAyrGKUTcmt0s1NzMwpTk3WLU5OzMtLLdI10cvNLNFLTSndxAgK + C05J/h2M3w4qHWIU4GBU4uHV+JAeJMSaWFZcmXuIUZKDSUmUd11TZpAQX1J+SmVGYnFGfFFp + TmrxIUYJDmYlEd5pekA53pTEyqrUonyYlDQHi5I4700O+yAhgfTEktTs1NSC1CKYrAwHh5IE + 7w2QoYJFqempFWmZOSUIaSYOTpDhPEDDn4HU8BYXJOYWZ6ZD5E8xKkqJ8/4ESQiAJDJK8+B6 + YXH7ilEc6BVh3n8gVTzAmIfrfgU0mAlo8JQlaSCDSxIRUlINjIHzNLe++KZvH3f4ssqzHxt2 + CO0puR7aKJWqaqcruuPxpV4uA40E/tuvGbZbFt2cdnC9y+2FD3ojSoVWTHMr0zw6f3NB1sTO + RaGMLIs7TvUJGIsen1e6Ivv+v30f1dK4M87pzuY/YsAUzidVsYlvnmyEk37hkZJpExQcu39a + zuyWqf2xrjLtoxJLcUaioRZzUXEiAB53vU+2AgAA +X-BeenThere: notmuch@notmuchmail.org +X-Mailman-Version: 2.1.13 +Precedence: list +List-Id: "Use and development of the notmuch mail system." + +List-Unsubscribe: , + +List-Archive: +List-Post: +List-Help: +List-Subscribe: , + +X-List-Received-Date: Thu, 24 Oct 2013 20:33:55 -0000 + +This can substantially reduce the cost of notmuch new in some +situations, such as when the file system cache is cold or when the +Maildir is on NFS. +--- + notmuch-new.c | 20 ++++++++++++++++++++ + 1 file changed, 20 insertions(+) + +diff --git a/notmuch-new.c b/notmuch-new.c +index faa33f1..364c73a 100644 +--- a/notmuch-new.c ++++ b/notmuch-new.c +@@ -323,6 +323,26 @@ add_files (notmuch_database_t *notmuch, + } + db_mtime = directory ? notmuch_directory_get_mtime (directory) : 0; + ++ /* If the directory is unchanged from our last scan and has no ++ * sub-directories, then return without scanning it at all. In ++ * some situations, skipping the scan can substantially reduce the ++ * cost of notmuch new, especially since the huge numbers of files ++ * in Maildirs make scans expensive, but all files live in leaf ++ * directories. ++ * ++ * To check for sub-directories, we borrow a trick from find, ++ * kpathsea, and many other UNIX tools: since a directory's link ++ * count is the number of sub-directories (specifically, their ++ * '..' entries) plus 2 (the link from the parent and the link for ++ * '.'). This check is safe even on weird file systems, since ++ * file systems that can't compute this will return 0 or 1. This ++ * is safe even on *really* weird file systems like HFS+ that ++ * mistakenly return the total number of directory entries, since ++ * that only inflates the count beyond 2. ++ */ ++ if (directory && fs_mtime == db_mtime && st.st_nlink == 2) ++ goto DONE; ++ + /* If the database knows about this directory, then we sort based + * on strcmp to match the database sorting. Otherwise, we can do + * inode-based sorting for faster filesystem operation. */ +-- +1.8.4.rc3 + -- 2.26.2