From b0006b6ea2357572637b0c7946dfd074cfe18178 Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@redhat.com>
Date: Fri, 4 Feb 2011 22:44:31 +0100
Subject: [PATCH] new: read db_files and db_subdirs only if mtime changed
The db_files and db_subdirs are unnecessary for unchanged directories.
maildir with 10000 e-mails:
old version:
$ time ./notmuch new
No new mail.
real 0m0.053s
user 0m0.028s
sys 0m0.026s
new version:
$ time ./notmuch new
No new mail.
real 0m0.032s
user 0m0.009s
sys 0m0.023s
Signed-off-by: Karel Zak <kzak@redhat.com>
Reviewed-by: Austin Clements <amdragon@mit.edu>
Looks good (faster than, but provably equivalent to the original code!
notmuch_directory_get_child_* are side-effect free,
db_files/db_subdirs aren't used between where they were set in the old
code and where they are set in the new code, and db_files/db_subdirs
are initialized to NULL when declared).
Another timing data point:
Old code: ./notmuch new 0.77s user 0.28s system 99% cpu 1.051 total
New code: ./notmuch new 0.09s user 0.27s system 98% cpu 0.368 total
---
notmuch-new.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)
diff --git a/notmuch-new.c b/notmuch-new.c
index 941f9d61..31d45532 100644
--- a/notmuch-new.c
+++ b/notmuch-new.c
@@ -247,15 +247,7 @@ add_files_recursive (notmuch_database_t *notmuch,
directory = notmuch_database_get_directory (notmuch, path);
db_mtime = notmuch_directory_get_mtime (directory);
- if (db_mtime == 0) {
- new_directory = TRUE;
- db_files = NULL;
- db_subdirs = NULL;
- } else {
- new_directory = FALSE;
- db_files = notmuch_directory_get_child_files (directory);
- db_subdirs = notmuch_directory_get_child_directories (directory);
- }
+ new_directory = db_mtime ? FALSE : TRUE;
/* If the database knows about this directory, then we sort based
* on strcmp to match the database sorting. Otherwise, we can do
@@ -328,6 +320,11 @@ add_files_recursive (notmuch_database_t *notmuch,
if (fs_mtime == db_mtime)
goto DONE;
+ if (!new_directory) {
+ db_files = notmuch_directory_get_child_files (directory);
+ db_subdirs = notmuch_directory_get_child_directories (directory);
+ }
+
/* Pass 2: Scan for new files, removed files, and removed directories. */
for (i = 0; i < num_fs_entries; i++)
{
--
2.45.2