Attached patch adds a simple call to posix_fadvise with
POSIX_FADV_DONTNEED on all the files being read when doing a base
backup, to help the kernel not to trash the filesystem cache.
Seems like a simple enough fix - in fact, I don't remember why I took
it out of the original patch :O
Any reason not to put this in? Is it even safe enough to put into 9.1
(probably not, but maybe?)
--
Magnus Hagander
Me: http://www.hagander.net/
Work: http://www.redpill-linpro.com/
diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index 4841095..54c4d13 100644
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -781,6 +781,15 @@ sendFile(char *readfilename, char *tarfilename, struct stat * statbuf)
pq_putmessage('d', buf, pad);
}
+ /*
+ * If we have posix_fadvise(), send a note to the kernel that we are not
+ * going to need this data anytime soon, so that it can be discarded
+ * from the filesystem cache.
+ */
+#if defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_DONTNEED)
+ (void) posix_fadvise(fileno(fp), 0, 0, POSIX_FADV_DONTNEED);
+#endif
+
FreeFile(fp);
}
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
