Hi Greg,
On 8/6/21 12:10 AM, Greg Banks wrote:
The following changes since commit fbe71b1b79e72be3b9afc44b5d479e7fd84b598a:
ioctl_tty.2: wfix (2021-07-26 01:31:54 +0200)
are available in the Git repository at:
git@xxxxxxxxxx:gnb/man-pages.git nscd.conf.5.v4
for you to fetch changes up to 2cb4e042b6aee518f1673d8897fd06056bd87767:
nscd.conf.5: describe reloading, clarifications, v4 (2021-08-05 15:07:20 -0700)
Thanks for the research and the patch!
Please see some comments below.
Thanks,
Alex
----------------------------------------------------------------
Greg Banks (1):
nscd.conf.5: describe reloading, clarifications, v4
man5/nscd.conf.5 | 112 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 109 insertions(+), 3 deletions(-)
diff --git a/man5/nscd.conf.5 b/man5/nscd.conf.5
index 7356bf7c2..9635922fd 100644
--- a/man5/nscd.conf.5
+++ b/man5/nscd.conf.5
@@ -1,5 +1,6 @@
.\" Copyright (c) 1999, 2000 SuSE GmbH Nuernberg, Germany
.\" Author: Thorsten Kukuk <kukuk@xxxxxxx>
+.\" Updates: Greg Banks <gbanks@xxxxxxxxxxxx> Copyright (c) 2021 Microsoft Corp.
.\"
.\" %%%LICENSE_START(GPLv2+_SW_3_PARA)
.\" This program is free software; you can redistribute it and/or
@@ -53,9 +54,12 @@ The default is 0.
.B threads
.I number
.RS
-This is the number of threads that are started to wait for
+This is the initial number of threads that are started to wait for
requests.
At least five threads will always be created.
+The number of threads may increase dynamically up to
+.B max\-threads
+in response to demand from clients, but never decreases.
.RE
.PP
.B max\-threads
@@ -83,9 +87,20 @@ Specifies the user who is allowed to request statistics.
unlimited |
.I number
.RS
-Limit on the number of times a cached entry gets reloaded without being used
+Sets a limit on the number of times a cached entry
+gets reloaded without being used
before it gets removed.
-The default is 5.
+The limit can take values ranging from 0 to 254;
+values 255 or higher behave the same as
+.BR unlimited .
+Limit values can be specified in either decimal
+or hexadecimal with a "0x" prefix.
Only decimal or hexadecimal?
From what you say above that values greater than 255 behave
equivalently to 255, and also this, I suspect this is being parsed with
strtoul(), and they also accept octal with 0... notation.
Also, I guess this behavior is common to all numeric values, so maybe
it's a better idea to put it in a common paragraph (if you know for sure
that this is the case).
+The special value
+.B unlimited
+is case-insensitive.
+The default limit is 5.
+A limit of 0 turns off the reloading feature.
+See NOTES below for further discussion of reloading.
Apart from the comment above, I applied some minor formatting fixes to
your text (see below; whitespace, punctuation, and a typo); could you
include them in your next revision?
Thanks,
Alex
diff --git a/man5/nscd.conf.5 b/man5/nscd.conf.5
index 9635922fd..7534b77e6 100644
--- a/man5/nscd.conf.5
+++ b/man5/nscd.conf.5
@@ -59,7 +59,8 @@ requests.
At least five threads will always be created.
The number of threads may increase dynamically up to
.B max\-threads
-in response to demand from clients, but never decreases.
+in response to demand from clients,
+but never decreases.
.RE
.PP
.B max\-threads
@@ -259,7 +260,8 @@ The default values used in the configuration file of
your distribution might differ.
.SS Reloading
.BR nscd (8)
-has a feature called reloading whose behavior can be surprising.
+has a feature called reloading,
+whose behavior can be surprising.
.PP
Reloading is enabled when the
.B reload-count
@@ -270,10 +272,11 @@ although your distribution may differ.
When reloading is enabled,
positive cached entries (the results of successful queries)
do not simply expire when their TTL is up.
-Instead, at the expiry time
+Instead, at the expiry time,
.B nscd
will "reload",
-i.e., re-issue to the name service the same query that created the
cached entry,
+i.e.,
+re-issue to the name service the same query that created the cached entry,
to get a new value to cache.
Depending on
.I /etc/nsswitch.conf
@@ -284,20 +287,20 @@ until
.B reload-count
reloads have happened for the entry,
and only then will it actually be removed from the cache.
-A request from a client which hits the entry will reset the
-reload counter on the entry.
+A request from a client which hits the entry will
+reset the reload counter on the entry.
Purging the cache using
.I nscd\~-i
overrides the reload logic and removes the entry.
.PP
-Reloading has the effect of extending cache entry TTLs without
-compromising on cache coherency,
+Reloading has the effect of extending cache entry TTLs
+without compromising on cache coherency,
at the cost of additional load on the backing name service.
Whether this is a good idea on your system depends on
details of your applications' behavior,
your name service,
and the effective TTL values of your cache entries.
Note that for some name services
(for example, DNS),
the effective TTL is the value returned from the name service and
.I not
@@ -308,7 +311,7 @@ attribute.
Please consider the following advice carefully:
.IP \(bu
If your application will make a second request for the same name,
-after more then 1 TTL but before
+after more than 1 TTL but before
.B reload\-count
TTLs,
and is sensitive to the latency of a cache miss,
@@ -330,8 +333,8 @@ Setting
to
.B unlimited
is almost never a good idea,
-as it will result in a cache that never expires entries and puts
never-ending
-additional load on the backing name service.
+as it will result in a cache that never expires entries
+and puts never-ending additional load on the backing name service.
.PP
Some distributions have an init script for
.BR nscd (8)
--
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/
