<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body>
<p>I'm not a consumer of this and agree that it's up to users to
speak up, so I'll stop here - with one final observation.</p>
<p>The issue comment containing the benchmarks includes:</p>
<p>
<blockquote type="cite">Speedup provided by the <code>map</code>
format does not seem significant enough to warrant the
complexity of map format, especially when we take into account
that the difference measured in terms of "real time" is in order
of 10s of seconds.</blockquote>
10s of seconds <b>per zone</b> can certainly add up. Call it 10
secs/zone * 100,000 zones = 1M sec / 3600 = 278 hrs <b>saved</b>.</p>
<p>Suppose loading zones is not disk limited, and cores scale
linearly (e.g. no lock conflicts & an index lets each core
find a zone to work on for free). So give it 16 cores (each
taking on one complete zone), and it's still 17 hrs saved. Real
life won't be that efficient - meaning cores won't help that much.<br>
</p>
<p>A new memory mapped data structure that didn't require "updating
node pointers" (e.g. that used offsets instead of pointers) may be
worth considering. In current hardware and with a decent compiler
and coding, the apparent cost of this over absolute pointers may
well be vanishingly small.</p>
<p>OK, that was two.<br>
</p>
<pre class="moz-signature" cols="72">Timothe Litt
ACM Distinguished Engineer
--------------------------
This communication may not represent the ACM or my employer's views,
if any, on the matters discussed.
</pre>
<div class="moz-cite-prefix">On 10-Sep-21 12:56, Victoria Risk
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:E9F8234F-FD6E-4378-83E7-54929CB4C248@isc.org">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<br class="">
<div>
<blockquote type="cite" class="">
<div class="">
<div class="content-isolator__container">
<div class="">
<blockquote type="cite"
cite="mid:0CC54D4B-7F9B-49B0-AC20-467874716C2B@isc.org"
class="">
<div class="">
<blockquote type="cite" class="">
<div class="">
<div class="content-isolator__container">
<div class="">After all the "other
improvements in performance" that you cited,
what is the performance difference between
map and the other formats? </div>
</div>
</div>
</blockquote>
<div class=""><br class="">
</div>
I don’t know that, to be honest. We don’t have the
resources to benchmark everything. Maybe someone on
this list could? We would also like to be able to
embark on a wholesale update to the rbtdb next year
and this is the sort of thing that might complicate
refactoring unnecessarily. <br class="">
</div>
</blockquote>
</div>
</div>
</div>
</blockquote>
<br class="">
</div>
<div><br class="">
</div>
<div>I was wrong, and in fact we have benchmarked it. See <a
href="https://gitlab.isc.org/isc-projects/bind9/-/issues/2882"
class="" moz-do-not-send="true">https://gitlab.isc.org/isc-projects/bind9/-/issues/2882</a> for
details. Map format is still faster than raw, but not so much
faster that it warrants retaining it, given it is riskier,
harder to maintain and we have no feedback from users that it is
important to them. It also seems not to work with large numbers
of zones, (>100K) at least in current versions of 9.11 and
9.16, which is further indication that it isn’t in wide use or
we would have had complaints. </div>
<div><br class="">
</div>
<div>We also have discussed internally that there are other
factors, other than loading the zone files, that may have more
impact on the time it takes a BIND server to restart.</div>
<br class="">
<div class="">If anyone out there is using it successfully, and
wants us to keep this feature, this would be the time to speak
up!</div>
<div class=""><br class="">
</div>
<div class="">Thank you,</div>
<div class=""><br class="">
</div>
<div class="">Vicky</div>
</blockquote>
</body>
</html>