[Koha-devel] Re: [Koha-zebra] zebra config problem (still 0, yes, really 0 !)

[Mike Taylor]

> Date: Thu, 09 Feb 2006 13:25:50 -0500
> From: Sebastian Hammer <address@hidden>
>
>> I flatly refuse to believe that the communication layer is
>> responsible for a slow-down by a factor of 16, so something else is
>> going on here.  My best guess is that "zebraidx update" is making
>> use of caching mechanisms that ZOOM's update requests are not
>> benefiting from.  There may be a way to have ZOOM request that
>> caching: Adam will be able to tell us.
>
> I don't particularly refuse to believe the factor 16. Network
> overheads are very expensive.

C'mon, dude.  We're adding and indexing records here.  A typical MARC
record might contain say 30 indexable words, so naively you're doing
30 seeks and writes.  Suppose caching reduces that by a factor of
ten.  Still -- you're seeking and writing multiple times.  No
in-memory copy (which is all the TCP/IP socket write is) is going to
come close to using that much time.  As always we should benchmark
this rather than just spouting opinions, but I bet you 422 trillion
Canadian dollars that switching to a Unix-domain socket makes very
little difference indeed.

(If the client and server were on different machines, I would be less
disinclined to swallow your hypothesis.)

> I think you're only transfering one record at a time, right? That's
> bad for network latency in itself, but I dunno if either the client
> API or the server will let us do more at a time.. it might be worth
> considering, because adding more records at a time is generally a
> lot faster (per record) than adding single records.

Yes, this would be a reasonable enhancement to make to our update API.

> One thing to try, if you don't already do it, is to use a UNIX domain 
> socket if your server and client run on the same site.. 
> 
> zebrasrv unix:s
> 
> Will listen on a socket called 's'... since Unix Domain sockets
> circumvent the network stuff and work just like pipes, they can be
> tons faster... I usually use this when using Zebra as an embedded
> engine. I'm hoping Mike's ZOOM Perl wrapper won't prevent you from
> using this option of the lower-layer tool.

It won't!  Go right ahead, Unix-domain sockets will work fine.

 _/|_    ___________________________________________________________________
/o ) \/  Mike Taylor  <address@hidden>  http://www.miketaylor.org.uk
)_v__/\  "I never make predictions and I never will" -- Paul Gascoigne.