[lttng-dev] RFC Streaming and reading traces over the network

Julien Desfossez jdesfossez at efficios.com
Thu Mar 29 12:00:24 EDT 2012


On 27/03/12 06:10 AM, Stefan Hajnoczi wrote:
> On Mon, Mar 26, 2012 at 1:27 PM, Julien Desfossez
> <jdesfossez at efficios.com> wrote:
>> - indexes are sent over the control data connection
> 
> What exactly is an index?  I guess it's a lookup data structure that
> tells you where in the trace data to start reading?
> 
> Sorry if this is outside the scope of network streaming, maybe this is
> basic Babeltrace/CTF background knowledge that I missed.

Indeed the index is a concept in babeltrace, I should have mentionned it.
When you open a trace with Babeltrace (or with the API), before printing
the trace it generates an index in memory in order to have a mapping
between the trace packets and their position in the trace files.

I hope it makes this proposal clearer.

Julien



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