1) Kafka byte
offset is separated from hostname by a tab.
This is annoying, but since thus far I
haven't cared about doing any analysis on hostname or byte offset, I can split on
space and treat these as a single field that I ignore anyway.
Also, the way we are importing stuff into Kraken right now is really hacky. I've been
struggling over the last months to try and figure out how to make a single machine that
has to look at ALL of the udp2log webrequest packets save unsampled data into HDFS. Its
tough. Another reason I haven't worried much about the byteoffset\thostname problem
is because I haven't been sure if we will be using the Kafka Hadoop Consumer class
(that inserts the byte offsets) in the long term.
On Jan 22, 2013, at 10:13 AM, Andrew Otto <otto(a)wikimedia.org> wrote:
> Cool, thanks. Yeah we know these are problems for sure. We're really focused on
trying to make the data you see reliable right now, which is one of the reasons why this
has not been a priority.
>
1) Kafka byte
offset is separated from hostname by a tab.
This is annoying, but since thus far I
haven't cared about doing any analysis on hostname or byte offset, I can split on
space and treat these as a single field that I ignore anyway.
>
>> 2) Other fields are separated by a space.
>
>> 3) The content-type field contains unescaped spaces.
> We know that there are spaces, but I had no idea they were coming from Varnish! I
thought Varnish was the best at escaping all of its fields. Grrrrr! Using tabs as the
field delimiter is high on our priority list. We didn't change it a few months ago
because the fundraiser was happening, and also changing this can break other downstream
scripts, especially Erik Zachte's workflow that generates everything you see on
stats.wikimedia.org. We want to get this taken care of in the next few weeks.
>
>
>
>
>
> On Jan 22, 2013, at 5:18 AM, Ori Livneh <ori(a)wikimedia.org> wrote:
>
>> Sort out the field separator issue in your handling of squid logs first.
>>
>> To summarize:
>> 1) Kafka byte offset is separated from hostname by a tab.
>> 2) Other fields are separated by a space.
>> 3) The content-type field contains unescaped spaces.
>> 4) Beeswax only supports splitting on a single character.
>>
>> As a result:
>> 1) Byte offset is not separable from the hostname
("316554683463cp1043.wikimedia.org")
>> 2) Spaces in content-type causes the field to span a variable number of columns,
making it impossible to select the user agent string.
>>
>> I'd like a solution to this that does not require that I provide a jar file
for customized string processing.
>>
>> --
>> Ori Livneh
>>
>>
>> On Tuesday, January 22, 2013 at 2:05 AM, David Schoonover wrote:
>>
>>> Yes! We've talked a bit about this paper when thinking about the
structure of our data storage and processing. To me the path Twitter followed seems very
reasonable, so it's encouraging to hear that it looks that way to someone who gets
dirty with data on a daily basis.
>>>
>>> As it stands now, we weren't planning on enforcing any schema
requirements in Kraken, but it'd be interesting to experiment with a standardized
event-data format if y'all were in favor of it. Our most recent pass at a schema[1] --
mostly for binary serialization, to save bits -- has an otherwise-untyped (String-String)
map for the KV pairs of the data payload. We intended to use an additional, optional field
to permit specifying a sub-schema to apply strong typing to incoming event data. (We plan
on storing things with Avro, but it's easy enough to convert between it and
JSONSchema.) Event subclasses would be more flexible but require custom processing for
each class. I'd normally oppose a standard model (Google doesn't use one
internally, for example) but as Twitter made it work, I think it's worth exploring.
>>>
>>> Thoughts?
>>>
>>> [1]
https://www.mediawiki.org/wiki/Analytics/Kraken/Data_Formats#Event_Data_Sch…
>>>
>>> --
>>> David Schoonover
>>> dsc(a)wikimedia.org (mailto:dsc@wikimedia.org)
>>>
>>>
>>> On Thursday, 17 January 2013 at 2:00 p, Dario Taraborelli wrote:
>>>
>>>>
http://arxiv.org/pdf/1208.4171.pdf
>>>>
>>>> This is a pretty interesting and accessible description of best practices
and design decisions driven by practical problems they had to solve at Twitter in the area
of client-side event logging, funnel analysis, user modeling.
>>>> E3: check out section "3.2 Client Events" in particular, which
is quite relevant to EventLogging.
>>>>
>>>> Dario
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>>>
>>>
>>>
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>>
>>
>>
>>
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