Grokbase Groups Pig user August 2010
FAQ
Actually, the intermediate won't been stored in memory. they will be
stored in a tmp directory o hdfs, and pig will help you clean up the
intermediate data when the job is finished.

Yes, BinStorage is a binary format for storing intermediate data and
know how to deserialize it to tuples

On Fri, Aug 20, 2010 at 3:35 PM, Defenestrator
wrote:
Right, in cases where you have to load multiple large relations and then do
some processing on each relations (filtering, aggregation) before joining
them together.  One wouldn't want to have all of the relations and
intermediate state in memory before the join.

So is BinStorage just storing the Tuples in an internal binary format that
is easily converted back to a Tuple when loaded (i.e. no csv parsing
necessary)?

Thanks.
On Fri, Aug 20, 2010 at 12:06 AM, Jeff Zhang wrote:

What do you mean "multiple relations with many tuples" ? Do you mean
join multiple data set ?
And Pig user BinStorage for storing intermediate data.


On Fri, Aug 20, 2010 at 2:42 PM, Defenestrator
wrote:
Thanks, Jeff.

A quick follow-up question relating to the loading/storing of data - what is
the best practice when dealing with multiple relations with many tuples, do
people typically STORE intermediate relations to minimize memory usage and
RELOAD the intermediate data for use later on in the same script? Because I
noticed that when tuples are written out using the TupleFormat, which
outputs text with an additional parenthesis that would cause a subsequent
PigStorage LOAD to get extra parenthesis characters, right?
On Thu, Aug 19, 2010 at 1:50 AM, Jeff Zhang wrote:

I am afraid you should write your own LoadFunc to interpret the text.
From Pig 0.7, the local mode use the hadoop's standalone local mode,
so it will won't store all the data in memory, the data will been read
in stream mode, but this mode need more memory because each task is
executed in another jvm.


On Thu, Aug 19, 2010 at 12:48 AM, Defenestrator
wrote:
What loader should I use on csv files with quoted strings that contain
embedded commas?  (i.e. Embedded commas should not be a separator.)

And when LOADing large files in local mode, does Pig just store it all
in memory?  Or does it have memory management ala buffer managers in
DBMS's?


--
Best Regards

Jeff Zhang


--
Best Regards

Jeff Zhang


--
Best Regards

Jeff Zhang

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