pig-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Apache Wiki <wikidi...@apache.org>
Subject [Pig Wiki] Update of "LoadStoreMigrationGuide" by PradeepKamath
Date Thu, 11 Feb 2010 22:19:56 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Pig Wiki" for change notification.

The "LoadStoreMigrationGuide" page has been changed by PradeepKamath.
http://wiki.apache.org/pig/LoadStoreMigrationGuide?action=diff&rev1=15&rev2=16

--------------------------------------------------

  == Table mapping old API calls to new API calls in rough order of call sequence ==
  || '''Old Method in !StoreFunc''' || '''Equivalent New Method''' || '''New Class/Interface
in which method is present''' || '''Explanation''' ||
  || No equivalent method || setStoreFuncUDFContextSignature() || !StoreFunc || This method
will be called by Pig both in the front end and back end to pass a unique signature to the
Storer. The signature can be used to store into the UDFContext} any information which the
Storer needs to store between various method invocations in the front end and back end.||
- || No equivalent method || relToAbsPathForStoreLocation() || !StoreFunc || Pig runtime will
call this method to allow the Storer to convert a relative load location to an absolute location.
An implementation is provided in !LoadFunc (as a static method) which handles this for hdfs
files and directories. 
+ || No equivalent method || relToAbsPathForStoreLocation() || !StoreFunc || Pig runtime will
call this method to allow the Storer to convert a relative load location to an absolute location.
An implementation is provided in !LoadFunc (as a static method) which handles this for hdfs
files and directories.||
  || No equivalent method || checkSchema() || !StoreFunc || A Store function should implement
this function to check that a given schema is acceptable to it ||
  || No equivalent method || setStoreLocation() || !StoreFunc || This method is called by
Pig to communicate the store location to the storer. The storer should use this method to
communicate the same information to the underlying !OutputFormat. This method is called multiple
times by pig - implementations should bear in mind that this method is called multiple times
and should ensure there are no inconsistent side effects due to the multiple calls.||
  || getStorePreparationClass() || getOutputFormat() || In the old API, getStorePreparationClass()
was the means by which the implementation could communicate to Pig the !OutputFormat to use
for writing - this is now achieved through getOutputFormat(). getOutputFormat() is NOT an
optional method and implementation SHOULD provide an !OutputFormat to use. The methods in
the !OutputFormat (and underlying !RecordWriter and !OutputCommitter) will be called by pig
in the same manner (and in the same context) as by Hadoop in a map-reduce java program.||

Mime
View raw message