Which getAll() call do you mean? On Sun, Jan 1, 2012 at 5:34 PM, Dmitriy Ryaboy <[email protected]> wrote:
> That getAll() call destroyed our lazy deserialization optimizations, btw... > it's unfortunate that even if my loader constructs optimized tuples, they > immediately get turned into object-bloated regular tuples :(. > > D > > On Sun, Jan 1, 2012 at 12:36 AM, Daniel Dai <[email protected]> wrote: > > > Hi, Stan, > > I miss one point in my previous mail. We do apply PushUpFilter rule > first, > > so filter will be pushed in front of the added ForEach in most cases. > There > > is also a bug before (See PIG-2339) but current code should be fixed. So > > even you use as clause to change the name, partition filter should still > > apply. > > > > Daniel > > > > On Sat, Dec 31, 2011 at 7:37 PM, Stan Rosenberg < > > [email protected]> wrote: > > > > > Just to be clear, the concrete syntax had a typo; should have been: > > > > > > A = load 'daily_activity' USING HiveLoader WHERE date_partition >= > > > 20110101 and date_partition <= 20110201; > > > > > > On Sat, Dec 31, 2011 at 10:34 PM, Stan Rosenberg > > > <[email protected]> wrote: > > > > > > > > A = load 'daily_activity' from HiveLoader where date_partition >= > > > > 20110101 and date_partition <= 20110201; > > > > > > > > stan > > > > > > > > On Sat, Dec 31, 2011 at 9:42 PM, Daniel Dai <[email protected]> > > > wrote: > > > >> Hi, Stan, > > > >> Foreach is inserted only if you have "as" in "load" statement. This > is > > > to > > > >> assure the data loaded conforms with "as" clause. At some point > there > > > is a > > > >> bug in implementation, this should be fixed in PIG-2346 and will be > > > >> included in all subsequent releases. > > > >> > > > >> Thanks, > > > >> Daniel > > > >> > > > >> On Fri, Dec 30, 2011 at 9:54 AM, Stan Rosenberg < > > > >> [email protected]> wrote: > > > >> > > > >>> Howdy All, > > > >>> > > > >>> I am resurrecting my previous message sent to the list on Dec. 7. > > Let > > > >>> me first summarize. In a nutshell, as far as I can tell, > > > >>> partition-aware loading is broken > > > >>> in pig, and the culprit is PIG-1188 wherein the final decision was > to > > > >>> introduce project & cast, i.e, foreach, after load. There are two > > > >>> problems with that approach. > > > >>> First, as indicated in my original message, 'getPartitionKeys' is > > > >>> never invoked because instead of the expected instruction sequence > > > >>> 'load; filter', PIG-1188 > > > >>> changed it to 'load; foreach; filter'. Second, if a loader already > > > >>> happens to project & cast in order to adhere the data to the > schema, > > > >>> then the foreach synthesized > > > >>> by pig is a waste of time. > > > >>> > > > >>> Essentially, we had to undo the patch in 'PIG-1188' in order to get > > > >>> partition filters to work; this enabled us to implement a > HiveLoader > > > >>> very much like > > > >>> HCatLoader which incidentally is also broken for the very same > > reason. > > > >>> This is obviously a hack and a real solution is needed. > > > >>> If the decision made in PIG-1188 cannot be re-considered, then I > > > >>> suggest that we revisit the logic which is used to pass partition > > > >>> filters to partition-aware loaders. > > > >>> > > > >>> Many thanks! > > > >>> > > > >>> stan > > > >>> > > > >>> > > > >>> > > > >>> ---------- Forwarded message ---------- > > > >>> From: Stan Rosenberg <[email protected]> > > > >>> Date: Wed, Dec 7, 2011 at 12:24 PM > > > >>> Subject: Partition keys in LoadMetadata is broken in 0.10? > > > >>> To: [email protected] > > > >>> > > > >>> > > > >>> Hi, > > > >>> > > > >>> I am trying to implement a loader which is partition-aware. As > > > >>> prescribed, my loader implements LoadMetadata, however, > > > >>> getPartitionKeys is never invoked. > > > >>> The script is of this form: > > > >>> > > > >>> X = LOAD 'input' USING MyLoader(); > > > >>> X = FILTER X BY partition_col == 'some_string'; > > > >>> > > > >>> and the schema returned by MyLoader.getSchema includes the column > > > >>> 'partition_col' which is of type 'chararray'. > > > >>> > > > >>> > > > >>> After debugging pig, I have found what appears to be a bug in the > new > > > >>> code (version 0.10 snapshot and also in 0.9.1). The reason > > > >>> MyLoader.getPartitionKeys is never invoked is due to the wrongfully > > > >>> inserted > > > >>> 'foreach' after the 'load' and before the 'filter'. The code in > > > >>> TypeCastInserterTransformer.check used to return 'false' if the > > > >>> schemas matched or all fields were of type 'bytearray'; cf. pig > > > >>> version 0.8.1. > > > >>> Effectively, the above script gets transformed into: > > > >>> > > > >>> X = LOAD 'input' USING MyLoader(); > > > >>> X = FOREACH X GENERATE ...; > > > >>> X = FILTER X BY partition_col == 'some_string'; > > > >>> > > > >>> Subsequently, PartitionFilterPushDownTransformer.check observes > that > > > >>> the immediate successor of 'load' is _not_ 'filter', whence > > > >>> getPartitionKeys is never invoked. > > > >>> > > > >>> Any suggestions? > > > >>> > > > >>> Thanks, > > > >>> > > > >>> stan > > > >>> > > > >>> P.S. While in the above case the 'foreach' can be avoided, in > general > > > >>> typecasting may need to be performed if the user-provided schema > does > > > >>> not match the one returned by the loader. > > > >>> I think the general case needs to be handled correctly, perhaps by > > > >>> ignoring all synthetic operators after the 'load'. (This is just a > > > >>> wild guess.) > > > >>> > > > > > >
