One issue with the bucketing is that the number of sources on any given day is dynamic. On some days it's 4, others it's 14 and it's also constantly changing. I am hoping to use some of the features of the ORC files to almost make virtual partitions, but apparently I am going to run into issues either way.
On another note, is there a limit to hive and partitions? I am hovering around 10k partitions on one table right now. It's still working, but some metadata operations can take a long time. The Sub-Partitions are going to hurt me here going forward I am guessing, so it may be worth flattening out to only days, even at the expense of read queries... thoughts? On Sat, Aug 10, 2013 at 11:46 AM, Nitin Pawar <[email protected]>wrote: > Agree with Edward, > > whole purpose of bucketing for me is to prune the data in where clause. > Else it totally defeats the purpose of splitting data into finite number of > identifiable distributions to improve the performance. > > But is my understanding correct that it does help in reducing the number > of sub partitions we create at the bottom of table can be limited if we > identify the pattern does not exceed a finite number of values on that > partitions? (even if it cross this limit bucketting does take care of it > upto some volume) > > > On Sat, Aug 10, 2013 at 10:09 PM, Edward Capriolo > <[email protected]>wrote: > >> So there is one thing to be really carefully about bucketing. Say you >> bucket a table into 10 buckets, select with where does not actually prune >> the input buckets so many queries scan all the buckets. >> >> >> On Sat, Aug 10, 2013 at 12:34 PM, Nitin Pawar <[email protected]>wrote: >> >>> will bucketing help? if you know finite # partiotions ? >>> >>> >>> On Sat, Aug 10, 2013 at 9:26 PM, John Omernik <[email protected]> wrote: >>> >>>> I have a table that currently uses RC files and has two levels of >>>> partitions. day and source. The table is first partitioned by day, then >>>> within each day there are 6-15 source partitions. This makes for a lot of >>>> crazy partitions and was wondering if there'd be a way to optimize this >>>> with ORC files and some sorting. >>>> >>>> Specifically, would there be a way in a new table to make source a >>>> field (removing the partition)and somehow, as I am inserting into this new >>>> setup sort by source in such a way that will help separate the >>>> files/indexes in a way that gives me almost the same performance as ORC >>>> with the two level partitions? Just trying to optimize here and curious >>>> what people think. >>>> >>>> John >>>> >>> >>> >>> >>> -- >>> Nitin Pawar >>> >> >> > > > -- > Nitin Pawar >
