Re: root file splitting and merging

Thanks Philippe.
Approximate size is fine.
But my use case is :
I have a large root file (say 2G), and want a efficient way to split it into small bulks(say 64M), and store these bulks on different computing node to analyse it separately.
I wonder if I can read the root file sequentially, object-by-object, to a buffer, and save it to a new file when the the buffer >= 64M. I have few knowledge about root, so I would appreciate if you can give me some example codes.
Cheers,
Donal
On 2011/11/7 23:40, Philippe Canal wrote:
> Hi Donal.
>
> There is currently no easy way to enforce that a ROOT file is exactly
> in 64M chunks. However you can get close (within statistical
> fluctuations) by setting the 'auto-flush' size is 64M when writing the
> TTree (SetAutoFlush(-64*1024*1024) )
>
> Cheers,
> Philippe.
>
> On 11/5/11 3:56 AM, donal0412 wrote:
>> Hi ROOT experts and users,
>> I'm considering to use HDFS to store ROOT files and use map-reduce
>> framework to process the files (reconstruction,analysis,MC).
>> I wonder if it's possible to have an efficient way to split the ROOT
>> file into fixed size(say 64M) , and merge some ROOT files into one file.
>>
>> Thanks !
>> Donal
>>
Received on Tue Nov 08 2011 - 07:44:02 CET