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Re: Avro file - Seek to specific offset and read
Hi Doug,

Adjusting the start and end offsets (returned by DataFileWriter.sync()) back by 16 bytes (DataFileConstants.SYNC_SIZE) fixed the issue.
This assumption is based on looking at the DataFileReader.pastSync() implementation.

97   public boolean pastSync(long position) throws IOException {
98     return ((blockStart >= position+SYNC_SIZE)||(blockStart >= sin.length()));
99   }

Let me know if this assumption is correct.

 From: Doug Cutting <[EMAIL PROTECTED]>
Sent: Friday, February 22, 2013 12:01 PM
Subject: Re: Avro file - Seek to specific offset and read

That should work.  It's hard for me to guess what's going wrong,
whether there's a bug in Avro, in your program, or perhaps just
unclear documentation.  Could you post a complete program that
demonstrates the issue?



On Wed, Feb 20, 2013 at 12:23 PM, Venkat <[EMAIL PROTECTED]> wrote:
> Hi All,
> Using DataFileReader, I'm trying to read data from a specific [start-offset]
> to an [end-offset]. Both the start and end offsets are marked with
> synchronization markers using DataFileWriter.sync()
> The following is the snipped I use to read the data back:
>         DataFileReader<GenericRecord> fileReader = new
> DataFileReader<GenericRecord>(input, reader);
>         fileReader.seek(startOffset);  // set to the start-offset
>         while(fileReader.hasNext() && !fileReader.pastSync(endOffset))
>         {
>             GenericRecord gr = fileReader.next();
>         }
> This, however, reads & returns more records than what I wrote between the
> two offsets.
> Appreciate your help regarding this.
> Thanks