答复: BinaryObject pros/cons

[Shawn Du <sh...@neulion.com.cn>]

 

Hi,

 

In one of our project, we compact java objects which have lots of long zeros. It save disk greatly when serialization. 

Thus slow Disk IO operations become fast CPU operations and performance is improved.  

Data compact algorithm is inspired by this paper http://www.vldb.org/pvldb/vol8/p1816-teller.pdf.

 

Thanks

Shawn

发件人: Vladimir Ozerov [mailto:vozerov@gridgain.com] 
发送时间: 2016年10月28日 5:21
收件人: user@ignite.apache.org
主题: Re: BinaryObject pros/cons

 

Hi,

 

I am not very concerned with null fields overhead, because usually it won't be significant. However, there is a problem with zeros. User object might have lots of int/long zeros, this is not uncommon. And each zero will consume 4-8 additional bytes. We probably will implement special optimization which will write such fields in special compact format.

 

Vladimir.

 

On Thu, Oct 27, 2016 at 10:55 PM, vkulichenko <valentin.kulichenko@gmail.com <ma...@gmail.com> > wrote:

Hi,

Yes, null values consume memory. I believe this can be optimized, but I
haven't seen issues with this so far. Unless you have hundreds of fields
most of which are nulls (very rare case), the overhead is minimal.

-Val



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