Brian
if you would like to submit a patch for inclusion please see
http://wiki.apache.org/thrift/HowToContribute
- Jake
On Dec 16, 2011, at 6:47 PM, Brian Bloniarz wrote:
> Hi, I have a small patch for Java to optimize the heapspace footprint
> of (for example):
>
> struct OptIntPair {
> 1: i32 a
> 2: i32 b
> }
>
> Each instance will have an __isset_bit_vector which points to a BitSet,
> which points to a long[], adding around 50 bytes of overhead to this object.
>
> The patch changes this by storing a raw byte and doing direct bitfield
> operations, like:
> byte __isset_bitfield;
>
> public void unsetB() {
> __isset_bitfield = EncodingUtils.clearBit(__isset_bitfield, __B_ISSET_ID);
> }
> A little nasty, but a big space win: on my machine, this brings down the total
> size of an OptIntPair from 85 bytes to 25 bytes. A BitSet gets used as a
> fallback
> when more than 64 __isset entries are needed.
>
> Is this something that could be considered? The patch is attached. Other
> people have
> mentioned this shortcoming before, see slide 22 of:
> http://www.slideshare.net/aszegedi/everything-i-ever-learned-about-jvm-performance-tuning-twitter
>
> Thanks for such useful software,
> Brian Bloniarz
> <patch.isset_bitfield>
