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Ask PG: What's up with the 2GB limit?

4 points by zacharydanger ↗ HN
32-bit systems can handle up to 4GB and any modern Linux system with a CPU that supports Physical Address Extension can use up to 64GB.

How are you coming up with your 2GB limitation?

10 comments

[ 4.9 ms ] story [ 33.9 ms ] thread
pg
There's 4GB of physical memory on the server, but for various reasons we only end up with about 2GB of usable heap space.

Rtm just placed an order for a new server, so we should have more memory and a somewhat faster CPU soon.

thepanister
Well, Don't you think that if you make pagination for comments of a story, that could help?

For example, if a story has 50 comments, then it should be devided into 2 pages, each page shows 25 comments... and as a result it will use less memory?

pg
That would not use less memory. It's not the html pages that are stored in memory, but the individual comments.
thepanister
Yes I know that the individual comments are the ones stored in the memory. But it takes a while to load anyway. like the feature request story... it takes around 11 seconds to load.

Thanks for making it clear to me, I really appreciate it. :)

mixmax
This would presumably give some problems with votes. For instance, a comment in a long thread that starts on page 2 would have a very small chance of making it to page 1 since only a subset of users would look at the second page thus having a chance to vote it up.
Jem
This was discussed in pg's original submission on why things had been slow lately. Do we need this separate submission?
[dead] losethos
Signed 32bit numbers are +/- 2 Gig. Many x86 instructions only work with signed 32-bit displacement.