Nicolas Pitre  wrote:

quoted text
> You'll have memory usage issues whenever such objects are accessed,

> loose or not.  However, once those big objects are packed once, they can

> be repacked (or streamed over the net) without really "accessing" them.

> Packed object data is simply copied into a new pack in that case which

> is less of an issue on memory usage, irrespective of the original pack

> size.

And fortunately here we actually do stream the objects we have

chosen to reuse from the pack.  We don't allocate the entire thing

in memory.  Its probably the only place in all of Git where we can

handle a 16 GB (after compression) object on a machine with only

2 GB of memory and no swap.
Where little memory systems get into trouble with already packed

repositories is enumerating the objects to include in the pack.

This can still blow out their physical memory if the number of

objects to pack is high enough.  We need something like 160 bytes

of memory (my own memory is fuzzy on that estimate) per object.

Have 500k objects and its suddenly something quite real in terms

of memory usage.
--

Shawn.

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