lua_share_dict:set(key,value,expiretime) ngx_slab_alloc() failed: no memory in lua_shared_dict zone

songjun435 · 2014-09-28T23:10:52+00:00

> Only for Lua modules doing IO :) Right, in fact SciLua would have nothing to do with that. Thats true. > As long as every non-dividable bunch of y...

lua_share_dict:set(key,value,expiretime) ngx_slab_alloc() failed: no memory in lua_shared_dict zone

songjun435

I have a question about the method lua_share_dict:set(key,value,expiretime).

first,I alloc 16kB space

lua_share_dict test 16k

then I call the method test:set(key,value,60) every 1 second

and the 16k space just store 60 key/value

so ,when I set 61th k/v(the space is exceeded by then former inserted 60 k/v), it will print log:ngx_slab_alloc() failed: no memory in lua_shared_dict zone

but, if I set the expired time to 58

There is no log like ngx_slab_alloc() failed: no memory in lua_shared_dict zone

I think this is because when I set 61th k/v,some former k/v has expired,which freed the memory.

so my question is the method lua_share_dict:set(key,value,expiretime)

free the memory when it is expired automaticly?

agentzh

Hello!

On Sun, Sep 28, 2014 at 8:10 AM, songj songj wrote:
> so my question is the method lua_share_dict:set(key,value,expiretime)
> free the memory when it is expired automaticly?
>

The lua_shared_dict thing frees memory in a way that is kinda similar
to an incremental GC. That is, every get() and set() will try to free
up a few least recently used *and* expired items.

BTW, ensure your nginx core (or OpenResty) is recent enough because
there was a memory fragmentation bug for slabs larger than the page
size in older nginx cores.

Regards,
-agentzh