Re: [HACKERS] Postgres Speed or lack thereof

I have added this to the TODO list:

* improve dynamic memory allocation by introducing tuple-context memory  allocation
* add pooled memory allocation where allocations are freed only as a group 



> We could use 4 methods for dynamic allocation:
> 
> 1)    malloc/free - for persistent storage allocation
> 
> 2)    palloc/pfree - for storage belonging to some context and
>     which we can keep track of and free explicitly
> 
> 3)    fast_palloc - for storage which impossible, too difficult or too
>     expensive to keep track of. This storage should be allocated with
>     fast and simple inline code from bigger chunks allocated with palloc.
>     This storage would never freed explicitly, so that code could be
>     simple and fast, but the big chunks would be freed automatically at
>     the end of the transaction.
> 
> 4)    fast_talloc - we could introduce a `tuple' context handled like
>     fast_palloc for storage used only while processing one tuple.
>     This storage could be fast allocated from few big chunks allocated
>     with palloc and freed explicitly after the tuple has been processed.
>     This could avoid the overhead of many malloc/palloc while reducing
>     the overall memory usage for transaction which process many rows.
>     The total cost per tuple could be one palloc and one pfree.
>     We could also simply reuse the chunks for every tuple and pfree them 
>     only at the end of the transaction. This would cost one palloc/pfree
>     per transaction.
> 
> This would require revising the code and changing palloc/pfree with the new
> functions where appropriate, but this could be done gradually because the
> old palloc/pfree are always safe.
> 
> -- 
> Massimo Dal Zotto
> 
> +----------------------------------------------------------------------+
> |  Massimo Dal Zotto               email: dz@cs.unitn.it               |
> |  Via Marconi, 141                phone: ++39-0461534251              |
> |  38057 Pergine Valsugana (TN)      www: http://www.cs.unitn.it/~dz/  |
> |  Italy                             pgp: finger dz@tango.cs.unitn.it  |
> +----------------------------------------------------------------------+
> 
> 


--  Bruce Momjian                        |  http://www.op.net/~candle maillist@candle.pha.pa.us            |  (610)
853-3000+  If your life is a hard drive,     |  830 Blythe Avenue +  Christ can be your backup.        |  Drexel Hill,
Pennsylvania19026