eviction in Monetdb

Stefan Manegold Stefan.Manegold at cwi.nl
Thu Sep 15 09:09:05 CEST 2016


Hi Narendra,

despite its possibly misleading name, MonetD's BBP has nothing to do
with a classical database buffer pool. No such thing exists in MonetDB.
BBP is more a catalog of all (both persistent and transient) BATs rather
than a buffer pool.

And to also answer one of your recent questions, there is no way to determine
whether a BAT is physically in memory or not in MonetDB. Using memory mapped files,
MonetDB leaves it to the operting systems virtual memory management to control
when which (parts of --- on a memory page-wise granularity --- which) BAT(s) are
in physical memory.

Best,
Stefan

----- On Sep 15, 2016, at 8:52 AM, Narendra Pradeep narenpradeeptigers at gmail.com wrote:

> Hello ,
> Need to know about monetdb eviction policy ? My understanding is Monetdb creates
> a buffer pool {BBP} and inserts all the bats that are used . But not sure when
> does Monetdb deletes the bat from the buffer pool and what eviction policy does
> it use (like LRU or based on some threshold) ?
> 
> Thanks
> 
> 
> _______________________________________________
> developers-list mailing list
> developers-list at monetdb.org
> https://www.monetdb.org/mailman/listinfo/developers-list

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