Re: [h2] Manage MVStore file growth: Drop old versions? Best parameters? Entry order?

2014-04-10 Thread Markus Kropf 
Thank you very much, Thomas, your hint on LSM-trees opened my eyes!
(a little smalltalk: sometimes I tend to forget that there are laws of 
nature in computer science too... naive thought: That doesn't fit into 
memory, so lets store it in a database, DBs are so smart these days, they 
will give me fast random access on the API side and huge storage quantities 
on the persistence side, and a magic cache will solve all difficulties...)

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[h2] Manage MVStore file growth: Drop old versions? Best parameters? Entry order?

2014-04-09 Thread Markus Kropf 
Hi, I'm trying MVStore to implement a change tracking feature in a large 
graph structure, using several MVMaps with custom data types. In a recent 
test, I had a load like this:

Opened new store, added ~1M entries, with roughly 10Byte serialized data 
each, closed. MVStore file size was ~1.6 GB
Store version was ~750, obviously the number of autocommits that happened.
Keys have a near to random distribution.
In my case, some latest versions are useful to realize n concurrent readers 
with 1 writer. Most old versions could be discarded. I mean, 1.6GB is 
little large when, ideally, just ~10MB would do. Can you give me some 
advice? Is there an option to discard old versions? Can I optimize chunk 
sizes, and what are the criteria? Play with autocommit frequency?

Using version 1.3.175

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