Records/block and clustersize for LOB area

RealHeavyDude

RealHeavyDude

Well-Known Member
Sun Solaris 64Bits/OpenEdge 10.1C SP 3

I did not find any recommendation for the records per block and cluster size settings for a storage area that is dedecated for storing LOBs.

The LOBs which will be stored in the database will be XML messages up to a size of 10MB. After the application has processed the XML documents they must be stored and made visible to the users for quality control.

To me a record per block setting of 1 and a cluster size of 8 do make sense. I was thinking about a cluster size of 512 but I don't see any advantage.

Does anybody have experince with storing LOBs about this size in the database?

Any input is welcomed.

Thanks in advance,
RealHeavyDude.
 
RPB should be 1.

Why don't you see an advantage to a cluster size of 512? A 10MB XML doc is going to consume 128 blocks (assuming an 8k db block size). 4 of those will take up a whole cluster. How frequently do you add an XML doc during peak periods? If the frequency is in seconds I would think that 512 is very beneficial even during OLTP processing. Regardless I would think that this area is going to be fairly large and that you would thus want a large cluster size in order to optimize OLAP and maintenance activities as well.
 
Okay - after having read you reply I have to admit that I fully agree with you Tom.

One could always learn - I should have mentioned that we're talking about 1 XML document per day. Keeping the XML documents for 30 days would require a +/- 300MB large area - Assuming that the space of the LOBs deleted will be available again.


Thanks, RealHeavyDude.
 
If processing those big xml demands good performance, you might also want to look at vtd-xml, the next generation XML processing model that is far more powerful than DOM and SAX

<a href="http://vtd-xml.sf.net">http://vtd-xml.sf.net</a>
 
Is this something you are selling? Two posts and they are both hyping this product!

Note that whatever the virtues, it isn't the same as something built in to ABL ... and the SAX handlers in ABL are awfully good as far as I can tell.
 
You must log in or register to reply here.
Back
Top