Re: Which node is doing the work?

Hey Jake,

On Sep 28, 2007, at 10:31 , Jake Conk wrote:

> When I'm querying data from a api node that is connected to a ndbd
> storage node where is the work of the query done, on the api node or
> the ndbd storage node?

Both. Depending on what you do, but generally: looking up data using eg indexes is done on the data nodes, but sorting or doing anything with the retrieved data is done on the SQL or API nodes. There is a condition pushdown feature, which could push down more work to the data nodes.

Btw, an API/SQL node is getting a transaction 'coordinator' in a round-robin way, meaning it will 'ask' one data node (the next one so to speak), but will get data from all (if there was data of course).

Cheers,

Geert

-- 
Geert Vanderkelen, Senior Support Engineer
MySQL GmbH, Germany, www.mysql.com





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