Hi,
IMHO you need only when your columns are numeric X rows /100/100/8 MB. >>(12000000*3)/100/100/8 [1] 450
But one of your columns is group char. I'm suffering in the past in lot of things with massive data and R and recognize doing how many as possible in the database, or you have to upgrade your computer to 2-4GB like a database machine!?
regards, christian
Christoph Lehmann schrieb:
Hi
I just started with RMySQL. I have a database with roughly 12 millions rows/records and 8 columns/fields.
From all 12 millions of records I want to import 3 fields only.
The fields are specified as:id int(11), group char(15), measurement float(4,2).
Why does this take > 1G RAM? I run R on suse linux, with 1G RAM and with the code below it even fills the whole 1G of swap. I just don't understand how 12e6 * 3 can fill such a huge range of RAM? Thanks for clarification and potential solutions.
## my code library(RMySQL) drv <- dbDriver("MySQL") ch <- dbConnect(drv,dbname="testdb", user="root",password="mysql") testdb <- dbGetQuery(ch, "select id, group, measurement from mydata") dbDisconnect(ch) dbUnloadDriver(drv)
## end of my code
Cheers Christoph
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