R语言操作mysql上亿数据量，ff包ffbase包和ETLUtils包

平时都是几百万的数据量，这段时间公司中了个大标，有上亿的数据量。

现在情况是数据已经在数据库里面了，需要用R分析，但是完全加载不进来内存。

面对现在这种情况，R提供了ff， ffbase ， ETLUtils 的解决方案。

它可以很简单的加载，转换数据库的数据进入R内存，ETLUtils 包现在已经扩展了read.odbc.ffdf

方法用来查询Oracle, MySQL, PostgreSQL & sqlite databases.。

下面我们就来展示一个例子。

require(ETLUtils)
 
login <- list()
login$user <- "bnosac"
login$password <- "YourPassword"
login$dbname <- "YourDB"
login$host <- "localhost/IPaddress"
 
require(RMySQL)
x <- read.dbi.ffdf(
query = "select * from semetis.keywords_performance_endofday", 
dbConnect.args = list(drv = dbDriver("MySQL"), 
dbname = login$dbname, user = login$user, password = login$password, host = login$host), 
VERBOSE=TRUE)
1> dim(x)
[1] 14969674       27
 
login <- list()
login$dsn <- "YourDSN"
login$uid <- "bnosac"
login$pwd <- "YourPassword"
require(RODBC)
x <- read.odbc.ffdf(
query = "select * from semetis.keywords_performance_endofday where date = CURRENT_DATE-1", 
odbcConnect.args = list(dsn = login$dsn, uid = login$uid, pwd = login$pwd),
x = x,
VERBOSE=TRUE)
1> dim(x)
[1] 15062904       27

指定本地ff文件路径

save.ffdf(ffdfname, dir=”/PATH/TO/STORE/FF/FILES”)

https://www.rdocumentation.org/packages/ffbase/versions/0.12.3/topics/save.ffdf

load.ffdf(dir=”/PATH/TO/STORE/FF/FILES”)

https://www.rdocumentation.org/packages/ffbase/versions/0.12.3/topics/load.ffdf

https://www.rdocumentation.org/packages/ETLUtils/versions/1.3/topics/read.dbi.ffdf