Java Exception error while reading large data in R from DB using RJDBC.
I didn't have the same exception yet, but please make sure you have a stable connection (avoid wlan).
I personally ran out of memory very often and had to make several queries, combining the results in R instead.
This is probably not the best thing to do, but worked for me to fetch large amounts of data, though it takes a while:
res<-dbSendQuery(conn,query)
result<-list()
i=1
result[[i]]<-fetch(res,n=100000)
while(nrow(chunk <- fetch(res, n = 100000))>0){
i<-i+1
result[[i]]<-chunk
}
allResults<-do.call(rbind,result)
On 30.10.2012, at 12:32, aajit75 wrote:
Dear List,
Java Exception error while reading large data in R from DB using RJDBC.
I am trying to read large data from DB table(Vectorwise), using RJDBC
connection.
I have tested the connection with small size data and was able to fetch DB
tables using same connection(conn as in my code).
Please suggest where am i going wrong or alternate option to solve such
issues while reading large DB table.
drv <- JDBC(paste(db_driver, sep = ""),
paste(db_jar_file, sep = ""),
identifier.quote="`")
conn <<- dbConnect(drv, paste(db_server, sep = ""),
paste(db_server_lgn, sep = ""),
paste(db_server_pwd, sep = ""))
s <- sprintf("select * from cypress_modeldev_account_info")
temp <- dbGetQuery(conn, s)
Error in .jcheck() :
Java Exception <no description because toString() failed>.jcall(rp, "I",
"fetch", stride)<S4 object of class "jobjRef">
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