mysqlrforeachdoparallelrmysql

RMySql doParallel failing

I am using parallel querying with RMySQL. Is it possible to share the connection between workers?

library(foreach)
library(doParallel)
library(RMySQL)

con <- dbConnect(MySQL(),
                 user = 'user',
                 password = 'password',
                 host = 'someip',
                 dbname = 'test01')  

numCores <- detectCores()
registerDoParallel(numCores)

foreach (i=1:3,.packages='RMySQL') %dopar% {
  dbGetQuery(con,paste0("INSERT INTO t VALUES ('Some Text')"))
}

dbDisconnect(con)

I got this error:

Error in { : task 1 failed - "Corrupt MySQL handle"
Solution

  • Is it possible to share the connection between workers?

    No, the connection maintains state of the progress of the query and its results. A separate connection per worker is required.