What is the purpose of dbClearResult() in DBI/RMySQL/RMariaDB?

Question

SQL novice here. In the Hello World section of the RMySQL github page, there is the following -

# You can fetch all results:
res <- dbSendQuery(con, "SELECT * FROM mtcars WHERE cyl = 4")
dbFetch(res)
dbClearResult(res)

I don't understand the purpose of dbClearResult(). This is important to me because I'm working with a few large tables and dbClearResult(rs) can be very slow at times (taking minutes to complete). However, if I go into the mysql shell I can simply kill a query instantaneously.

So, what is the purpose of dbClearResult() and is there any way to avoid it or speed it up?

Answer 1

From the DBI documentation for dbClearResult:

Frees all resources (local and remote) associated with a result set. In some cases (e.g., very large result sets) this can be a critical step to avoid exhausting resources (memory, file descriptors, etc.)