[R-sig-DB] rmysql warning and its associated mysql error

[christophe dutang]

Hi,

I'm currently experiencing problem with the combination of mysql / Rmysql /
R when reading the result of a 'big' query. If I select only 4 variables of
my mysql table, the result dimension has 56972 rows, I read by pack of
50000, namely the first of 50000 and the second of 6972. In this cas I do
not get any DBI warning telling an error of mysql server. But If I read the
21 variables of my table, the result dimension is then 56972 x 21. In R, the
first read of 50000 rows is fine but second stops after reading 2182 rows...
and a DBI warning is raised

RS-DBI driver warning: (error while fetching rows)

This problem was raised in 2003, cf.
https://stat.ethz.ch/pipermail/r-help/2003-April/032708.html

But I found here http://www.mysqlperformanceblog.com/2007/07/06/, that "If
you do not check for error it can look as you've done with result set while
you only processed a portion of it, which can cause rather hard to catch
errors."

Does anyone experience this problem? and know how to solve it?

Thanks in advance

Christophe Dutang


PS : I use R 2.7.2 on windows XP pro with RMySQL_0.6-1 and a MySQL community
server 5.0

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