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

[Jeffrey Horner]

christophe dutang wrote on 10/31/2008 03:28 PM:
> 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?

Try upgrading R to 2.8.0.

Can you provide your code to the list... or pseudo code so that we can 
troubleshoot? Specifically are you calling fetch() or dbApply()?

Jeff

> 
> 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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> 
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