[BioC] max query length in RdbiPgSQL

William McCoy wdmccoy at geo.umass.edu
Tue Sep 13 20:45:10 CEST 2005

I have been using RdbiPgSQL successfully for a year or two.  I commonly 
save my queries in text files that I can use either in PostgreSQL's psql 
(useful for testing and editing) or in R using readLines().  For example 
(in R):

conn <- dbConnect(PgSQL(), host = "localhost", dbname = "agdb")
test.sql < readLines("queryfile")
test.df <- dbGetQuery(conn, paste(test.sql, collapse = " "))

This works fine for all the multiline files I have tried -- except one.
I have recently encountered a problem with a moderately complex, long 
query (459 characters).  I can execute the query with no problem in psql 
and it returns the 14 rows that I expect.  When I execute the query in R 
as above, I get a dataframe with the expected column names, but no rows. 
  I get no error message.  I am wondering if the query string is too 
long.  Is there a maximum length for queries in RdbiPgSQL.

I am not a regular subscriber to bioconductor, so please reply to me 
personally if you can help.  Thanks.


Dr. William D. McCoy
Assoc. Prof.
University of Massachusetts, Amherst
wdmccoy at geo.umass.edu

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