It appears that fetch() gets only the first 500 rows by default. I
don't see this in the documentation, but
timeinfo <- fetch(rs)
gets only 500 rows where
timeinfo <- fetch(rs,n=-1)
gets (correctly) 736 for the same query. Is this an undocumented
feature? I played with this data for an alarming amount of time
before I realized that I was missing a third of the data. I appear to
be using version 0.4-5. I'll upgrade to 0.4-6 Real Soon Now. My
first attempt failed for some reason.
--
Jay Pfaffman pfaffman at relaxpc.com
+1-415-821-7507 (H) +1-415-810-2238 (M)
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On Thu, 8 Aug 2002, Jay Pfaffman wrote: %It appears that fetch() gets only the first 500 rows by default. I %don't see this in the documentation, but it is not in ?fetch but> describe(manager)MySQLManager id = (5649) Driver name: MySQL Max connections: 10 Conn. processed: 1 Default records per fetch: 500 Open connections: 1 where manager is your the output of dbManager("MySQL") reveals some info % timeinfo <- fetch(rs) % %gets only 500 rows where % % timeinfo <- fetch(rs,n=-1) % %gets (correctly) 736 for the same query. Is this an undocumented %feature? I played with this data for an alarming amount of time %before I realized that I was missing a third of the data. I appear to %be using version 0.4-5. I'll upgrade to 0.4-6 Real Soon Now. My %first attempt failed for some reason. undocumented? err, you can always look up the sources and in RMySQL.R (version 04-6) this feature is documented line 647 "MySQLManager" <- function(max.con=10, fetch.default.rec = 500, force.reload=F) line 1400 "fetch.MySQLResultSet" <- function(res, n=0) ## Fetch at most n records from the opened resultSet (n = -1 means ## all records, n=0 means extract as many as "default_fetch_rec", ## as defined by MySQLManager (see describe(mgr, T)). regards, JN % %-- %Jay Pfaffman pfaffman at relaxpc.com %+1-415-821-7507 (H) +1-415-810-2238 (M) % %-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- %r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html %Send "info", "help", or "[un]subscribe" %(in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch %_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._ % *********************************************************************** Jens Nieschulze Institute for Forest Biometrics & Phone: ++49-551-39-12107 Applied Computer Science Fax : ++49-551-39-3465 Buesgenweg 4 37077 Goettingen E-mail: jniesch at uni-forst.gwdg.de GERMANY http://www.uni-forst.gwdg.de/~jniesch -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
Hi, Jay Pfaffman wrote:> It appears that fetch() gets only the first 500 rows by default. I > don't see this in the documentation, but > > timeinfo <- fetch(rs) > > gets only 500 rows where > > timeinfo <- fetch(rs,n=-1) > > gets (correctly) 736 for the same query. Is this an undocumented > feature? I played with this data for an alarming amount of time > before I realized that I was missing a third of the data. I appear to > be using version 0.4-5. I'll upgrade to 0.4-6 Real Soon Now. My > first attempt failed for some reason.Hmm, help(fetch) says ... Usage: fetch(res, n, ...) Arguments: res: a `resultSet' object. This object needs to be the result of a `SELECT' or `SELECT'-like statement, as produced by `dbExec.' or `dbExecStatement.' SQL statements such as `INSERT', `DELETE', do not create result sets. n: maximum number of records to retrieve per fetch. Use `n = -1' to retrieve all pending records. Some implementations may recognize other special values (RS-MySQL interprets `n = 0' to mean "use whatever default was set in the call to `MySQL'). ... : any other database-engine specific arguments. and if you follow the link to help(MySQL) ... Usage: MySQL(max.con = 10, fetch.default.rec = 500, force.reload = F) Arguments: max.con : maximum number of connections that we intended to have open. This can be up to 100, a limit defined at compilation time. Strictly speaking this limit applies to MySQL servers, but clients can have (at least in theory) more than this. fetch.default.rec: number of records to fetch at one time from the database. (The `fetch' method uses this number as a default.) force.reload: should we reload (reinitialize) the client code? Setting this to `TRUE' allows you to change default settings. Notice that all connections should be closed before re-loading. so I think it's clear (but I'm open to suggestions). Regards,> > -- > Jay Pfaffman pfaffman at relaxpc.com > +1-415-821-7507 (H) +1-415-810-2238 (M) > > -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- > r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html > Send "info", "help", or "[un]subscribe" > (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch > _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._-- David A. James Statistics Research, Room 2C-253 Phone: (908) 582-3082 Bell Labs, Lucent Technologies Fax: (908) 582-3340 Murray Hill, NJ 09794-0636 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._