[R-sig-DB] Time taken by dbExistsTable()

[Mark Van De Vyver]

Hi,
Fristly thanks for the efforts put into the DBI package for R-project.
 This has enhanced my use of R considerably - several colleagues raise
their eye brows when I indicate I no-longer use SAS.....

My set-up:
Windows-xp
R-2.2.1
R-MySQL package.
MySQL 5.0.19-nt (using TCP-IP connections)

I will highlight that the db in question has 10,000+ tables, so the
following may not be of general interest/concern.

I have noticed that considerable time is used by the function
dbExistsTable(), about 5 times more than the SQL 'show table' work
around -  in my case this translates to about a 6 hour saving.
This of course may be due to my 'set-up' rather than dbExistsTable()?

Is it possible my set-up is at fault?
Is it possible to improve this time further using R-DBI?

The timing results are shown below.

Regards
Mark

system.time(
	for(tbli in tblunionlist[1:15]){
		tblExist <- dbExistsTable(dbcon, tbli)
	}
)

system.time(
	for(tbli in tblunionlist[1:15]){
		myshowstring<-paste("SHOW TABLE STATUS FROM `myDB` LIKE '",tbli, "'", sep="")
		mytblstatus<-mysqlQuickSQL( dbcon, myshowstring )
		if( identical( identical(mytblstatus,data.frame(NULL)),F) ) {
			tblExist <- TRUE
		}
	}
)


[1]  4.96  1.52 29.20    NA    NA
[1] 1.99 0.30 5.64   NA   NA