On Fri, Aug 19, 2011 at 09:14:41PM -0700, Seth Falcon wrote:
> It's pretty hard to provide much guidance without more detail on the
> code you are actually running. Is there any chance you can provide a
> reproducible example or show some version of the code you are running?
Well, while reproducing the segfault problem that I just (separately)
emailed about, I discovered that I can also use that simpler case to
trigger a "close resultSet before continuing" error.
For this, do the bad update statement (see other email) once. This
first time, rather than segfaulting it will problably throw this
error:
> dbGetPreparedQuery(handle ,update.sql ,bind.data=bind.df)
Error in sqliteExecStatement(con, statement, bind.data) :
STRING_ELT() can only be applied to a 'character vector', not a 'NULL'
At that point, rather than running the bad update statement several more
times to get the segfault, instead do a query, which fails like so:
> dbGetQuery(handle ,"select count(*) from atp_1")
Error in sqliteExecStatement(con, statement, bind.data) :
RS-DBI driver: (connection with pending rows, close resultSet before
continuing)
Note that my previous encounter with this error was while was while
doing insert statements not updates, and I never saw that
"STRING_ELT() can only be applied" error then. However, some of those
inserts probably failed due to integrity constraints on my SQLite
table, so to hand-wave a bit, perhaps that left the RSQLite connection
in a similar "pending rows" state.
Btw, so far, explicitly calling dbClearResult() right before
dbBeginTransaction() seems to prevent dbBeginTransaction() from ever
failing with that "close resultSet before continuing" error.
> Can you provide an outline of what you mean by "running background
> jobs"? Do you have more than one process inserting into the same
> SQLite database?
Yes, I used Sun Grid Engine to start up 5 or 6 R processes at once,
with each R process writing to the same SQLite database over NFS.
(Which mostly seems to work well!)
However, for my simpler example above, I used just one R process, and
a newly created empty SQLite database on a local disk - no NFS and no
concurrency at all. I think I forgot to mention it, but the segfault
from my other email also occurred in the strictly single process local
disk case.
--
Andrew Piskorski <a...@piskorski.com>
http://www.piskorski.com/
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