> I'm a little confused by:
>
> $db->{LongReadLen}=some_number;
>
> This seems to me to effect insert and update but not read for text
> fields. Is that right?
>
Quite the opposite. It should not affect regular text (char, varchar)
fields at all, but only long, blob, memo etc.... and when it does, it
only affects the read, not the insert/update.
> What I really need to know is how setting this effects performance or
> resources used? (I'm trying to tweak a little more stability out of a
> high use website that was built on Access).
>
Um,(considerable self-censoring here) if the decision is yours to make,
consider moving the site to a database that was designed for a higher
number of users, such as mySQL. Access just isn't designed for that sort
of thing.
perldoc DBI
/LongReadLen
"LongReadLen" (unsigned integer, inherited)
This attribute may be used to control the maximum
length of long fields ("blob", "memo", etc.) which the
driver will read from the database automatically when
it fetches each row of data. The "LongReadLen"
attribute only relates to fetching and reading long
values; it is not involved in inserting or updating
them.
A value of 0 means not to automatically fetch any long
data. ("fetch" should return "undef" for long fields
when "LongReadLen" is 0.)
The default is typically 0 (zero) bytes but may vary
between drivers. Applications fetching long fields
should set this value to slightly larger than the
longest long field value to be fetched.
Some databases return some long types encoded as pairs
of hex digits. For these types, "LongReadLen" relates
to the underlying data length and not the doubled-up
length of the encoded string.
Changing the value of "LongReadLen" for a statement
handle after it has been "prepare"'d will typically
have no effect, so it's common to set "LongReadLen" on
the $dbh before calling "prepare".
Note that the value used here has a direct effect on
the memory used by the application, so don't be too
generous.
See "LongTruncOk" for more information on truncation
behavior.
On Fri, 2003-01-03 at 11:19, Jeff Thies wrote:
> Access DB on windows
>
> I'm a little confused by:
>
> $db->{LongReadLen}=some_number;
>
> This seems to me to effect insert and update but not read for text
> fields. Is that right?
>
> What I really need to know is how setting this effects performance or
> resources used? (I'm trying to tweak a little more stability out of a
> high use website that was built on Access).
>
> Jeff
>
