Tim Bunce wrote:
On Mon, May 12, 2008 at 05:15:34PM +0100, Martin Evans wrote:
Martin Evans wrote:
After seeing the recent posting by Greg Sabino Mullane in subject "Log DBI query and values with placeholders" I realised there was something else DBD::ODBC was out of date with - tracing.

DBD::ODBC does not implement its own trace flags but neither does it react to 'SQL' tracing. If I set trace('SQL') I can see the TraceLevel is set to 256 and I can find:

    sub parse_trace_flag {
        my ($h, $name) = @_;
        #      0xddDDDDrL (driver, DBI, reserved, Level)
        return 0x00000100 if $name eq 'SQL';
        return;
    }

in DBI. So to test if 'SQL' is enabled we:

if *DBIc_TRACE_LEVEL(imp_xxh) & 256) {blah;}
and also, how do I set this in Perl:

$dbh->{TraceLevel} = 'SQL|3';

DBI::db=HASH(0x82ba9d4) trace level set to 0x100/3 (DBI @ 0x0/0) in DBI 1.601-ithread (pid 4574)

$dbh->prepare(xxxx)
  here when I examine DBIc_TRACE_LEVEL(imp_dbh) it is 3!

Similarly if I use:

$h->trace($h->parse_trace_flags('SQL'))

What am I doing wrong? I'm a little confused by this since DBD::Pg seems to expect 'SQL' to work.

I presume you've read http://search.cpan.org/~timb/DBI/DBI.pm#TRACING

What's missing is an equivalent section in the DBI::DBD docs.
At the moment there's just a passing mention at the end of an unrelated section:
http://search.cpan.org/~timb/DBI/lib/DBI/DBD.pm#The_dbd_drv_error_method

The short answer is that DBIc_TRACE_LEVEL only gives you the 'trace
level' not the 'trace flags' (which you can get via DBIc_TRACE_FLAGS).

You probably want to use the fancy DBIc_TRACE macros though...

Hopefully this chunk of DBIXS.h with help:

#define DBIc_TRACE_LEVEL_MASK   0x0000000F
#define DBIc_TRACE_FLAGS_MASK   0xFFFFFF00
#define DBIc_TRACE_SETTINGS(imp) (DBIc_DBISTATE(imp)->debug)
#define DBIc_TRACE_LEVEL(imp)   (DBIc_TRACE_SETTINGS(imp) & 
DBIc_TRACE_LEVEL_MASK)
#define DBIc_TRACE_FLAGS(imp)   (DBIc_TRACE_SETTINGS(imp) & 
DBIc_TRACE_FLAGS_MASK)
/* DBIc_TRACE_MATCHES(this, crnt): true if this 'matches' (is within) crnt
   DBIc_TRACE_MATCHES(foo, DBIc_TRACE_SETTINGS(imp))
*/
#define DBIc_TRACE_MATCHES(this, crnt)  \
        (  ((crnt & DBIc_TRACE_LEVEL_MASK) >= (this & DBIc_TRACE_LEVEL_MASK)) \
        || ((crnt & DBIc_TRACE_FLAGS_MASK)  & (this & DBIc_TRACE_FLAGS_MASK)) )
/* DBIc_TRACE: true if flags match & DBI level>=flaglevel, or if DBI level>level
   This is the main trace testing macro to be used by drivers.
   (Drivers should define their own DBDtf_* macros for the top 8 bits: 
0xFF000000)
   DBIc_TRACE(imp,         0, 0, 4) = if level >= 4
   DBIc_TRACE(imp, DBDtf_FOO, 2, 4) = if tracing DBDtf_FOO & level>=2 or 
level>=4
   DBIc_TRACE(imp, DBDtf_FOO, 2, 0) = as above but never trace just due to level
*/
#define DBIc_TRACE(imp, flags, flaglevel, level)        \
        (  (flags && (DBIc_TRACE_FLAGS(imp) & flags) && (DBIc_TRACE_LEVEL(imp) 
>= flaglevel)) \
        || (level && DBIc_TRACE_LEVEL(imp) >= level) )

Patches to DBI::DBD very welcome.

Tim.



Thanks Tim,

I've got the gist of that now and implemented in DBD::ODBC.
Patch for DBI::DBD on its way in the next few days.

Martin
--
Martin J. Evans
Easysoft Limited
http://www.easysoft.com

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