> Return Values
> Returns TRUE on success or FALSE on failure. Returns string if
> PGSQL_DML_STRING is passed via options.
I have found in my copy of PHP (version 4.4.0) that if you use the 'PGSQL_DML_STRING' option, the function does not execute any query. It merely returns the query which would have been executed.
Another thing I noticed, pg_update does not seem to make use of pg_trace (atleast in 4.4.0).
PS this isn't a bug report, just an explanation of some undocumented features I noticed. As the manual says, the function is still in development so this behaviour may differ from version to version.