I would work on this and try to present the performance test results. I would also go ahead and examine, whether the logic can be added into heap_form_tuple by any means.
Thanks, Gokul. On Wed, Mar 19, 2008 at 12:11 AM, Bruce Momjian <[EMAIL PROTECTED]> wrote: > > Added to TODO: > > * Consider not storing a NULL bitmap on disk if all the NULLs are > trailing > > http://archives.postgresql.org/pgsql-hackers/2007-12/msg00624.php > http://archives.postgresql.org/pgsql-patches/2007-12/msg00109.php > > Tom's comments are: > > What this lacks is some performance testing to measure the cost of > the > extra tests in heap_form_tuple. If that can be shown to be > negligible > then it's probably worth doing .... though I don't like any part of > the > actually submitted patch ;-). All this should need is a bit more > logic > in heap_form_tuple and heap_formtuple. > > > --------------------------------------------------------------------------- > > Gokulakannan Somasundaram wrote: > > Hi, > > Currently we check for the existence of NULL values in the tuple and > we > > set the has_null flag. If the has_null flag is present, the tuple will > be > > storing a null bitmap. What i propose is > > > > a) By modifying the functions, heap_form_tuple and heap_fill_tuple, we > can > > check whether all the nulls are trailing nulls. If all the nulls are > > trailing nulls, then we will not set the has_null flag and we will not > have > > the null bitmap with the tuple. > > > > b) While selecting the tuple, we will check whether the tuple offset > equals > > / exceeds the length of the tuple and then mark the remaining attributes > of > > the tuple as null. To be exact, we need to modify the slot_deform_tuple > in > > order to achieve the same. > > > > This may not give huge performance benefits, but as you may know, it > will > > help is reducing the disk footprint. > > > > > > Expecting your comments.. > > > > -- > > Thanks, > > Gokul. > > CertoSQL Project, > > Allied Solution Group. > > (www.alliedgroups.com) > > -- > Bruce Momjian <[EMAIL PROTECTED]> http://momjian.us > EnterpriseDB http://postgres.enterprisedb.com > > + If your life is a hard drive, Christ can be your backup. + > > -- > Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-hackers >
