In a database which we are having we have nearly 100 tables, and in 75% of
the tables we have 6 columns ( INT ) as standard columns. What is standard
columns, if you create a table in this database you should have some default
6 columns in there they should maintain
1. who is the owner of that read
2. when it is added
3. who is updating the record
4. when it is updated .... and other columns....
OK, so your tables all have the same fields (columns), as if you used
CREATE TABLE new_table ( LIKE some_template_table ) ?
But many of the users are not doing anything with those columns, they are
all empty always....
meaning that they contain NULL values in that field for every record?
If you drop those columns we will gain any performance or not.....
The best way to find that out is to test it. I'd be surprised if it
didn't make *some* performance difference, but the question is whether
it will be enough to be worth caring about.
However, I recall hearing that PostgreSQL keeps a null bitmap and
doesn't use any storage for null fields. If that is correct then you
probably won't be paying much of a price in disk I/O, but there might
still be other costs.
I can't help wondering why you have all those useless columns in the
first place, and why you have so many identically structured tables.
--
Craig Ringer
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