Andy <angelflow@yahoo.com> writes:
> Are there any reasons why table & index sizes of Postgresql should be larger than MySQL?
Well, the per-row headers in PG are definitely bigger because of MVCC
requirements. It's hard to speculate much about index sizes with
no information about the table/index schemas.
> The company in the presentation used Postgresql 8.1. Has there been any significant changes in data size between 8.1
and8.4/9.0?
Well, we shaved 4 bytes off the tuple header size since 8.1, and there's
been work on cutting per-field overhead too, and there's now some
ability to control fillfactor in indexes. But there's really not enough
information here to say how much difference this might've made for them.
regards, tom lane