Philip Crotwell <crotwell@seis.sc.edu> writes:
> Is there significant overhead involoved in using large objects that aren't
> very large?
Yes, since each large object is a separate table in 7.0.* and before.
The allocation unit for table space is 8K, so your 10K objects chew up
16K of table space. What's worse, each LO table has a btree index, and
the minimum size of a btree index is 16K --- so your objects take 32K
apiece.
That accounts for a factor of 3. I'm not sure where the other 8K went.
Each LO table will require entries in pg_class, pg_attribute, pg_type,
and pg_index, plus the indexes on those tables, but that doesn't seem
like it'd amount to anything close to 8K per LO.
7.1 avoids this problem by keeping all LOs in one big table.
regards, tom lane