pg_dump: NOTICE: ShmemAlloc: out of memory

I'm trying to dump a database called stocks. I did:

pg_dump stocks > stocks.sql
pg_dump: NOTICE: ShmemAlloc: out of memory pg_dump: Attempt to lock table
"slab" failed. ERROR: LockAcquire: holder table out of memory

I'm using postgresql-7.2.3-5.73 on RedHat 7.3

I'm trying to do some calculations on historical stock information. I have
written a Perl scrip that fills my database with historical stock
information off the web. This database has 3478 tables. One table for each
stock ticker I'm interested in. Each table has up to 3000 rows.

When I do my calculations I need stock info for many tickers on one date
and then the next date etc.

The fact that pg_dump crashes when I try and dump that data concerns me.

Have I set up a very poor database? Would it be better for me to put all
of my data in to one table? If the data is all in one table will I need to
do a select for each date and ticker on a table with 3478*3000 rows.