Question

I have a table like this :

create table stream_last
(
        symbol_id       integer,
        high            decimal(8,2),
        low             decimal(8,2),
        last            decimal(8,2),
        volume          integer,
        last_updated    datetime,
        INDEX USING BTREE(symbol_id)
) ENGINE=MEMORY;

I need to do about 4,000 inserts every 5 seconds (blasted in by a C program reading a stream and aggregating on symbol_id). However, I could sort the data first and insert in order by symbol_id ASCENDING. would that make this bulk insert faster?

a secondary question would be, is BTREE the best option here for index? From the documentation, I could have used HASH but wasn’t sure which would be best…

Don

Answer 1

Don’t think you may gain any significant difference with the optimisation you’ve proposed, but advises listed here

http://dev.mysql.com/doc/refman/5.0/en/insert-speed.html

may certainly help you understand better your needs.

This quote may have sense

The size of the table slows down the insertion of indexes by log N,
assuming B-tree indexes.

You can use the following methods to speed up inserts:

If you are inserting many rows from the same client at the same time,
use INSERT statements with multiple VALUES lists to insert several
rows at a time. This is considerably faster (many times faster in some
cases) than using separate single-row INSERT statements. If you are
adding data to a nonempty table, you can tune the
bulk_insert_buffer_size variable to make data insertion even faster.
See Section 5.1.3, “Server System Variables”.