Re: MyISAM vs InnoDB

[Jochem van Dieten]

On 11/1/06, mos wrote:
> At 02:27 PM 11/1/2006, Jochem van Dieten wrote:
>>
>> What is the big deal of a TB? Now, if you get past 20 TB you might
>> want to team up with one of the commercial PostgreSQL supporters
>> (Fujitsu, EnterpriseDB, Greenplum etc.), but Sun even sells appliances
>> for 100 TB PostgreSQL databases.
>
>          There is a big difference between a 20 TB database and a 20 TB
> table!  Unless you're storing huge blobs, a table of over 1TB will have
> hundreds of millions of rows (billions?), and that means huge index trees
> that need to be maintained.

Indexes scale with ln(O). The difference between 100 million rows and
1 billion rows is maybe 10%. And if you are worried about your indexes
getting asymmetric use a hash index instead of a B-tree. Though
realistically you would partition the data and then your indexes get
partitioned too.


> If PostgreSQL can put 20 TB into a table and
> still have reasonably fast inserts and queries, then I'll take my hat off
> to them.

It can if you design your queries to make use of the indexes and the
partitioning.


> But first I need to see proof that they can accomplish this. So if
> you have any sites or white papers you'd like to share, go ahead. Keep in
> mind we're talking about TB tables here, not databases.

Google the PostgreSQL and PostGIS mailinglists.

Jochem