Re: Load experimentation

Ben Brehmer wrote:
> Thanks for the quick responses. I will respond to all questions in one
> email:
>
> By "Loading data" I am implying: "psql -U postgres -d somedatabase -f
> sql_file.sql". The sql_file.sql contains table creates and insert
> statements. There are no indexes present nor created during the load.

Although transactions of over 1000 INSERT statements don't speed things up much, they don't hurt either, especially on a new system that nobody is using yet. Since you're loading from big SQL files using psql, just put a "begin;" at the top of the file and a "commit;" at the bottom. Unlike Oracle, Postgres even allows CREATE and such to be done inside a transaction.

And BTW, don't forget to ANALYZE when you're all done.

Craig

>
> OS: x86_64-unknown-linux-gnu, compiled by GCC gcc (GCC) 4.1.2 20080704
> (Red Hat 4.1.2-44)
>
> PostgreSQL: I will try upgrading to latest version.
>
> COPY command: Unfortunately I'm stuck with INSERTS due to the nature
> this data was generated (Hadoop/MapReduce).
>
> Transactions: Have started a second load process with chunks of 1000
> inserts wrapped in a transaction. Its dropped the load time for 1000
> inserts from 1 Hour to 7 minutes :)
>
> Disk Setup: Using a single disk Amazon image for the destination
> (database). Source is coming from an EBS volume. I didn't think there
> were any disk options in Amazon?
>
>
> Thanks!
>
> Ben
>
>
>
>
>
> On 07/12/2009 10:39 AM, Thom Brown wrote:
>> 2009/12/7 Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov
>> <mailto:Kevin(dot)Grittner(at)wicourts(dot)gov>>
>>
>> Ben Brehmer <benbrehmer(at)gmail(dot)com <mailto:benbrehmer(at)gmail(dot)com>>
>> wrote:
>>
>> > -7.5 GB memory
>> > -4 EC2 Compute Units (2 virtual cores with 2 EC2 Compute Units
>> > each)
>> > -64-bit platform
>>
>> What OS?
>>
>> > (PostgreSQL 8.1.3)
>>
>> Why use such an antiquated, buggy version? Newer versions are
>> faster.
>>
>> -Kevin
>>
>>
>>
>> I'd agree with trying to use the latest version you can.
>>
>> How are you loading this data? I'd make sure you haven't got any
>> indices, primary keys, triggers or constraints on your tables before
>> you begin the initial load, just add them after. Also use either the
>> COPY command for loading, or prepared transactions. Individual insert
>> commands will just take way too long.
>>
>> Regards
>>
>> Thom