Re: Faster data load

On 2024-09-06 01:44:00 +0530, Lok P wrote:
> We are having a requirement to create approx 50 billion rows in a partition
> table(~1 billion rows per partition, 200+gb size daily partitions) for a
> performance test. We are currently using ' insert into <target table_partition>
> select.. From <source_table_partition> or <some transformed query>;' method .
> We have dropped all indexes and constraints First and then doing the load.
> Still it's taking 2-3 hours to populate one partition.

That seems quite slow. Is the table very wide or does it have a large
number of indexes?

> Is there a faster way to achieve this? 
> 
> Few teammate suggesting to use copy command and use file load instead, which
> will be faster.

I doubt that.

I benchmarked several strategies for populating tables 5 years ago and
(for my test data and on our hardware at the time - YMMV) s simple
INSERT ... SELECT was more than twice as fast as 8 parallel COPY
operations (and about 8 times as fast as a single COPY).

Details will have changed since then (I should rerun that benchmark on
a current system), but I'd be surprised if COPY became that much faster
relative to INSERT ... SELECT.

        hp

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