Regarding use case of epoch to generate nanoseconds precision

On Wed, May 22, 2024 at 4:21 AM Durgamahesh Manne <maheshpostgres9@gmail.com>
wrote:

Hi

Postgres supports only upto microseconds (6 decimal precision).
How do we generate timestamp with nanoseconds as rds postgres not
supported timestamp9 extension ?
Is there a way to generate timestamp with nanoseconds precision on
pg_partman with epoch without typecasting or with typecasting ?

p_epoch => (to_timestamp(control column))
Here what is the control column?
How to run it with the create_parent function of partman?

Here as per the pg_partman doc
p_epoch - tells pg_partman that the control column is an integer type, but
actually represents an epoch time value. Valid values for this option are:
'seconds', 'milliseconds', 'nanoseconds', and 'none'. The default is
'none'. All table names will be time-based. In addition to a normal index
on the control column, be sure you create a functional, time-based index on
the control column (to_timestamp(control column)) as well so this works
efficiently.

Not a postgresql expert but - - - I'm wondering how you actually plan to
implement this nanosecond timestamp?
You will be working in an area where you will need some extreme corner case
equipment for all items in the system.
Not saying that measurements in this area can't be done rather that you
will have internal ambiguities in your
accuracy (network timing for one at the very least).

Good luck

On Wed, May 22, 2024 at 5:21 AM Durgamahesh Manne <maheshpostgres9@gmail.com>
wrote:

Hi

Postgres supports only upto microseconds (6 decimal precision).
How do we generate timestamp with nanoseconds as rds postgres not
supported timestamp9 extension ?
Is there a way to generate timestamp with nanoseconds precision on
pg_partman with epoch without typecasting or with typecasting ?

p_epoch => (to_timestamp(control column))
Here what is the control column?
How to run it with the create_parent function of partman?

Here as per the pg_partman doc
p_epoch - tells pg_partman that the control column is an integer type, but
actually represents an epoch time value. Valid values for this option are:
'seconds', 'milliseconds', 'nanoseconds', and 'none'. The default is
'none'. All table names will be time-based. In addition to a normal index
on the control column, be sure you create a functional, time-based index on
the control column (to_timestamp(control column)) as well so this works
efficiently.

Regards,
Durga Mahesh Manne

The option in pg_partman simply multiples the normal epoch value by
1000000000 then converts it with to_timestamp().

https://github.com/pgpartman/pg_partman/blob/master/sql/functions/create_partition_time.sql#L119C64-L119C74

I'd already had the millisecond option in partman for epoch, and someone
requested nanosecond precision. It was easy to add the option so I did it
for them, and anyone else that may find it useful. How you actually
implement that level of time precision in an epoch value in your
environment is entirely up to you.

--
Keith Fiske
Senior Database Engineer
Crunchy Data - http://crunchydata.com