Re: Could postgres12 support millions of sequences? (like 10 million)

On Sun, Mar 22, 2020 at 6:58 PM David G. Johnston <
david(dot)g(dot)johnston(at)gmail(dot)com> wrote:

> On Sun, Mar 22, 2020 at 5:36 PM Christopher Browne <cbbrowne(at)gmail(dot)com>
> wrote:
>
>>
>> Then, on any of the tables where you need to assign sequence values,
>> you'd need to run an "after" trigger to do the assignment. The function
>> that finds the sequence value is kind of analagous:
>> create or replace function get_next_counter (i_group integer, i_element
>> integer) returns integer -- or bigint?
>> as $$
>> declare
>> c_seqname name;
>> c_query text;
>> c_seqval integer;
>> begin
>> c_seqname := 'obj_counter_' || i_group || '_' || i_element;
>> c_query := 'select nextval(' || quote_ident( c_seqname_ || ');';
>>
>
> or
>
> c_query := format('select nextval(%I);', c_seqname);
>
>> You're probably calling get_next_counter() millions of times, so perhaps
>> that code gets expanded directly into place in the trigger function.
>>
>
> not tested but something like:
>
> execute format('select nextval("obj_counter_%s_%s");', i_group, i_element)
> into strict c_seqval;
>
> or, more paranoidly:
>
> execute format('select nextval(%I);', format('obj_counter_%s_%s', i_group,
> i_element)) into strict c_seqval;
>
> David J.
>
>
I will add this to the previous solution.

Thank you all for all the ideas and suggestions.

I hope there will be int he future sequence data type and support and
optimizations of sequences in postgresql to deal with a lot of them. They
will be very useful no only for me :) but problems like monitoring and
counting things by the zillions.

Pablo