Re: Memory allocation error

Well. I think that I made significant advancement by thinking of how to
increase the functionality.
Adding a height of preceding must greater than the height of succeeding and
reduce the likelihood of infinity in recursion.
Regards, David

On Fri, 14 Jul 2023 at 12:54, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> wrote:

>
>
> pá 14. 7. 2023 v 13:13 odesílatel Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> napsal:
>
>> Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> writes:
>> > pá 14. 7. 2023 v 9:36 odesílatel Shaozhong SHI <shishaozhong(at)gmail(dot)com>
>> > napsal:
>> >> On Fri, 14 Jul 2023 at 08:14, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
>> >> wrote:
>> >>> It depends what you do. Postgres doesn't allow to allocate bigger
>> blocks
>> >>> than 1GB. Maybe you create too big string or too big value of some
>> other
>> >>> type. But it can be signal of some cache bloating.
>>
>> > The best way - do it all in one recursive query without any recursive
>> > function.
>> > This issue you can fix only by rewriting your code.
>>
>> Yeah, but nonetheless this error message is pretty user-unfriendly.
>>
>> The given example is too incomplete to run as-is, but I guessed that
>> maybe the array_agg() was accumulating too many values, and sure
>> enough it's possible to reproduce:
>>
>> regression=# select array_agg(x::text) from generate_series(1,100000000)
>> x;
>> ERROR: invalid memory alloc request size 1073741824
>>
>> We can do better than that. The attached patch causes the error to be
>>
>> regression=# select array_agg(x::text) from generate_series(1,100000000)
>> x;
>> ERROR: array size exceeds the maximum allowed (1073741823)
>>
>
> +1
>
> it is significantly better
>
> Regards
>
> Pavel
>
>>
>> I'm not wedded to that wording, but it's an existing translatable string
>> that at least points you in the direction of "my array is too big".
>> (This is also what you get if the eventual array construction overruns
>> the 1G limit, cf construct_md_array().)
>>
>> regards, tom lane
>>
>>