Re: Problems with MemoryContextSwitchTo ()

čt 17. 9. 2020 v 3:16 odesílatel Yessica Brinkmann <
brinkmann(dot)yessica(at)gmail(dot)com> napsal:

> Good night,
> Thank you very much for the answer.
> Excuse me please just answered, I was at my job.
> And yes, I get the results of the list with SPI_exec.
> And I am also using SPI_finish (). But I save the results of the previous
> query in the array idxcd-> varattnnames.
> And in the second foreach it should print me the values that I got in the
> query, since I print the values of idxcd-> varattnnames, but it is printing
> null.
> And I think the memory context switch is fine too, so I really don't know
> why it prints null to me.
> I will greatly appreciate a help please. I can't really understand why it
> prints null in the second foreach, even though I already tried various
> changes.
>

do you use Postgres with active assertions ?

postgres=# show debug_assertions ;
┌──────────────────┐
│ debug_assertions │
╞══════════════════╡
│ on │
└──────────────────┘
(1 row)

maybe you somewhere allocate less memory then it is necessary and some
memset rewrites memory with your data. When you have a problem with memory,
then you should to very carefully check a) if memory is allocated in good
context, b) if memory was allocated enough (sometimes I just allocated x +
100000 for testing).

Can you write a reproducer ? code that I can check at my home. Postgres is
pretty complex system, and it is hard to fix some issue without access to
code

Best regards,
> Yessica Brinkmann
>
> El mié., 16 sept. 2020 a las 9:16, Pavel Stehule (<pavel(dot)stehule(at)gmail(dot)com>)
> escribió:
>
>>
>>
>> st 16. 9. 2020 v 15:09 odesílatel Yessica Brinkmann <
>> brinkmann(dot)yessica(at)gmail(dot)com> napsal:
>>
>>> Well, the fact is that I have a function called get_columnnames, which
>>> in the second foreach, is printing the values of idxcd-> varattnnames [i]
>>> the null value. This is the error.
>>
>>
>> How you get this list? It is result of SPI_exec*** ?
>>
>> There is SPI_finish(), that cleaning a memory used by SPI interface, and
>> theoretically it can clean result of previous query.
>>
>> Regards
>>
>> Pavel
>>
>>
>>>
>>> -------- Mensaje original --------
>>> Asunto: Re: Problems with MemoryContextSwitchTo ()
>>> De: Pavel Stehule
>>> Para: Yessica Brinkmann
>>> CC: pgsql-general
>>>
>>>
>>>
>>>
>>> st 16. 9. 2020 v 13:32 odesílatel Yessica Brinkmann <
>>> brinkmann(dot)yessica(at)gmail(dot)com> napsal:
>>>
>>>> Good Morning.
>>>> I will greatly appreciate a help please on this subject. I actually
>>>> did several tests already and tried a lot to fix it myself. But I am
>>>> not able to. And I really need to know this in order to finish my
>>>> university thesis. If someone can help me please.
>>>> Best regards,
>>>> Yessica Brinkmann
>>>>
>>>
>>> please, can you attach your code, and can you show the error message?
>>>
>>> It is hard to say what is the problem from your mail?
>>>
>>> Regards
>>>
>>> Pavel
>>>
>>>
>>>
>>>>
>>>> El mié., 16 sept. 2020 a las 0:42, Yessica Brinkmann (<
>>>> brinkmann(dot)yessica(at)gmail(dot)com>) escribió:
>>>>
>>>>>
>>>>>
>>>>> Hello.
>>>>> I think several of you will already remember me. I'm the one with the
>>>>> IndexAdviser topic. Only that I changed my email address.
>>>>> As you may recall, I am doing my thesis on the subject of IndexAdviser
>>>>> modifications.
>>>>> I really appreciate the help they have given me in various Postgresql
>>>>> groups.
>>>>> Well, I was really nearing the end of the programming part of the
>>>>> thesis, when I had a problem to be able to compile my program in a moment,
>>>>> and by accident some lines of source code were moved.
>>>>> And for this reason, I think I have problems again with the context
>>>>> switch issue, since at some point my context switch stopped working for me,
>>>>> I think because of the issue that some lines of source code were moved.
>>>>> Well, the fact is that I have a function called get_columnnames, which
>>>>> in the second foreach, is printing the values of idxcd-> varattnnames [i]
>>>>> the null value.
>>>>> This second foreach, I only do it to test if the data is really saved
>>>>> well and if I can recover it properly.
>>>>> And since the data is not retrieved properly, or is not saved
>>>>> properly, in the following functions of my program, the value of idxcd->
>>>>> varattnnames [i] continues to appear as null.
>>>>> I will appreciate a lot please help, if you can tell me please why the
>>>>> function prints null in the values of idxcd-> varattnnames [i], in the
>>>>> second foreach, if it is due to an error in the context switch, or why it
>>>>> could be .
>>>>>
>>>>> I send my function as an attachment.
>>>>>
>>>>>
>>>>> Best regards,
>>>>> Yessica Brinkmann.
>>>>>
>>>>