RE: Copy data to DSA area

Hi, Thomas

>-----Original Message-----
>From: Thomas Munro [mailto:thomas(dot)munro(at)gmail(dot)com]
>Subject: Re: Copy data to DSA area
>
>On Wed, May 8, 2019 at 5:29 PM Ideriha, Takeshi <ideriha(dot)takeshi(at)jp(dot)fujitsu(dot)com>
>wrote:
>> >From: Ideriha, Takeshi [mailto:ideriha(dot)takeshi(at)jp(dot)fujitsu(dot)com]
>> >Sent: Friday, April 26, 2019 11:50 PM Well, after developing PoC, I
>> >realized that this PoC doesn't solve the local process is crashed
>> >before the context becomes shared because local process keeps track
>> >of pointer to chunks.
>> >Maybe all of you have already noticed and pointed out this case :) So
>> >it needs another work but this poc is a good step for me to advance more.
>>
>> I think the point to prevent memory leak is allocating memory and
>> storing its address into a structure at the same time. This structure
>> should be trackable from other process.
>
>I'm not sure that it's necessarily wrong to keep tracking information in private memory.
>If any backend crashes, the postmaster will terminate all backends and reinitialise
>everything anyway, because shared memory might be corrupted.

Thank you very much for the clarification. I haven't looked into reinitialize sequence
so much. I checked CreateSharedMemoryAndSemaphores is called again and shared
memory gets initialized. So I'm going to put keep tracking information in private
memory and send a patch.

Regards,
Takeshi Ideriha