Re: [Proposal] Fully WAL logged CREATE DATABASE - No Checkpoints

[Justin Pryzby]

On Wed, Aug 03, 2022 at 04:45:23PM +0530, Dilip Kumar wrote:
> Another version of the patch which closes the smgr at the end using
> smgrcloserellocator() and I have also added a commit message.

Thanks for providing a patch.
This seems to fix the second problem with accessing freed memory.

But I reproduced the first problem with a handful of tries interrupting the
while loop:

2022-08-03 10:39:50.129 CDT client backend[5530] [unknown] PANIC:  could not 
open critical system index 2662

In the failure, when trying to connect to the new "a" DB, it does this:

[pid 10700] openat(AT_FDCWD, "base/17003/pg_filenode.map", O_RDONLY) = 11
[pid 10700] read(11, 
"\27'Y\0\21\0\0\0\353\4\0\0\353\4\0\0\341\4\0\0\341\4\0\0\347\4\0\0\347\4\0\0\337\4\0\0\337\4\0\0\24\v\0\0\24\v\0\0\25\v\0\0\25\v\0\0K\20\0\0K\20\0\0L\20\0\0L\20\0\0\202\n\0\0\202\n\0\0\203\n\0\0\203\n\0\0\217\n\0\0\217\n\0\0\220\n\0\0\220\n\0\0b\n\0\0b\n\0\0c\n\0\0c\n\0\0f\n\0\0f\n\0\0g\n\0\0g\n\0\0\177\r\0\0\177\r\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\362\366\252\337",
 524) = 524
[pid 10700] close(11)                   = 0
[pid 10700] openat(AT_FDCWD, "base/17003/pg_internal.init", O_RDONLY) = -1 
ENOENT (No such file or directory)
[pid 10700] openat(AT_FDCWD, "base/17003/1259", O_RDWR) = 11
[pid 10700] lseek(11, 0, SEEK_END)      = 106496
[pid 10700] lseek(11, 0, SEEK_END)      = 106496

And then reads nothing but zero bytes from FD 11 (rel 1259/pg_class)

So far, I haven't succeeded in eliciting anything useful from valgrind.

-- 
Justin