Re: WAL segment file descriptor leak on read errors can PANIC the server

On Mon, Oct 5, 2026 at 10:20 AM Bertrand Drouvot <
bertranddrouvot(dot)pg(at)gmail(dot)com> wrote:

> Worth mentioning that this is intended for descriptors not managed by
> another
> cleanup mechanism, such as those returned by BasicOpenFile()? Otherwise,
> using
> it with OpenTransientFile() could result in segment_close() being called
> with a
> stale descriptor.
>

BasicOpenFile() called repeatedly will accumulate stale descriptors
indefinitely.

int
BasicOpenFile(const char *fileName, int fileFlags)
{
return BasicOpenFilePerm(fileName, fileFlags, pg_file_create_mode);
}

int
BasicOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode)

{

int fd;

fd = open(fileName, fileFlags & ~PG_O_DIRECT, fileMode);

if (fd >= 0)

{

return fd; /* success! */

While
PathNameOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode)

Is tracked by a LRU list, and the number of open files in that list is
capped.

I wrote about a potential relation with this before in
https://www.postgresql.org/message-id/CAE8JnxOyYyv6m%3DMz%2BNwQb%3DQj6yFkXD2a%2Bn%3D%2BNes6mhmH6L5PoQ%40mail.gmail.com

Regards,
Alexandre