Re: pg_receivewal.exe unhandled exception in zlib1.dll

Hi,

On 2022-02-11 16:33:11 +0100, Juan José Santamaría Flecha wrote:
> If you execute pg_receivewal.exe with the option "--compression-method
> gzip" it will fail with no error. You can see an error in the db log:
>
> 2022-02-10 11:46:32.725 CET [11664][walsender] [pg_receivewal][3/0:0] LOG:
> could not receive data from client: An existing connection was forcibly
> closed by the remote host.
>
> Tracing the execution you can see:
>
> Unhandled exception at 0x00007FFEA78C1208 (ucrtbase.dll) in An invalid
> parameter was passed to a function that considers invalid parameters fatal.
> ucrtbase.dll!00007ff8e8ae36a2() Unknown
> > zlib1.dll!gz_comp(gz_state * state, int flush) Line 111 C
> zlib1.dll!gz_write(gz_state * state, const void * buf, unsigned __int64
> len) Line 235 C
> pg_receivewal.exe!dir_write(void * f, const void * buf, unsigned __int64
> count) Line 300 C
> pg_receivewal.exe!ProcessXLogDataMsg(pg_conn * conn, StreamCtl * stream,
> char * copybuf, int len, unsigned __int64 * blockpos) Line 1150 C
> pg_receivewal.exe!HandleCopyStream(pg_conn * conn, StreamCtl * stream,
> unsigned __int64 * stoppos) Line 850 C
> pg_receivewal.exe!ReceiveXlogStream(pg_conn * conn, StreamCtl * stream)
> Line 605 C
> pg_receivewal.exe!StreamLog() Line 636 C
> pg_receivewal.exe!main(int argc, char * * argv) Line 1005 C
>
> The problem comes from the file descriptor passed to gzdopen() in
> 'src/bin/pg_basebackup/walmethods.c'. Using gzopen() instead, solves the
> issue without ifdefing for WIN32. Please find attached a patch for so.

I hit this as well. The problem is really caused by using a debug build of
postgres vs a production build of zlib. The use different C runtimes, with
different file descriptors. A lot of resources in the windows world are
unfortunately tied to the C runtime and that there can multiple C runtimes in
a single process.

Greetings,

Andres Freund