Re: Extensibility of the PostgreSQL wire protocol
Kuntal Ghosh <kuntalghosh.2007@gmail.com>
From: Kuntal Ghosh <kuntalghosh.2007@gmail.com>
To: Jan Wieck <jan@wi3ck.info>
Cc: Dave Cramer <davecramer@postgres.rocks>,
Robert Haas <robertmhaas@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, "Jonah H. Harris" <jonah.harris@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-02-19T09:36:41Z
Lists: pgsql-hackers
On Thu, Feb 18, 2021 at 9:32 PM Jan Wieck <jan@wi3ck.info> wrote:
>
And, here is how it looks with the following configuration:
telnet_srv.port = 1433
telnet_srv.listen_addresses = '*'
telnet localhost 1433
master
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
PostgreSQL Telnet Interface
database name: postgres
username: kuntal
password: changeme
> select 1;
?column?
----
1
SELECT 1
> select 1/0;
Message: ERROR - division by zero
Few comments in the extension code (although experimental):
1. In telnet_srv.c,
+ static int pe_port;
..
+ DefineCustomIntVariable("telnet_srv.port",
+ "Telnet server port.",
+ NULL,
+ &pe_port,
+ pe_port,
+ 1024,
+ 65536,
+ PGC_POSTMASTER,
+ 0,
+ NULL,
+ NULL,
+ NULL);
The variable pe_port should be initialized to a value which is > 1024
and < 65536. Otherwise, the following assert will fail,
TRAP: FailedAssertion("newval >= conf->min", File: "guc.c", Line:
5541, PID: 12100)
2. The function pq_putbytes shouldn't be used by anyone other than
old-style COPY out.
+ pq_putbytes(msg, strlen(msg));
Otherwise, the following assert will fail in the same function:
/* Should only be called by old-style COPY OUT */
Assert(DoingCopyOut);
--
Thanks & Regards,
Kuntal Ghosh
Amazon Web Services