Στις 16/11/24 18:09, ο/η Adrian Klaver έγραψε:
On 11/16/24 03:15, Achilleas Mantzios wrote:
Στις 16/11/24 12:55, ο/η Max Ulidtko έγραψε:
Greetings, group!
I'm trying to understand a low-level issue. Am evaluating a new
client library for Postgres; it's not particularly popular /
mainstream, and as I've understood so far, sports an independent
implementation of PG binary protocol.
The issue I'm hitting with it is exemplified by server logs like this:
2024-11-16 10:28:19.927 UTC [46] LOG: statement: SET client_encoding
= 'UTF8';SET client_min_messages TO WARNING;
2024-11-16 10:28:19.928 UTC [46] LOG: execute <unnamed>: CREATE VIEW
public.foobar (alg, hash) AS VALUES ('md5', $1);
At least for SQL level prepared statements the statement has to be
one of :
|SELECT|, |INSERT|, |UPDATE|, |DELETE|, |MERGE|, or |VALUES|
|so CREATE is not valid, and I guess the extended protocol prepared
statements aint no different in this regard.
It would seem so. Using psycopg:
import psycopg
from psycopg import sql
con =
psycopg.connect("postgresql://postgres:postgres@127.0.0.1:5432/test")
cur = con.cursor()
cur.execute("CREATE VIEW public.foobar (alg, hash) AS VALUES ('md5',
%s)", ['test'])
IndeterminateDatatype: could not determine data type of parameter $1
cur.execute(sql.SQL("CREATE VIEW public.foobar (alg, hash) AS VALUES
('md5', {})").format(sql.Literal('test')))
con.commit()
cur.execute("select * from foobar")
cur.fetchone()
('md5', 'test')
I dont know python but this does not look like a solid prepared statement.
https://www.psycopg.org/psycopg3/docs/advanced/prepare.html
Does not seem to have used the prepared statement circuitry.
|
2024-11-16 10:28:19.928 UTC [46] DETAIL: parameters: $1 =
'test-param-value'
2024-11-16 10:28:19.928 UTC [46] ERROR: there is no parameter $1 at
character 57
Of course, I /am/ passing a value for parameter $1; and I can trace
that the client lib sends it out on the wire as expected. (Attaching
packet captures.)
Heck, even the PG server itself says, DETAIL: parameters: $1 =
'test-param-value' — so it sees the parameter! But then, immediately
unsees it.
Am I being hit by a PG bug? Is this a known issue?
I'd retested with master version of that client library, and against
6 latest major versions of PostgreSQL server (12 throughout to 17).
No difference across versions spotted; the result is consistently
error 42P02.
Is the client library doing something wrong? How can the server
claim there's no parameter $1 immediately after logging its value it
has received?
I did minify a 100-line SSCCE that reproduces the issue and can be
shared.
Any advice, or pointers on what to check next besides delving into
PG source, I'd greatly appreciate. Thanks in advance.
Max
