fastapi-sqlalchemy-pg-catalog: clarify simple-Query semantics on parameterized SQL

Copilot review noted (correctly) that the README + main.py docstring
described the pg_class probe as "parameter-less SQL", which conflicts
with the recorded mock carrying 7 bind values. psycopg2 in fact uses
the simple-Query protocol even when the source SQL is parameterized:
it substitutes %(param)s placeholders client-side and emits the
resulting inlined SQL as a single Q packet (no Bind/Execute frames).
The bind values exist at the application layer; the wire shape is
simple-Query.

Both docs now say so explicitly so a reader doesn't see the recorded
bind-value list and conclude the wire path must be extended-Query.

Signed-off-by: Akash Kumar <meakash7902@gmail.com>

Author: AkashKumar7902

fastapi-sqlalchemy-pg-catalog/README.md

@@ -8,8 +8,14 @@ asymmetry (keploy/integrations#193).
 
 At app boot, SQLAlchemy's `Base.metadata.create_all(engine)` issues a
 `pg_catalog.pg_class` probe per declared table to decide whether to
-skip `CREATE TABLE`. With psycopg2 + parameter-less SQL the probe
-goes through the **simple-query** protocol path.
+skip `CREATE TABLE`. psycopg2 sends the probe over the
+**simple-query** protocol (`Q` packet) even though the source SQL is
+parameterized — it substitutes the `%(param)s` placeholders
+client-side and emits the resulting inlined SQL as a single
+statement, with no `Bind`/`Execute` frames. So the wire shape is
+simple-Query carrying inlined bind values; the recorded mock keeps
+the parameter list for matching, but the dispatcher's classifier
+sees a simple-Query CATALOG request.
 
 In `pkg/postgres/v3/replayer/dispatcher/dispatcher.go`:
 

fastapi-sqlalchemy-pg-catalog/app/main.py

@@ -4,11 +4,17 @@
 ``Base.metadata.create_all`` table-existence probe.
 
 Boot sequence:
-  1. SQLAlchemy creates an engine over psycopg2 (simple-query for
-     parameter-less SQL).
+  1. SQLAlchemy creates an engine over psycopg2. psycopg2 sends queries
+     via the simple-Query protocol (``Q`` packet) even when the source
+     SQL is parameterized: it does client-side ``%(param)s`` substitution
+     and emits the resulting string as a single inlined statement
+     (no ``Bind``/``Execute`` frames).
   2. ``Base.metadata.create_all(engine)`` issues one
      ``SELECT pg_catalog.pg_class.relname ...`` probe per declared table
-     to decide whether each ``CREATE TABLE`` should be skipped.
+     to decide whether each ``CREATE TABLE`` should be skipped. The
+     probe SQL has 7 parameters (table name, relkind chars, namespace);
+     psycopg2 inlines them before the wire write, so the dispatcher sees
+     a simple-Query statement that classifies as ``ClassCatalog``.
   3. FastAPI starts serving requests.
 
 The probe is what hits the dispatcher's ``case match.ClassCatalog``