Initial implementation of pgvector and Oracle 26ai vector search demo

Three FastAPI backends comparing PostgreSQL/pgvector and Oracle 26ai for
semantic image search using CLIP embeddings: Python-side embedding for both
databases, plus Oracle in-database embedding via VECTOR_EMBEDDING(CLIP_TXT).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
2026-05-19 11:33:16 +02:00
commit 66f7db40b0
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import os
import oracledb
from dotenv import load_dotenv
load_dotenv()
def get_connection():
return oracledb.connect(
user=os.getenv("ORA_USER"),
password=os.getenv("ORA_PASSWORD"),
dsn=f"{os.getenv('ORA_HOST')}:{os.getenv('ORA_PORT')}/{os.getenv('ORA_SERVICE')}",
)
def get_connection_indb():
return oracledb.connect(
user=os.getenv("ORA_USER_INDB"),
password=os.getenv("ORA_PASSWORD_INDB"),
dsn=f"{os.getenv('ORA_HOST')}:{os.getenv('ORA_PORT')}/{os.getenv('ORA_SERVICE')}",
)
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from sentence_transformers import SentenceTransformer
from PIL import Image
_model = None
def _get_model():
global _model
if _model is None:
_model = SentenceTransformer("clip-ViT-B-32")
return _model
def embed_image(path: str) -> list[float]:
img = Image.open(path).convert("RGB")
return _get_model().encode(img).tolist()
def embed_text(text: str) -> list[float]:
return _get_model().encode(text).tolist()
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import os
import array
from dotenv import load_dotenv
from db_oracle import get_connection
from embedder import embed_image
load_dotenv()
PHOTOS_DIR = os.getenv("PHOTOS_DIR")
CREATE_TABLE = """
CREATE TABLE images (
id NUMBER GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
filename VARCHAR2(255) NOT NULL UNIQUE,
filepath VARCHAR2(1000) NOT NULL,
embedding VECTOR(512, FLOAT32)
)
"""
CREATE_INDEX = """
CREATE VECTOR INDEX images_embedding_idx
ON images(embedding)
ORGANIZATION INMEMORY NEIGHBOR GRAPH
WITH DISTANCE COSINE
WITH TARGET ACCURACY 95
PARAMETERS (type HNSW, neighbors 32, efconstruction 200)
"""
INSERT = "INSERT INTO images (filename, filepath, embedding) VALUES (:1, :2, :3)"
def table_exists(cur):
cur.execute("SELECT COUNT(*) FROM user_tables WHERE table_name = 'IMAGES'")
return cur.fetchone()[0] > 0
def main():
conn = get_connection()
cur = conn.cursor()
if not table_exists(cur):
cur.execute(CREATE_TABLE)
cur.execute(CREATE_INDEX)
conn.commit()
print("Table and index created.")
else:
print("Table already exists, skipping creation.")
files = [f for f in os.listdir(PHOTOS_DIR) if f.lower().endswith((".jpg", ".jpeg"))]
print(f"Found {len(files)} photos in {PHOTOS_DIR}")
for i, filename in enumerate(files, 1):
filepath = os.path.join(PHOTOS_DIR, filename)
cur.execute("SELECT 1 FROM images WHERE filename = :1", (filename,))
if cur.fetchone():
print(f"[{i}/{len(files)}] Skipping {filename} (already indexed)")
continue
embedding = array.array("f", embed_image(filepath))
cur.execute(INSERT, (filename, filepath, embedding))
conn.commit()
print(f"[{i}/{len(files)}] Indexed {filename}")
cur.close()
conn.close()
print("Done.")
if __name__ == "__main__":
main()
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import os
import array
from fastapi import FastAPI, Query
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import FileResponse
from dotenv import load_dotenv
from db_oracle import get_connection
from embedder import embed_text
load_dotenv()
PHOTOS_DIR = os.getenv("PHOTOS_DIR")
app = FastAPI()
app.add_middleware(CORSMiddleware, allow_origins=["*"], allow_methods=["*"], allow_headers=["*"])
@app.get("/search")
def search(q: str = Query(...), limit: int = Query(12)):
vec = array.array("f", embed_text(q))
conn = get_connection()
cur = conn.cursor()
cur.execute(
"""
SELECT filename, 1 - VECTOR_DISTANCE(embedding, :vec, COSINE) AS score
FROM images
ORDER BY VECTOR_DISTANCE(embedding, :vec, COSINE)
FETCH FIRST :lim ROWS ONLY
""",
{"vec": vec, "lim": limit},
)
rows = cur.fetchall()
cur.close()
conn.close()
return [{"filename": r[0], "score": round(r[1], 4)} for r in rows]
@app.get("/stats")
def stats():
conn = get_connection()
cur = conn.cursor()
cur.execute("SELECT COUNT(*) FROM images")
count = cur.fetchone()[0]
cur.close()
conn.close()
return {"count": count}
@app.get("/photos/{filename}")
def get_photo(filename: str):
path = os.path.join(PHOTOS_DIR, filename)
return FileResponse(path, media_type="image/jpeg")
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import os
from fastapi import FastAPI, Query
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import FileResponse
from dotenv import load_dotenv
from db_oracle import get_connection_indb
load_dotenv()
PHOTOS_DIR = os.getenv("PHOTOS_DIR")
app = FastAPI()
app.add_middleware(CORSMiddleware, allow_origins=["*"], allow_methods=["*"], allow_headers=["*"])
@app.get("/search")
def search(q: str = Query(...), limit: int = Query(12)):
conn = get_connection_indb()
cur = conn.cursor()
cur.execute(
"""
SELECT filename,
1 - VECTOR_DISTANCE(
foto_vek,
VECTOR_EMBEDDING(CLIP_TXT USING :q AS data),
COSINE
) AS score
FROM VECTOR.FOTO_VEKTOR
ORDER BY VECTOR_DISTANCE(
foto_vek,
VECTOR_EMBEDDING(CLIP_TXT USING :q AS data),
COSINE
)
FETCH FIRST :lim ROWS ONLY
""",
{"q": q, "lim": limit},
)
rows = cur.fetchall()
cur.close()
conn.close()
return [{"filename": r[0], "score": round(r[1], 4)} for r in rows]
@app.get("/stats")
def stats():
conn = get_connection_indb()
cur = conn.cursor()
cur.execute("SELECT COUNT(*) FROM VECTOR.FOTO_VEKTOR")
count = cur.fetchone()[0]
cur.close()
conn.close()
return {"count": count}
@app.get("/photos/{filename}")
def get_photo(filename: str):
path = os.path.join(PHOTOS_DIR, filename)
return FileResponse(path, media_type="image/jpeg")