diff --git a/tests/Dockerfile.pagila b/tests/Dockerfile.pagila
index d0016165..1874d0fe 100644
--- a/tests/Dockerfile.pagila
+++ b/tests/Dockerfile.pagila
@@ -44,7 +44,11 @@ RUN apt-get update \
   && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /usr/src/
-RUN git clone --depth 1 https://github.com/devrimgunduz/pagila.git
+# pinned to pagila v3.1.0 @ fef9675 (immutable SHA; v4 needs PG18 + pgvector)
+RUN git init -q pagila \
+  && git -C pagila remote add origin https://github.com/devrimgunduz/pagila.git \
+  && git -C pagila fetch -q --depth 1 origin fef9675714cfba1756df4719b5e36075a7ddf90e \
+  && git -C pagila checkout -q FETCH_HEAD
 
 #RUN adduser --disabled-password --gecos '' --home /var/lib/postgres docker
 #RUN adduser docker sudo