diff --git a/pica-etherpad-db/Dockerfile b/pica-etherpad-db/Dockerfile
index 40f99a97ce98e5ea33a2f56adb38670beb66809d..f0cd6ca670c75ba817777f5b60e21e50f834c956 100644
--- a/pica-etherpad-db/Dockerfile
+++ b/pica-etherpad-db/Dockerfile
@@ -7,6 +7,7 @@ COPY config/myisam_perf.cnf /etc/mysql/conf.d/myisam_perf.cnf
 # the container. But mysql refuses to use config files that are world-
 # writable, so we have to change those permissions:
 RUN chmod 644 /etc/mysql/conf.d/binary_log.cnf
+RUN chmod 644 /etc/mysql/conf.d/myisam_perf.cnf
 
 # Remove unnecessary tools
 # This removes the following packages: