feat(clamav): reduce RAM usage via ConcurrentDatabaseReload no and MaxThreads 2 (#7972)

Containers/clamav/Dockerfile

@@ -13,6 +13,15 @@ RUN set -ex; \
     sed -i "s|#\?PCREMaxFileSize.*|PCREMaxFileSize 2000M|g" /etc/clamav/clamd.conf; \
 # StreamMaxLength must be synced with av_stream_max_length inside the Nextcloud files_antivirus plugin
     sed -i "s|#\?StreamMaxLength.*|StreamMaxLength 2000M|g" /etc/clamav/clamd.conf; \
+# By default clamd keeps the old signature database in RAM while loading the new one,
+# briefly doubling memory usage (~1 GB extra) during each freshclam update cycle.
+# Setting ConcurrentDatabaseReload to "no" makes clamd unload the old database first,
+# eliminating that transient peak and significantly reducing maximum RAM consumption.
+    sed -i "s|#\?ConcurrentDatabaseReload.*|ConcurrentDatabaseReload no|g" /etc/clamav/clamd.conf; \
+# The default thread pool is 10-12 threads, each reserving its own stack and scan buffers.
+# The Nextcloud antivirus plugin sends one file at a time, so 2 threads are sufficient
+# and avoids the idle per-thread memory overhead of the larger default pool.
+    sed -i "s|#\?MaxThreads.*|MaxThreads 2|g" /etc/clamav/clamd.conf; \
     sed -i "s|#\?TCPSocket|TCPSocket|g" /etc/clamav/clamd.conf; \
     sed -i "s|^LocalSocket .*|LocalSocket /tmp/clamd.sock|g" /etc/clamav/clamd.conf; \
     sed -i "s|Example| |g" /etc/clamav/clamav-milter.conf; \

Containers/clamav/supervisord.conf

@@ -1,6 +1,5 @@
 [supervisord]
 nodaemon=true
-nodaemon=true
 logfile=/var/log/supervisord/supervisord.log
 pidfile=/var/run/supervisord/supervisord.pid
 childlogdir=/var/log/supervisord/