May 17, 2026, 11:40 PM

inbox/DataBase/PostgreSQL/dba_scripts/cache_hit_ratio.sh

@@ -0,0 +1,49 @@
+#!/bin/bash
+# Shows cache hit ratio for all databases
+
+USER=""
+PORT=""
+DBNAME="postgres"
+
+usage() {
+    echo "Usage: $0 [-d <dbname> -h <host> -U <user> -p <port>]"
+    exit 1
+}
+
+while getopts "d:h:p:uU:" OPT;
+do case "${OPT}" in
+      d) DBNAME=$OPTARG
+	 ;;
+      h) HOST="-h $OPTARG"
+	 ;;
+      p) PORT="-p $OPTARG"
+	 ;;
+      U) USER="-U $OPTARG"
+	 ;;
+      u) usage
+	 ;;
+    [?]) usage
+   esac;
+done
+
+if [ "$DBNAME" = "" ]
+  then
+    usage
+    exit 1
+fi
+
+psql $USER $HOST $PORT $DBNAME <<_EOF_
+SELECT pg_stat_database.datname,
+       pg_stat_database.blks_read,
+       pg_stat_database.blks_hit,
+       round((pg_stat_database.blks_hit::double precision
+	      / (pg_stat_database.blks_read
+		 + pg_stat_database.blks_hit
+		 +1)::double precision * 100::double precision)::numeric, 2) AS cachehitratio
+   FROM pg_stat_database
+  WHERE pg_stat_database.datname !~ '^(template(0|1)|postgres)$'::text
+  ORDER BY round((pg_stat_database.blks_hit::double precision
+		 / (pg_stat_database.blks_read
+		    + pg_stat_database.blks_hit
+		    + 1)::double precision * 100::double precision)::numeric, 2) DESC;
+_EOF_