Update persistence.xml (#4004)

frameworks/Java/redkale/conf/persistence.xml

@@ -6,7 +6,7 @@
         <shared-cache-mode>ALL</shared-cache-mode>
         <properties>
             <property name="javax.persistence.jdbc.url" value="jdbc:postgresql://tfb-database:5432/hello_world"/>
-            <property name="javax.persistence.connections.limit" value="56"/>
+            <property name="javax.persistence.connections.limit" value="28"/>
             <property name="javax.persistence.datasource" value="org.redkalex.source.pgsql.PgSQLDataSource"/>
             <property name="javax.persistence.jdbc.user" value="benchmarkdbuser"/>
             <property name="javax.persistence.jdbc.password" value="benchmarkdbpass"/>