change the default to running maintenance only once every 4 hours

this leaves enough time for auto VACUUM (postsgresql) to do
its job when performing a lot of clean up on
low end systems (10 MB/s disk bandwidth)

docs/stellar-core_example.cfg

@@ -238,13 +238,13 @@ CATCHUP_RECENT=1024
 # This limits the number that will be active at a time.
 MAX_CONCURRENT_SUBPROCESSES=10
 
-# AUTOMATIC_MAINTENANCE_PERIOD (integer, seconds) default 3600
+# AUTOMATIC_MAINTENANCE_PERIOD (integer, seconds) default 14400
 # Interval between automatic maintenance executions
 # Set to 0 to disable automatic maintenance
-AUTOMATIC_MAINTENANCE_PERIOD=3600
+AUTOMATIC_MAINTENANCE_PERIOD=14400
 
 # AUTOMATIC_MAINTENANCE_COUNT (integer) default 50000
-# Number of unneeded rows in each table that will be removed during one
+# Number of unneeded ledgers in each table that will be removed during one
 # maintenance run.
 # Set to 0 to disable automatic maintenance
 AUTOMATIC_MAINTENANCE_COUNT=5000

src/main/Config.cpp

@@ -42,7 +42,7 @@ Config::Config() : NODE_SEED(SecretKey::random())
     MANUAL_CLOSE = false;
     CATCHUP_COMPLETE = false;
     CATCHUP_RECENT = 0;
-    AUTOMATIC_MAINTENANCE_PERIOD = std::chrono::seconds{3600};
+    AUTOMATIC_MAINTENANCE_PERIOD = std::chrono::seconds{14400};
     AUTOMATIC_MAINTENANCE_COUNT = 50000;
     ARTIFICIALLY_GENERATE_LOAD_FOR_TESTING = false;
     ARTIFICIALLY_ACCELERATE_TIME_FOR_TESTING = false;

src/main/Maintainer.cpp

@@ -17,9 +17,12 @@ Maintainer::Maintainer(Application& app) : mApp{app}, mTimer{mApp}
 void
 Maintainer::start()
 {
-    if (mApp.getConfig().AUTOMATIC_MAINTENANCE_PERIOD.count() > 0 &&
-        mApp.getConfig().AUTOMATIC_MAINTENANCE_COUNT > 0)
+    auto& c = mApp.getConfig();
+    if (c.AUTOMATIC_MAINTENANCE_PERIOD.count() > 0 &&
+        c.AUTOMATIC_MAINTENANCE_COUNT > 0)
+    {
         scheduleMaintenance();
+    }
 }
 
 void