H2O: Adjust the number of database connections (#3447)

This is the first step to tune the number of database connections,
especially for the Citrine environment.

frameworks/C/h2o/start-servers.sh

@@ -14,10 +14,10 @@ if [[ "$CPU_COUNT" -gt 16 ]]; then
 	# In the physical hardware environment the number of threads used by the application is not
 	# the same as the number of logical CPU cores that the database server has, so we need to
 	# adjust the maximum number of database connections per thread accordingly.
-	DB_CONN=1
+	DB_CONN=2
 else
 	USE_PROCESSES=false
-	DB_CONN=16
+	DB_CONN=8
 fi
 
 build_h2o_app()
@@ -80,4 +80,4 @@ else
 	run_h2o_app 0 "${H2O_APP_HOME}/bin" "${H2O_APP_HOME}/share/h2o_app"
 fi
 
-wait
+wait