I'm using postgreSQL 9.3 database and I have increased the
effective_cache_size in the settings.
Will postgreSQL always take this amount of memory or only when needed?
I'm running my database on an Amazon EC2 instance and I will monitor the memory with a CloudWatch custom metric and I'm now thinking about it if the memory I set in the configuration will always be reserved i.e. appears to be used in the cloudWatch metric.
If this is the case, how can I monitor the actual used memory of postgreSQL?