krisiye

-- Cache hit ratio.
-- Sweet spot here are values close to 100 which also means all necessary data were read from shared buffers. 
-- values near 90 or lower show that postgres read from disk time to time.
SELECT
    round(100 * sum(blks_hit) / sum(blks_hit + blks_read), 3) as cache_hit_ratio
FROM pg_stat_database;

-- estimate commit ratio and detect errors
-- values that are closer to 100 mean that you database has very few errors. 
SELECT

krisiye

-- tested with postgres13. Lower versions may need tweaks.

-- Top 20 cpu heavy queries
SELECT
    query AS short_query, 
    round((total_plan_time + total_exec_time)::numeric, 2),
    calls,
    rows,
    round((total_plan_time + total_exec_time)::numeric / calls, 2) AS avg_time,
    round((100 * (total_plan_time + total_exec_time) / sum((total_plan_time + total_exec_time)::numeric) OVER ())::numeric, 2) AS percentage_cpu

krisiye

-- Temporary file usage by database
SELECT datname AS "database", temp_files AS "Temporary files", temp_bytes 
AS "Size of temporary files" 
FROM pg_stat_database;

-- Cache Hit Ratio. Anything greater than 90% is always good
SELECT sum(blks_hit)*100/sum(blks_hit+blks_read) AS hit_ratio FROM pg_stat_database;

-- Top Queries
SELECT substr(query, 0, 250), calls, 

krisiye

package example.springboot.config;

import javax.annotation.PostConstruct;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;

krisiye

package example.springboot.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import com.amazonaws.auth.AWSCredentials;

krisiye

package example.springboot.config;

import static example.springboot.config.AwsConfigurationProperties.PREFIX;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

/**
 * Sample ConfigurationProperties for AWS STS
 * 

krisiye

// example with a hashmap to demonstrate how we could end up missing hashmap entries
// under concurrent modification.

package test;

import java.util.HashMap;

public class MapTestTask implements Runnable {

    private static HashMap<Object, Object> hashMap;