I'm currently using Redis in my webProject (predis).
I'm using Redis as Cache server and when I get empty results from redis I would like to look into my MySQL database and store that result into redis.
Also, how would I dump the redis into MySQL to make sure MySQL has the up-to-date content? My plan is to dump redis into MySQL so if the redis is empty it will look in MySQL for the details.
How would I proceed to do this?
Should I do one or two?
After editing/inserting into Redis, do the same to MySQL
Redis -> dump to MySQL -> get from MySQL if empty.
I am assuming you mean to say these things as things are not clear from your question.
You are using Redis as Cache server and when you get empty results from redis you are going to look into your MySQL database and store that result into redis.
Well if your web application is in Java you can try few things as:
create a Jedis Connection.
try to get the value from redis corresponding to that key.
if nothing is returned. You can query the same from your database.
Set the (key value) to redis.
Related
I am trying to configure MySQL databases using the Master-Slave replication. Before I realized that I had to set up my environment using this replication, I already have 2 separate servers running their own MySQL DB. Each of these servers are configured the exact same. The MySQL DB are configured with hundreds of tables.
Is there a way that i can set up (Master-Slave) Replication using the configured DB's? Or will i have to start from scratch and configure the replication first and then load in all the DB tables?
You can delete all data from one of the servers. Remaining one with the data will be your Master. Then use mysqldump to backup all the data and insert it to the slave.
Take a look for the detailed instructions on the page below:
https://livecaller.io/blog/how-to-set-up-mysql-master-slave-replication/
If the data is exactly same in both the MySQL database then you can start master slave replication, but you need to be sure that the data is same. MySQL will not check that, and if there is some discrepancy in the primary key then it will throw error immediately after next DML statement.
To be on a safer side, drop the database from one server, and restore it using the MySQL dump of another server. This will give the surety that database is same on both the server.
Take the reference from the below link to establish replication between two MySQL servers.
https://www.digitalocean.com/community/tutorials/how-to-set-up-master-slave-replication-in-mysql
I'm trying to cluster a node app that runs with mysql, mysql session store and massive usage of socket.io.
I was looking for a way to adapt the socket.io session storage in mysql but i only found some redis adapter (following this guidelines : https://github.com/elad/node-cluster-socket.io)
Is there a way to implement node clustering with socket.io and mysql without installing redis ?
Have you tried using this module? https://www.npmjs.com/package/socket.io-mysql-session If it does not satisfy you, you will have to make your own socket.io session manager.This will not take more than 2-3 hours. I believe mysql is not exactly what you want to use to store socket.io data as a user is lost in every refresh meaning that a caching mechanism like redis is a better choice to use overall
I'm building a background service which boils down to a very complicated queue system. The idea is to use Redis as non-persistent storage, and have a sub/pub scheme which runs on an interval.
All of the subscribers will be behind a load balancer. This removes the complicated problem of maintaining state between all the servers behind the load balancer.
But, this introduces a new problem...how can I ensure that the non-persistent (Redis) and persistent (MySQL) databases are both updated by my application(s)?
It seems like I'm forced to prioritize one, and if I HAVE to prioritize one, I will prioritize persistence. But, in that scenario, what happens if MySQL is updated, Redis is not, and for some reason I have lost the connection to MySQL and cannot undo my last write?
There are two possible solutions to your problem:
Following these steps:
a. Start MySQL transaction with START TRANSACTION
b. Run your MySQL query INSERT INTO ...
c. Run your Redis command
d. Finish your MySQL transaction with COMMIT statement in case if Redis command succeeded or ROLLBACK if command failed
Using transctions ensures that data is consistent in both storages.
Write LUA script for Redis using LuaSQL library (https://realtimelogic.com/ba/doc/en/lua/luasql.html), where you will connect to MySQL, insert your data and then send commands to Redis as well. Then this LUA script can be called from client side with just one command EVAL or EVALSHA
You can try the mysql udf plugin (https://github.com/Ideonella-sakaiensis/lib_mysqludf_redis)
See the post: how to move data from mysql to redis
I'm trying to test the performance of using memcached on a MySQL server to improve performance.
I want to be able to use the normal MySQL command line, but I can't seem to get it to connect to memcached, even when I specify the right port.
I'm running the MySQL command on the same machine as both the memcached process and the MySQL server.
I've looked around online, but I can't seem to find anything about using memcached other than with program APIs. Any ideas?
Memcached has its own protocol. The MySQL client cannot connect directly to a memcached server.
You may be thinking of the MySQL 5.6 feature that allows MySQL server to respond to connections using a memcached-compatible protocol, and read and write directly to InnoDB tables. See http://dev.mysql.com/doc/refman/5.6/en/innodb-memcached.html
But this does not allow MySQL clients to connect to memcached -- it's the opposite, allowing memcached clients to connect to mysqld.
Re your comment:
The InnoDB memcached interface is not really a caching solution per se, it's a solution for using a familiar key/value API for persistent data in InnoDB tables. InnoDB does do transparent caching of data pages in its buffer pool, but this is no different from conventional data reads with SQL. InnoDB also commits all changes to its transaction log synchronously on commit.
Here's a blog from my colleague at Percona. He tested whether the MySQL 5.6 memcached API could be used as a caching layer, and found that actually using memcached is still superior.
http://www.mysqlperformanceblog.com/2013/03/29/mysql-5-6-innodb-memcached-plugin-as-a-caching-layer/
Here's one conclusion from that blog:
As expected, there is a slowdown for write operations when using the InnoDB version. But there is also a slight increase in the average fetch time.
I'm trying to implement a proxy layer in front of MySQL server, that will catch redundant SQL queries and send them only once to the server. In other words, I have many clients (in PHP, Perl, on different web nodes) that talk to the MySQL and very often repeat the same SELECT queries. When traffic goes up MySQL, very often, goes down.
The question is - are you aware of any open source (or commercial) tool that can help? I tried MySQL Proxy, but looks like it can't help.
Two suggestions:
MySQL Proxy
This is a front end proxy from MySQL which does what you want as far as I know
vtocc
From the vitess project, used in the YouTube mysql environment, also does a similar thing. Query consolidation: The ability to reuse the results of an in-flight query to any subsequent requests that were received while the query was still executing.
You may want to look into HAProxy and how it works.
Here two additional suggestions
SUGGESTION #1 Setup a Cluster
If your data is all InnoDB, you should try Percona XtraDB Cluster and use HAProxy in conjunction with it. You can load balance across all server in the Cluster including the Write Master.
SUGGESTION #2 Setup a Cluster via MySQL Replication to 1 or more DB Servers
Use HAProxy to load balance your reads across the Read Slaves
If you are on a budget and your data is relatively small, setup multiple MySQL Instances on one server