[Postgres-xc-general] Our general use case

[David H. <pg...@c0...>]

 

Hi, 

I've been reading the 'ERROR: FAILED TO GET POOLED
CONNECTIONS' thread about what XC should and should not do. I opted to
start a new thread (instead of replying) about how I would like XC to
be. 

Some background. I work for a SaaS company (mostly dev, some ops)
which has to be online 24/7. We are now running apache/tomcat/mysql for
each set of customers on about 30 nodes and we want to centralize and
make our application more robust, efficient and simple. It basically
means creating layers: LB, webservers, application servers, database
cluster. Some easy parts are already done (haproxy, nginx). Our
'platform' is pretty complex and I have so many tasks, I prefer to _not_
dig into details. We are now discussing the db issue (mysql cluster is
not that great). 

My dream DB cluster: 

Scalability - that means read
and write scalability. XC should do that right now. Nice. 

High
availability - a node can go offline and it should not hinder
availability (only processing capacity) 

Maintainability - Since
maintenance/change is our primary cause of downtime, it should be
possible to kill a node and add it later. This can be because the VM is
being moved, the OS is updated/upgraded, etc. Also, think about how a
cluster is updated from major version to major version (lets say 9.x to
10.x). Maybe that is not an issue (but I don't know about it yet).


Simplicity - It would be nice if the default package+config file is
all I need. If it is too complex I cannot go on holidays. Some points:


 	* I read that _'...even the stock postgresql.conf configuration file
is pretty conservative and users tweak it as per their
requirements..._'. For me that translates as 'if you are new to Postgres
it works bad'. Not simple (for e.g. some of our dev-ers).
 	* For HA_
'...Like Postgres, you need an external application to provide it'_.
When using a cluster I think HA is very often wanted. I need to explain
all this to every ops-colleague of mine and some are not very accurate.
Not simple again. 

Quick setup - I want to setup an NxM cluster quickly
(N times duplication for HA, M times distributed writes for
performance). I prefer to setup a single node with a given config file,
add nodes and be ready to go. Maybe an hour in case of disaster
recovery? 

Managability - I want to manage a cluster easily (add node,
remove node, spare nodes, monitoring, ...). It cannot be simple enough.


Backup - I'm not familiar with running backups on Postgres but we
currently run a blocking backup on the mysql, for consistency, and it
causes issues. We use Bacula on a file level. Which brings up a
question: How do you backup a cluster (if you don't know which nodes are
hot)? 

Logging - Yes... 

Some may respond that things are not that
simple. I know. But I still want it to be simple. It would make PGXC a
no-brainer for everyone. Thanks for listening and keep up the good work!
I appreciate it. 

David H.