I have big db of size 8GB and having 9 million contacts in this db. When we try to retrieve all contacts, it takes nearly 1 or 2 hour (in some cases result in timeout) to retreive all contacts for the excecution for a single query. Also I have 8 CPU and 24GB RAM, Xeon Processor, the mysql process won't distribute accross the 8 CPU's. My question is that, does we can enable multi threading for a single query.

Awaiting for your Reply

Sounds more like a badly designed query, think about index optimisation etc. first. It's my belief (may be wrong!) that MySQL doesn't thread single queries.

What do you mean by "When we try to retrieve all contacts"? Retrieve them all to what - web browser, file, etc? Very often the data path can be the cause of slow retreival for very large result sets.

And I agree with TenTenths, you should probably look at your query itself, indexing, sorts on large result sets. You do not say what GNU/Linux or MySQL version, but in general it is pretty good about making good use of resources.

So, I would first look at bottlenecks in the retreival path and the query.

I'm trying to retreive all contacts to web browser and it have the function indexing for all query, MYsql version 5.56

I still have no idea what you are asking.

At first I thought that you were talking about retreiving ALL 9 million records at once. If so, and if you are retreiving them into a browser... then good luck! Not only would that take forever, it would also be mostly useless.

But I suspect that you are asking about retreiving some subset of records such as all contacts in a certain location, or with a certain name, etc. If that is the case then it will depend on the schema (table structure), indexing and how the queries are structured.

So, could you provide at least the following:

1. The table structure you are querying
2. An example of a query you are using to return some subset of records

Then we cna begin to offer useful suggestions.