Question

I am using a mysql database. The query is executed directly via the workbench tool.
The query looks like following:

SELECT records.received, data.value 
FROM product 
       JOIN records 
            on product.productId= records.productId 
       JOIN data 
            ON records.recordId = data.recordId 
       JOIN dataTypes 
            ON data.typeId = dataTypes.typeId 
ORDER BY records.received DESC

The data table has 1million entries.
The execution of this statement lasts 7 seconds. The reason seems to be the ORDER BY clause.

Can someone give me a hint how to speed it up.

Edit: sorry I forgot to add the structure:

products: PK is productId (it has only 5 entries)

records: PK is recordId and FK is productId

data: PK is dataId and FK recordId and typeId

dataTypes: PK is typeId

There is an Index on records.received and on all PK and FK.

Here is the output of EXPLAIN:

id,select_type,table,type,possible_keys,key,key_len,ref,rows,Extra
1,SIMPLE,products,const,PRIMARY,PRIMARY,4,const,1,"Using index
1,SIMPLE,dataTypes,const,PRIMARY,PRIMARY,4,const,1,"Using index"
1,SIMPLE,records,ref,"PRIMARY,productId",productId,4,const,127142,"Using where"
1,SIMPLE,data,ref,"recordId,typeId",recordId,4,top70.records.recordId,1,"Using where"

Answer 1

ALTER TABLE `records` ADD INDEX `index1` (`received`);
ALTER TABLE `data` ADD INDEX `index2` (`value `);

try to index your coloumns on which you are using where clause or selecting the coloumns