[Solved] How to optimize mysql table of 2 billions rows?

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How to optimize mysql table of 2 billions rows?

Database type:

We have a table for logging actions. The volume added up pretty fast. After about 3-4 months, we got 600M rows, we need to store the data for 1 year at least, so it is expected to host 2-3 billions rows.

The structure is not very complicated:

    CREATE TABLE `site_statistic` (
     `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
     `entityType` varchar(50) NOT NULL,
     `entityId` int(10) unsigned NOT NULL,
     `entityCount` int(10) unsigned NOT NULL DEFAULT '1',
     `timeStamp` int(10) unsigned NOT NULL,
     PRIMARY KEY (`id`),
     KEY `entity` (`entityType`,`timeStamp`,`entityId`)

Sample data:

Currently, data insert is not a problem (yet). But reading the data is very slow. It took 90+ seconds to query product activities for a given period of time:

            DATE_FORMAT(FROM_UNIXTIME(`timeStamp`), "%e") AS `category`,
            SUM(`entityCount`) as `count`
            `entityType` IN ('product.displayed','product.clicked','product.add')
            `timeStamp` >= 1527267600
            `timeStamp` <= 1527872399 AND entityId = 12807
        GROUP BY

Mysql crashed (or rather not responding) from time to time when many statistic reports are required at the same time.

Deleting the data (related to a product for example) is also very slow. We need to delete to save space...

What can we do to improve it, apart from disable real time report and send later by email?

P.s.: Our client can be considered small (few guys hosting a website with modest profit) not some crazy enterprise solution.

How to optimize this SQL query?

The following recommendations will help you in your SQL tuning process.
You'll find 3 sections below:

  1. Description of the steps you can take to speed up the query.
  2. The optimal indexes for this query, which you can copy and create in your database.
  3. An automatically re-written query you can copy and execute in your database.
The optimization process and recommendations:
  1. Create Optimal Indexes (modified query below): The recommended indexes are an integral part of this optimization effort and should be created before testing the execution duration of the optimized query.
  2. Explicitly ORDER BY After GROUP BY (modified query below): By default, the database sorts all 'GROUP BY col1, col2, ...' queries as if you specified 'ORDER BY col1, col2, ...' in the query as well. If a query includes a GROUP BY clause but you want to avoid the overhead of sorting the result, you can suppress sorting by specifying 'ORDER BY NULL'.
Optimal indexes for this query:
ALTER TABLE `site_statistic` ADD INDEX `site_statistic_idx_entityid_entitytype_timestamp` (`entityId`,`entityType`,`timeStamp`);
The optimized query:
        "%e") AS `category`,
        SUM(`site_statistic`.`entityCount`) AS `count` 
        `site_statistic`.`entityType` IN (
            'product.displayed', 'product.clicked', 'product.add'
        AND `site_statistic`.`timeStamp` >= 1527267600 
        AND `site_statistic`.`timeStamp` <= 1527872399 
        AND `site_statistic`.entityId = 12807 

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* original question posted on StackOverflow here.