Collect MySQL query results - Log Service - Alibaba Cloud Documentation Center

This topic describes how to create a Logtail configuration in the Log Service console to collect MySQL query results.

Prerequisites

Logtail V0.16.0 or later is installed on a Linux server, or Logtail V1.0.0.8 or later is installed on a Windows server. For more information, see Install Logtail on a Linux server or Install Logtail on a Windows server.
Important Make sure that the server on which Logtail is installed can connect to the MySQL database from which you want to collect MySQL query results.
The IP address of the server on which Logtail is installed is added to a whitelist of the MySQL database from which you want to collect MySQL query results.
For more information about how to configure the whitelist, see Configure an IP address whitelist for an ApsaraDB RDS for MySQL instance.

Principle

Logtail executes the SELECT statement that is specified in a Logtail configuration on a regular basis, and then uploads the query results to Log Service.

After Logtail obtains query results, Logtail saves the value of the CheckPoint field in the results to the Logtail server. The next time Logtail executes the SELECT statement, Logtail adds the value of the CheckPoint field to the SELECT statement. This way, Logtail can collect incremental data.

Important If you use checkpoints during data collection, you must sort the values of the CheckPoint field in the SELECT statement. Otherwise, data duplication or other issues may occur.

Features

You can collect query results from MySQL databases.
You can configure paged query settings.
You can specify time zones.
You can specify timeout periods.
You can save the values of the CheckPoint field.
SSL is supported.
You can specify the maximum number of logs that can be collected at a time.

Scenarios

Collect incremental data based on marks such as an auto-increment ID or a point in time.
Synchronize data based on filter conditions.

Procedure

Log on to the Log Service console.
In the Import Data section, find and click MySQL Query Result - Plug-in.
Select the project and Logstore. Then, click Next.
Create a machine group.
- If a machine group is available, click Use Existing Machine Groups.
- If no machine groups are available, perform the following steps to create a machine group. In this example, an Elastic Compute Service (ECS) instance is used.
  1. On the ECS Instances tab, select Manually Select Instances. Then, select the ECS instance that you want to use and click Create.
    For more information, see Install Logtail on ECS instances.
    Important If you want to collect logs from an ECS instance that belongs to a different Alibaba Cloud account, a server in an on-premises data center, or a server of a third-party cloud service provider, you must manually install Logtail. For more information, see Install Logtail on a Linux server or Install Logtail on a Windows server. After you manually install Logtail, you must configure a user identifier for the server. For more information, see Configure a user identifier.
  2. After Logtail is installed, click Complete Installation.
  3. In the Create Machine Group step, configure the Name parameter and click Next.
    Log Service allows you to create IP address-based machine groups and custom identifier-based machine groups. For more information, see Create an IP address-based machine group and Create a custom identifier-based machine group.
Select the new machine group from Source Server Groups and move the machine group to Applied Server Groups. Then, click Next.
Important If you apply a machine group immediately after you create the machine group, the heartbeat status of the machine group may be FAIL. This issue occurs because the machine group is not connected to Log Service. To resolve this issue, you can click Automatic Retry. If the issue persists, see What do I do if no heartbeat connections are detected on Logtail?
In the Specify Data Source step, configure the Config Name and Plug-in Configuration parameters. Then, click Next.
You can specify a data source by using form configuration or editor configuration in JSON. For more information, see Details of the Logtail configuration.
Preview data, configure indexes, and then click Next.
By default, full-text indexing is enabled for Log Service. You can also configure field indexes based on collected logs in manual mode or automatic mode. To configure field indexes in automatic mode, click Automatic Index Generation. This way, Log Service automatically creates field indexes. For more information, see Create indexes.
Important If you want to query and analyze logs, you must enable full-text indexing or field indexing. If you enable both full-text indexing and field indexing, the system uses only field indexes.
Click Log Query. You are redirected to the query and analysis page of your Logstore.
You must wait approximately 1 minute for the indexes to take effect. Then, you can view the collected logs on the Raw Logs tab. For more information, see Query and analyze logs.

Details of the Logtail configuration

You can specify a data source by using form configuration or editor configuration in JSON.

Form configuration

In the Specify Data Source step, configure the following parameters.


Parameter	Description
Config Name	The name of the Logtail configuration.
MySQLAddress	The address of the MySQL database. Example: `rm-****.mysql.rds.aliyuncs.com`.
Database Username	The username of the account that is used to log on to the MySQL database.
Database Password	The password of the account that is used to log on to the MySQL database. If you have high requirements for data security, we recommend that you set the username and password to `xxx`. After your configurations are synchronized to the Logtail server, find the two parameters in the /usr/local/ilogtail/user_log_config.json file and change the values based on your business requirements. For more information, see Modify the Logtail configuration on the Logtail server. Important If you modify this parameter in the Log Service console, the parameter setting in the Logtail configuration on the Logtail server is overwritten after the modification is synchronized to the server.
Database Name	The name of the MySQL database.
Database Connection Timeout Period	The timeout period for connections to the MySQL database. Unit: milliseconds.
Query Timeout Period	The timeout period for reads from the MySQL database. Unit: milliseconds.
SELECT Statement	The SELECT statement. If you select Use CheckPoint, you must include the column that is specified for the CheckPoint Column Name parameter in a WHERE clause of the SELECT statement that you specify for the SELECT Statement parameter. You can use question marks (?) to indicate replacement characters. If you use a question mark in the SELECT statement, you must also configure the CheckPoint Column Name parameter. For example, if you set the CheckPoint Column Name parameter to id and set the Initial Value of CheckPoint Column parameter to 0, you must specify the value of the SELECT Statement parameter in the `SELECT * from ... where id > ?` format. Each time a query is performed, the system saves the ID of the last data record as the checkpoint. In the next query, the question mark (?) that is specified in the SELECT statement is replaced with the ID that corresponds to the saved checkpoint.
Use LIMIT Clause to Perform Paged Queries	Specifies whether to use a LIMIT clause to paginate query results. We recommend that you select Use LIMIT Clause to Perform Paged Queries. If you select Use LIMIT Clause to Perform Paged Queries, a LIMIT clause is automatically added to the SELECT statement that you specify for the SELECT Statement parameter when Logtail executes the SQL statement.
Page Size	The maximum number of logs that can be returned on each page. If you select Use LIMIT Clause to Perform Paged Queries, you must configure this parameter.
Maximum Records per Synchronization	The maximum number of logs that can be synchronized at a time. Default value: 0, which indicates that the number is unlimited.
Use CheckPoint	Specifies whether to use checkpoints during data collection. If you select Use CheckPoint, checkpoints are used during data collection. A checkpoint can be used as the start point of the next data collection. This way, incremental data is collected.
CheckPoint Column Name	The name of the column that stores checkpoints. If you select Use CheckPoint, you must configure this parameter. Warning Values in the checkpoint column must be incremental. Otherwise, some data may not be collected. The maximum value in the results of a query operation is used as the input for the next query operation.
Data Type of CheckPoint Column	The type of the checkpoint column. Valid values: int and time. If you set this parameter to int, the values in the checkpoint column are of the int64 type. If you set this parameter to time, the values in the checkpoint column can be of the date, datetime, or time type that is supported by MySQL. If you select Use CheckPoint, you must configure this parameter.
Initial Value of CheckPoint Column	The initial value of the checkpoint column. If you select Use CheckPoint, you must configure this parameter.
Save CheckPoint per Pagination	If you select Save CheckPoint per Pagination, checkpoints are saved each time query results are paginated. If you do not select Save CheckPoint per Pagination, checkpoints are saved each time query results are synchronized.
Synchronized At	The synchronization interval. Unit: milliseconds.

Editor configuration in JSON

In the Plug-in Configuration field, specify information about your Logtail configuration.

inputs is required and is used to configure the data source settings for the Logtail configuration.
Important You can specify only one type of data source in inputs.
processors is optional and is used to configure the data processing settings for the Logtail configuration to parse data. For example, you can extract fields, extract log time, mask data, and filter logs. You can specify one or more processing methods. For more information, see Overview.

{
  "inputs": [
    {
      "type": "service_mysql",
      "detail": {
        "Address": "************.mysql.rds.aliyuncs.com",
        "User": "****",
        "Password": "*******",
        "DataBase": "****",
        "Limit": true,
        "PageSize": 100,
        "StateMent": "select * from db.VersionOs where time > ?",
        "CheckPoint": true,
        "CheckPointColumn": "time",
        "CheckPointStart": "2018-01-01 00:00:00",
        "CheckPointSavePerPage": true,
        "CheckPointColumnType": "time",
        "IntervalMs": 60000
      }
    }
  ]
}


Parameter	Type	Required	Description
type	string	No	The type of the data source. Set the value to service_mysql.
Address	string	No	The address of the MySQL database. Example: `rm-****.mysql.rds.aliyuncs.com`. Default value: 127.0.0.1:3306.
User	string	No	The username of the account that is used to log on to the MySQL database. Default value: root.
Password	string	No	The password of the account that is used to log on to the MySQL database. This parameter is empty by default. If you have high requirements for data security, we recommend that you set the username and password to `xxx`. After your configurations are synchronized to the Logtail server, find the two parameters in the /usr/local/ilogtail/user_log_config.json file and change the values based on your business requirements. For more information, see Modify the Logtail configuration on the Logtail server. Important If you modify this parameter in the Log Service console, the parameter setting in the Logtail configuration on the Logtail server is overwritten after the modification is synchronized to the server.
DataBase	string	No	The name of the MySQL database.
DialTimeOutMs	int	No	The timeout period for connections to the MySQL database. Unit: milliseconds. Default value: 5000.
ReadTimeOutMs	int	No	The timeout period for reads from the MySQL database. Unit: milliseconds. Default value: 5000.
StateMent	string	No	The SELECT statement. If you set the CheckPoint parameter to true, you must include the column that is specified for the CheckPointColumn parameter in a WHERE clause of the SELECT statement that you specify for the StateMent parameter. You can use question marks (?) to indicate replacement characters. If you use a question mark in the SELECT statement, you must also configure the CheckPointColumn parameter. For example, if you set the CheckPointColumn parameter to id and set the CheckPointStart parameter to 0, you must specify the value of the StateMent parameter in the `SELECT * from ... where id > ?` format. Each time a query is performed, the system saves the ID of the last data record as the checkpoint. In the next query, the question mark (?) that is specified in the SELECT statement is replaced with the ID that corresponds to the saved checkpoint.
Limit	boolean	No	Specifies whether to use a LIMIT clause to paginate query results. Valid values: true false (default) We recommend that you set the Limit parameter to true. If you set the Limit parameter to true, a LIMIT clause is automatically added to the SELECT statement that you specify for the StateMent parameter when Logtail executes the SQL statement.
PageSize	int	No	The maximum number of logs that can be returned on each page. If you set the Limit parameter to true, you must configure this parameter.
MaxSyncSize	int	No	The maximum number of logs that can be synchronized at a time. Default value: 0, which indicates that the number is unlimited.
CheckPoint	boolean	No	Specifies whether to use checkpoints during data collection. Valid values: true false (default) A checkpoint can be used as the start point of the next data collection. This way, incremental data is collected.
CheckPointColumn	string	No	The name of the column that stores checkpoints. If you set the CheckPoint parameter to true, you must configure this parameter. Warning Values in the checkpoint column must be incremental. Otherwise, some data may not be collected. The maximum value in the results of a query operation is used as the input for the next query operation.
CheckPointColumnType	string	No	The type of the checkpoint column. Valid values: int and time. If you set this parameter to int, the values in the checkpoint column are of the int64 type. If you set this parameter to time, the values in the checkpoint column can be of the date, datetime, or time type that is supported by MySQL. If you set the CheckPoint parameter to true, you must configure this parameter.
CheckPointStart	string	No	The initial value of the checkpoint column. If you set the CheckPoint parameter to true, you must configure this parameter.
CheckPointSavePerPage	boolean	No	Specifies whether to save checkpoints each time query results are paginated. Valid values: true (default): saves checkpoints each time query results are paginated. false: saves checkpoints each time query results are synchronized.
IntervalMs	int	Yes	The synchronization interval. Unit: milliseconds. Default value: 60000.

Modify the Logtail configuration on the Logtail server

If you did not enter real information for parameters such as Address, User, and Password in Plug-in Config when you created the Logtail configuration, you can modify the parameters after the Logtail configuration is delivered to the Logtail server.

Log on to the Logtail server.
Find the service_mysql keyword in the /usr/local/ilogtail/user_log_config.json file and modify parameters such as Address, User, and Password.

Run the following command to restart Logtail:

sudo /etc/init.d/ilogtaild stop; sudo /etc/init.d/ilogtaild start

Troubleshooting

If no data is displayed on the preview page or query page after logs are collected by using Logtail, you can troubleshoot the errors based on the instructions that are provided in What do I do if errors occur when I use Logtail to collect logs?

Sample database table and sample log

This section provides a sample database table and a sample log that is collected by Logtail.

Sample database table

CREATE TABLE `VersionOs` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT COMMENT 'id',
  `time` datetime NOT NULL,
  `version` varchar(10) NOT NULL DEFAULT '',
  `os` varchar(10) NOT NULL,
  `count` int(11) unsigned NOT NULL,
  PRIMARY KEY (`id`),
  KEY `timeindex` (`time`)
)

Sample log

"count":  "4"  
"id:  "721097"  
"os:  "Windows"  
"time:  "2022-08-25 13:00:00"  
"version":  "1.3.0"