Resource Pooling

OCK SCRLock

Introduction

This chapter describes how to install and use the SCRLock feature of the openGauss database. When resource pooling is enabled, SCRLock can be used to provide the distributed lock capability, improving distributed lock performance.

Preparations

Obtaining the Installation Package

Obtain the UWAL installation package from the openGauss community.

Environment Requirements

Table 1 Environment requirements

Table 2 Mapping between OS and OFED versions

Installation and Uninstallation

One-Click Deployment of the SCRLock Feature

SCRLock provides a simple deployment script. You can enter the installation path, installation user, and node information to perform one-click deployment.

• Prerequisites

  • RDMA is enabled. This function depends on the CX4/CX5 NIC.
  • openGauss has been deployed.
  • Obtain the SCRLock installation package corresponding to the OS and CPU architecture in use, for example, OCK_scrlock_openEuler-20.03-LTS-SP1-aarch64.tar.gz.
  • The ${GAUSSHOME}/lib directory exists on the active and standby nodes.
  • Users with the same user name and password are created for servers where SCRLock needs to be deployed. The users must have the permission to run the rmmod, rpm, depmod, and modprobe commands.

• Procedure

  1. Log in to the node as <SCRLock-install-user> and upload the installation package. Run the following command in the directory where the installation package is stored to decompress the installation package:

     tar -xzvf OCK_scrlock_openEuler-20.03-LTS-SP1-aarch64.tar.gz
     

     The following files are extracted.

     File	Description
     OCK_scrlock_openEuler_aarch64.tar.gz	Source package
     OCK_scrlock_openEuler_aarch64.tar.gz.txt	Signature file
     OCK_scrlock_openEuler_aarch64.tar.gz.cms	Description file

  2. Decompress the source package.

     tar -xzvf OCK_scrlock_openEuler_aarch64.tar.gz
     

     The following files are extracted.

     File	Description
     scrlock_lib	SO file
     scripts	Installation script
     umdk_rpm	RPM dependency package
     bin	Signature verification file

  3. Use the verification binary file in the bin directory to verify the software package signature.

     ./bin/verification OCK_scrlock_openEuler_aarch64.tar.gz OCK_scrlock_openEuler_aarch64.tar.gz.cms OCK_scrlock_openEuler_aarch64.tar.gz.txt
     

     NOTE: The verification binary file requires three parameters in sequence: source package, signature file, and description file.

     • If the verification is successful, the console displays the following information:

       Starting to verify OCK_scrlock_openEuler_aarch64.tar.gz...
       Verify the source file passed.
       Verify the sha file passed.
       

     • If the verification fails, the console displays the following information:

       Starting to verify OCK_scrlock_openEuler_aarch64.tar.gz...
       ...
       Verify the source file failed.
       

       Or

       Starting to verify OCK_scrlock_openEuler_aarch64.tar.gz...
       ...
       Verify the sha file failed.
       

       NOTE: If the verification fails, the installation package has been tampered with. You are advised to obtain the installation package again and verify it again.

  4. After the installation package is verified, go to the scripts directory.

     cd scripts
     

  5. Run the deployment script and enter the password of <SCRLock-install-user> as prompted.

     sh scrlock_install.sh -H '192.168.4.164 192.168.4.165 192.168.4.166' -U omm -G dbgrp -D /home/omm/lib
     

     NOTE:

     • -H: IP addresses in the cluster. Example: '192.168.4.164 192.168.4.165 192.168.4.166'
     • -U: user name of the database administrator. Example: omm
     • -G: user group of the database administrator. Example: dbgrp
     • -D: path to the ${GAUSSHOME}/lib library. Example: /home/omm/lib
     • -h: help information. Deployment through scripts requires a high-privilege user. After the operations are complete, disable the high-privilege user's permission to remotely log in to the server using SSH to improve system security.

  6. Switch to the database administrator.

     su - omm
     

  7. (Optional) Kill the om_monitor process.

     gs_om -t killmonitor
     

  8. Load environment variables.

     source ~/.bashrc
     

     NOTICE: Perform steps 6 to 8 on the standby node.

Enabling the SCRLock Feature

To enable the SCRLock feature, modify the configuration file and restart the database for the modification to take effect.

• Prerequisites

  • The openGauss version that contains the SCRLock feature has been installed on the active and standby nodes.
  • The SCRLock feature has been deployed in one-click mode.

• Procedure

  1. Log in to the management node as the database administrator.

  2. Modify the postgresql.conf file of the database.

     1. Open the postgresql.conf file.

        vim postgresql.conf
        

     2. Press i to enter the insert mode, find the following parameters, and modify them as required. Table 1 describes the parameters.

        ss_enable_scrlock = off
        ss_enable_srclock_sleep_mode = off
        ss_scrlock_server_port = 8000
        ss_scrlock_worker_count = 2
        ss_scrlock_worker_bind_core = ''
        ss_scrlock_server_bind_core = ''
        

        Table 1 SCRLock configuration parameters

        Parameter	Type	Description	Value Range	Default Value
        ss_enable_scrlock	Boolean	Specifies whether to enable SCRLock.	on: enable. off: disable.	off
        ss_enable_scrlock_sleep_mode	Boolean	Specifies whether to enable the SCRLock sleep mode.	on: enable. off: disable.	on
        ss_scrlock_server_port	Integer	Specifies the listening port number of the SCRLock server.	1024–65535	8000
        ss_scrlock_worker_count	Integer	Specifies the number of workers on the SCRLock client.	2–16	2
        ss_scrlock_worker_bind_core	Character string	Specifies the start and end CPU cores bound to SCRLock workers.	Format: "Start_CPU_core_index End_CPU_core_index". Separate the two indexes with a space. Example: 10 15	""
        ss_scrlock_server_bind_core	Character string	Specifies the start and end CPU cores bound to the SCRLock server.	Format: "Start_CPU_core_index End_CPU_core_index". Separate the two indexes with a space. Example: 10 15	""

     3. Press Esc, type :wq!, and press Enter to save the file and exit.

  3. Restart the database to enable the SCRLock feature.

     1. Stop openGauss.

        cm_ctl stop
        

     2. Start openGauss.

        cm_ctl start
        

        NOTE: If the startup fails, rectify the fault based on the postgresql-YYYY-MM-DD_HHMMSS.log file in the openGauss log directory.

  4. Verify that the SCRLock feature is successfully enabled.

     gsql -d postgres -p 16600 -c "show ss_enable_scrlock"
     

     If the following information is displayed, the feature is enabled successfully:

     ss_enable_scrlock
     -------------------
     on
     (1 row)
     

     NOTE:

     • -p 16600: 16600 indicates the database port number. Change it based on the actual environment.
     • To view SCRLock log files, run the following command to view the last 20 lines:

     tail -fn20 ${GAUSSLOG}/pg_log/scrlock*.log
     

Disabling the SCRLock Feature

To disable the SCRLock feature, modify the configuration file and restart the database for the configuration to take effect.

• Procedure

  1. Modify the postgresql.conf file in the root directory of the database.

     1. Open the postgresql.conf file.

        vim postgresql.conf
        

     2. Press i to enter the insert mode. Change the value of ss_enable_scrlock to off to disable the SCRLock feature.

        ss_enable_scrlock = off
        

     3. Press Esc, type :wq!, and press Enter to save the file and exit.

  2. Stop openGauss.

     cm_ctl stop
     

  3. (Optional) To uninstall the SCRLock feature, perform this step. Delete the SCRLock dynamic library file and clear the environment variable.

     rm -f /home/omm/lib/libscrlock.so
     unset OCK_SCRLOCK_LIB_PATH
     

     In the preceding commands, /home/omm/lib/ indicates the absolute path of the directory where libscrlock.so is located.

  4. Start openGauss.

     cm_ctl start