Specify log compression

During log synchronization for a standby tenant, you can enable compression to reduce the bandwidth used for log transfer.

Procedure

1. Log in as the administrator to the standby tenant or the sys tenant of the cluster where the standby tenant resides.

2. Enable log compression.

   The tenant-level parameter log_transport_compress_all specifies whether to enable compression for log transfer. The default value is False, which specifies not to enable compression for log transfer. For more information about the log_transport_compress_all parameter, see log_transport_compress_all.

   The SQL syntax is as follows:

   ALTER SYSTEM SET log_transport_compress_all = value [TENANT [=] tenant_name];
   

   where:

   • SET is optional in MySQL mode.
   • value indicates the modified value of the parameter.
   • TENANT [=] tenant_name indicates the name of the tenant. You use this parameter to specify the name of the tenant only when you execute the statement in the sys tenant.

   Execute the following statement in the sys tenant to enable log compression for the specified standby tenant:

   obclient(root@sys)[(none)]> ALTER SYSTEM SET log_transport_compress_all = True TENANT = standby_tenant;
   

   Execute the following statement in a standby tenant to enable log compression for the standby tenant:

   MySQL mode

   Oracle mode

   The statement for enabling log compression for a MySQL tenant is as follows:

   obclient(root@standby_tenant)[(none)]> ALTER SYSTEM SET log_transport_compress_all = True;
   

   The statement for enabling log compression for an Oracle tenant is as follows:

   obclient(sys@standby_tenant)[SYS]> ALTER SYSTEM SET log_transport_compress_all = 'True';
   

   After you enable log compression, the system compresses logs based on the lz4_1.0 algorithm by default.

3. (Optional) Change the compression algorithm by modifying the log_transport_compress_func parameter.

   The tenant-level parameter log_transport_compress_func specifies the compression algorithm used for log transfer. Supported compression algorithms are lz4_1.0, zstd_1.0, and zstd_1.3.8. By default, the lz4_1.0 algorithm is used. For more information about the log_transport_compress_func parameter, see log_transport_compress_func.

   The SQL syntax is as follows:

   ALTER SYSTEM SET log_transport_compress_func = 'value' [TENANT [=] tenant_name];
   

   where:

   • SET is optional in MySQL mode.
   • value indicates the modified value of the parameter.
   • TENANT [=] tenant_name indicates the name of the tenant. You use this parameter to specify the name of the tenant only when you execute the statement in the sys tenant.

   Execute the following statement in the sys tenant to change the compression algorithm for the specified standby tenant:

   obclient(root@sys)[(none)]> ALTER SYSTEM SET log_transport_compress_func = 'zstd_1.0' TENANT = standby_tenant;
   

   Execute the following statement in a standby tenant to change the compression algorithm for the standby tenant:

   obclient> ALTER SYSTEM SET log_transport_compress_func = 'zstd_1.0';
   

References

• View cluster parameters

• Modify cluster parameters