Maintenance Plans - SQL Server to Aurora PostgreSQL Migration Playbook
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Maintenance Plans

Feature compatibility Amazon SCT / Amazon DMS automation level Amazon SCT action code index Key differences


                              Three star feature compatibility

N/A

N/A

Backups using the Amazon RDS services. Table maintenance using SQL commands.

SQL Server Usage

A maintenance plan is a set of automated tasks used to optimize a database, performs regular backups, and ensure it is free of inconsistencies. Maintenance plans are implemented as SQL Server Integration Services (SSIS) packages and are run by SQL Server Agent jobs. You can run them manually or automatically at scheduled time intervals.

SQL Server provides a variety of pre-configured maintenance tasks. You can create custom tasks using TSQL scripts or operating system batch files.

Maintenance plans are typically used for the following tasks:

  • Backing up database and transaction log files.

  • Performing cleanup of database backup files in accordance with retention policies.

  • Performing database consistency checks.

  • Rebuilding or reorganizing indexes.

  • Decreasing data file size by removing empty pages (shrink a database).

  • Updating statistics to help the query optimizer obtain updated data distributions.

  • Running SQL Server Agent jobs for custom actions.

  • Running a T-SQL task.

Maintenance plans can include tasks for operator notifications and history or maintenance cleanup. They can also generate reports and output the contents to a text file or the maintenance plan tables in the msdb database.

You can create and manage maintenance plans using the maintenance plan wizard in SQL Server Management Studio, Maintenance Plan Design Surface (provides enhanced functionality over the wizard), Management Studio Object Explorer, and T-SQL system stored procedures.

For more information, see SQL Server Agent and PostgreSQL Scheduled Lambda.

Deprecated DBCC Index and Table Maintenance Commands

The DBCC DBREINDEX, INDEXDEFRAG, and SHOWCONTIG commands have been deprecated as of SQL Server 2008R2. For more information, see Deprecated Database Engine Features in SQL Server 2008 R2 in the SQL Server documentation.

In place of the deprecated DBCC, SQL Server provides newer syntax alternatives as detailed in the following table.

Deprecated DBCC command Use instead

DBCC DBREINDEX

ALTER INDEX …​ REBUILD

DBCC INDEXDEFRAG

ALTER INDEX …​ REORGANIZE

DBCC SHOWCONTIG

sys.dm_db_index_physical_stats

For the Amazon Aurora PostgreSQL-Compatible Edition (Aurora PostgreSQL) alternatives to these maintenance commands, see Aurora PostgreSQL Maintenance Plans.

Examples

Enable Agent XPs, which are disabled by default.

EXEC [sys].[sp_configure] @configname = 'show advanced options', @configvalue = 1 RECONFIGURE ;
EXEC [sys].[sp_configure] @configname = 'agent xps', @configvalue = 1 RECONFIGURE;

Create a T-SQL maintenance plan for a single index rebuild.

USE msdb;

Add the Index Maintenance IDX1 job to SQL Server Agent.

EXEC dbo.sp_add_job @job_name = N'Index Maintenance IDX1', @enabled = 1, @description = N'Optimize IDX1 for INSERT' ;

Add the T-SQL job step Rebuild IDX1 to 50 percent fill.

EXEC dbo.sp_add_jobstep @job_name = N'Index Maintenance IDX1', @step_name = N'Rebuild IDX1 to 50 percent fill', @subsystem = N'TSQL',
@command = N'Use MyDatabase; ALTER INDEX IDX1 ON Shcema.Table REBUILD WITH ( FILL_FACTOR = 50), @retry_attempts = 5, @retry_interval = 5;

Add a schedule to run every day at 01:00 AM.

EXEC dbo.sp_add_schedule @schedule_name = N'Daily0100', @freq_type = 4, @freq_interval = 1, @active_start_time = 010000;

Associate the schedule Daily0100 with the job index maintenance IDX1.

EXEC sp_attach_schedule @job_name = N'Index Maintenance IDX1' @schedule_name = N'Daily0100' ;

For more information, see Maintenance Plans in the SQL Server documentation.

PostgreSQL Usage

Amazon Relational Database Service (Amazon RDS) performs automated database backups by creating storage volume snapshots that back up entire instances, not individual databases.

Amazon RDS creates snapshots during the backup window for individual database instances and retains snapshots in accordance with the backup retention period. You can use the snapshots to restore a database to any point in time within the backup retention period.

Note

The state of a database instance must be ACTIVE for automated backups to occur.

You can backup database instances manually by creating an explicit database snapshot. Use the Amazon console, the Amazon CLI, or the Amazon API to take manual snapshots.

Examples

Create a manual database snapshot using the Amazon RDS console

  1. In the Amazon console, choose RDS, and then choose Databases.

  2. Choose your Aurora PostgreSQL instance, and for Instance actions choose Take snapshot.

    
                           Take snapshot

Restore a snapshot using the Amazon RDS console

  1. In the Amazon console, choose RDS, and then choose Snapshots.

  2. Choose the snapshot to restore, and for Actions choose Restore snapshot.

    This action creates a new instance.

  3. Enter the required configuration options in the wizard for creating a new Amazon Aurora database instance. Choose Restore DB Instance.

You can also restore a database instance to a point-in-time. For more information, see Backup and Restore.

For all other tasks, use a third-party or a custom application scheduler.

Rebuild and reorganize a table

Aurora PostgreSQL supports the VACUUM, ANALYZE, and REINDEX commands, which are similar to the REORGANIZE option of SQL Server indexes.

VACUUM MyTable;
ANALYZE MyTable;
REINDEX TABLE MyTable;
  • VACUUM reclaims storage.

  • ANALYZE collects statistics.

  • REINDEX recreates all indexes.

For more information, see ANALYZE, VACUUM, and REINDEX in the PostgreSQL documentation.

Convert deprecated DBCC index and table maintenance commands

Deprecated DBCC command Aurora PostgreSQL equivalent

DBCC DBREINDEX

REINDEX INDEX or REINDEX TABLE

DBCC INDEXDEFRAG

VACUUM table_name or VACUUM table_name column_name

Update statistics to help the query optimizer get updated data distribution

For more information, see SQL Server Managing Statistics and PostgreSQL Table Statistics.

Summary

The following table summarizes the key tasks that use SQL Server maintenance plans and a comparable Aurora PostgreSQL solutions.

Task SQL Server Aurora PostgreSQL

Rebuild or reorganize indexes

ALTER INDEX or ALTER TABLE

REINDEX INDEX or REINDEX TABLE

Decrease data file size by removing empty pages

DBCC SHRINKDATABASE or DBCC SHRINKFILE

VACUUM

Update statistics to help the query optimizer get updated data distribution

UPDATE STATISTICS or sp_updatestats

ANALYZE

Perform database consistency checks

DBCC CHECKDB or DBCC CHECKTABLE

N/A

Back up the database and transaction log files

BACKUP DATABASE or BACKUP LOG

Automatically (for example, using Amazon CLI)

Run SQL Server Agent jobs for custom actions

sp_start_job or scheduled

N/A

For more information, see Working with backups in the PostgreSQL documentation.