Resizing online redo logs - Amazon Relational Database Service

Resizing online redo logs

An Amazon RDS DB instance running Oracle starts with four online redo logs, 128 MB each. The following example shows how you can use Amazon RDS procedures to resize your logs from 128 MB each to 512 MB each. 

/* Query V$LOG to see the logs.          */
/* You start with 4 logs of 128 MB each. */

SELECT GROUP#, BYTES, STATUS FROM V$LOG;

GROUP#     BYTES      STATUS
---------- ---------- ----------------
1          134217728  INACTIVE
2          134217728  CURRENT
3          134217728  INACTIVE
4          134217728  INACTIVE


/* Add four new logs that are each 512 MB */

EXEC rdsadmin.rdsadmin_util.add_logfile(bytes => 536870912);
EXEC rdsadmin.rdsadmin_util.add_logfile(bytes => 536870912);
EXEC rdsadmin.rdsadmin_util.add_logfile(bytes => 536870912);
EXEC rdsadmin.rdsadmin_util.add_logfile(bytes => 536870912);


/* Query V$LOG to see the logs. */ 
/* Now there are 8 logs.        */

SELECT GROUP#, BYTES, STATUS FROM V$LOG;

GROUP#     BYTES      STATUS
---------- ---------- ----------------
1          134217728  INACTIVE
2          134217728  CURRENT
3          134217728  INACTIVE
4          134217728  INACTIVE
5          536870912  UNUSED
6          536870912  UNUSED
7          536870912  UNUSED
8          536870912  UNUSED


/* Drop each inactive log using the group number. */

EXEC rdsadmin.rdsadmin_util.drop_logfile(grp => 1);
EXEC rdsadmin.rdsadmin_util.drop_logfile(grp => 3);
EXEC rdsadmin.rdsadmin_util.drop_logfile(grp => 4);


/* Query V$LOG to see the logs. */ 
/* Now there are 5 logs.        */

select GROUP#, BYTES, STATUS from V$LOG;

GROUP#     BYTES      STATUS
---------- ---------- ----------------
2          134217728  CURRENT
5          536870912  UNUSED
6          536870912  UNUSED
7          536870912  UNUSED
8          536870912  UNUSED


/* Switch logs so that group 2 is no longer current. */

EXEC rdsadmin.rdsadmin_util.switch_logfile;


/* Query V$LOG to see the logs.        */ 
/* Now one of the new logs is current. */

SQL>SELECT GROUP#, BYTES, STATUS FROM V$LOG;

GROUP#     BYTES      STATUS
---------- ---------- ----------------
2          134217728  ACTIVE
5          536870912  CURRENT
6          536870912  UNUSED
7          536870912  UNUSED
8          536870912  UNUSED


/* If the status of log 2 is still "ACTIVE", issue a checkpoint to clear it to "INACTIVE".  */

EXEC rdsadmin.rdsadmin_util.checkpoint;


/* Query V$LOG to see the logs.            */ 
/* Now the final original log is inactive. */

select GROUP#, BYTES, STATUS from V$LOG;

GROUP#     BYTES      STATUS
---------- ---------- ----------------
2          134217728  INACTIVE
5          536870912  CURRENT
6          536870912  UNUSED
7          536870912  UNUSED
8          536870912  UNUSED


# Drop the final inactive log.

EXEC rdsadmin.rdsadmin_util.drop_logfile(grp => 2);


/* Query V$LOG to see the logs.    */ 
/* Now there are four 512 MB logs. */

SELECT GROUP#, BYTES, STATUS FROM V$LOG;

GROUP#     BYTES      STATUS
---------- ---------- ----------------
5          536870912  CURRENT
6          536870912  UNUSED
7          536870912  UNUSED
8          536870912  UNUSED