We are seeing high apply lag on standby. The # of redo and size of redo matches the standby redo log file. We are using Real time apply. standby is waiting for the following sequence for almost 16 min. Does it mean because the log switch is not happening we are seeing lag?
Primary alert log
Tue Mar 24 10:04:09 2015
Thread 2 advanced to log sequence 146538 (LGWR switch)
Current log# 8 seq# 146538 mem# 0: +REDO1/orclprd/onlinelog/orclprd_redo_thr2_grp8a.rdo
Current log# 8 seq# 146538 mem# 1: +REDO2/orclprd/onlinelog/orclprd_redo_thr2_grp8b.rdo
Tue Mar 24 10:13:56 2015
Archived Log entry 287089 added for thread 2 sequence 146538 ID 0xb99dd31c dest 1:
Tue Mar 24 10:13:57 2015
ARC0: Standby redo logfile selected for thread 2 sequence 146538 for destination LOG_ARCHIVE_DEST_2
Standy alert log
Tue Mar 24 10:19:37 2015
Media Recovery Waiting for thread 2 sequence 146538 (in transit)
Recovery of Online Redo Log: Thread 2 Group 53 Seq 146538 Reading mem 0
Mem# 0: +REDO1/orclprd/onlinelog/orclprd_stdby_thr2_grp53a.rdo
Mem# 1: +REDO1/orclprd/onlinelog/orclprd_stdby_thr2_grp53b.rdo
PROCESS STATUS THREAD# SEQUENCE# BLOCK# BLOCKS
--------- ------------ ---------- ---------- ---------- ----------
MRP0 APPLYING_LOG 2 146538 1 2048000