Is one of these applying from lgwr and the other by shipping logs? (Sorry no
time to read the details.) That would explain both the lag and the faster
maximum apply rate, because after the log switches and finally is shipped it
applies very quickly locally with zero network ack/nak of success application.
Before it was possibly to write to the standby from lgwr, that was the way it
worked for all the standbys.
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On ;
Behalf Of John Thomas
Sent: Friday, January 04, 2019 12:27 PM
To: Sandra Becker
Cc: Neil Chandler; Andrew Kerber; oracle-l
Subject: Re: One primary with two physical standbys exhibiting different
behavior with regard to lag
If that's not the source of your problems, you need to eliminate it before
looking further.
The max and average apply rates are very different for the two standby's. (But
the slow one's faster. )
Transport and apply lag on fitsdb1... maybe this is just the mismatch between
redo and standby log sizes. They should all be the same size and you should
have one more standby log than the number of redo logs on each. But I guess you
know that already.
I should've asked for the ping times., but it's probably not relevant.
Database - itsdb2
Role: PHYSICAL STANDBY
Intended State: APPLY-ON
Transport Lag: 0 seconds (computed 0 seconds ago)
Apply Lag: 0 seconds (computed 0 seconds ago)
Average Apply Rate: 71.00 KByte/s
Active Apply Rate: 450.00 KByte/s
Maximum Apply Rate: 15.18 MByte/s
The standby below is the one that lags.
DGMGRL> show database verbose fitsdb1
Database - fitsdb1
Role: PHYSICAL STANDBY
Intended State: APPLY-ON
Transport Lag: 12 minutes 45 seconds (computed 12 seconds ago)
Apply Lag: 12 minutes 45 seconds (computed 12 seconds ago)
Average Apply Rate: 79.00 KByte/s
Active Apply Rate: 60.79 MByte/s
Maximum Apply Rate: 61.21 MByte/s
Regards
Join
On Fri, 4 Jan 2019, 15:41 Sandra Becker <sbecker6925@xxxxxxxxx wrote:
I had an error pop up that indicated a problem with a size difference between
the standby redo logs and the online redo logs. Standby on the primary was 10x
the size of online redo logs. All the logs on the standby were set up the same
as the online redo. I've corrected that just to be consistent and follow best
practices. While checking correcting the sizes, I noticed that the standby
that lags never assigns a standby redo log. Will be researching that next.
Sandy
On Fri, Jan 4, 2019 at 7:35 AM Sandra Becker <sbecker6925@xxxxxxxxx> wrote:
Yes, archiving the current log allows the standby to catch up.
DGMGRL> show configuration verbose
Configuration - itsdb_DG_CONFIG
Protection Mode: MaxPerformance
Members:
itsdb1 - Primary database
itsdb2 - Physical standby database
fitsdb1 - Physical standby database
Properties:
FastStartFailoverThreshold = '30'
OperationTimeout = '30'
TraceLevel = 'USER'
FastStartFailoverLagLimit = '30'
CommunicationTimeout = '180'
ObserverReconnect = '0'
FastStartFailoverAutoReinstate = 'TRUE'
FastStartFailoverPmyShutdown = 'TRUE'
BystandersFollowRoleChange = 'ALL'
ObserverOverride = 'FALSE'
ExternalDestination1 = ''
ExternalDestination2 = ''
PrimaryLostWriteAction = 'CONTINUE'
Fast-Start Failover: DISABLED
Configuration Status:
SUCCESS
DGMGRL> show database verbose itsdb1
Database - itsdb1
Role: PRIMARY
Intended State: TRANSPORT-ON
Instance(s):
its1
Properties:
DGConnectIdentifier = 'itsdb1'
ObserverConnectIdentifier = ''
LogXptMode = 'ASYNC'
RedoRoutes = ''
DelayMins = '0'
Binding = 'optional'
MaxFailure = '0'
MaxConnections = '1'
ReopenSecs = '300'
NetTimeout = '30'
RedoCompression = 'DISABLE'
LogShipping = 'ON'
PreferredApplyInstance = ''
ApplyInstanceTimeout = '0'
ApplyLagThreshold = '0'
TransportLagThreshold = '0'
TransportDisconnectedThreshold = '30'
ApplyParallel = 'AUTO'
StandbyFileManagement = 'AUTO'
ArchiveLagTarget = '0'
LogArchiveMaxProcesses = '30'
LogArchiveMinSucceedDest = '1'
DbFileNameConvert = '+DATA/ITSDB2/, +DATA/ITSDB1/'
LogFileNameConvert = '+DATA/ITSDB2/, +DATA/ITSDB1/'
FastStartFailoverTarget = ''
InconsistentProperties = '(monitor)'
InconsistentLogXptProps = '(monitor)'
SendQEntries = '(monitor)'
LogXptStatus = '(monitor)'
RecvQEntries = '(monitor)'
StaticConnectIdentifier =
'(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=pitsdbs01)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=itsdb1_DGMGRL)(INSTANCE_NAME=its1)(SERVER=DEDICATED)))'
StandbyArchiveLocation = '/backup/itsdb/archives'
AlternateLocation = ''
LogArchiveTrace = '0'
LogArchiveFormat = '%t_%s_%r.arc'
TopWaitEvents = '(monitor)'
Database Status:
SUCCESS
DGMGRL> show database verbose itsdb2
Database - itsdb2
Role: PHYSICAL STANDBY
Intended State: APPLY-ON
Transport Lag: 0 seconds (computed 0 seconds ago)
Apply Lag: 0 seconds (computed 0 seconds ago)
Average Apply Rate: 71.00 KByte/s
Active Apply Rate: 450.00 KByte/s
Maximum Apply Rate: 15.18 MByte/s
Real Time Query: OFF
Instance(s):
its2
Properties:
DGConnectIdentifier = 'itsdb2'
ObserverConnectIdentifier = ''
LogXptMode = 'ASYNC'
RedoRoutes = ''
DelayMins = '0'
Binding = 'optional'
MaxFailure = '0'
MaxConnections = '1'
ReopenSecs = '300'
NetTimeout = '30'
RedoCompression = 'DISABLE'
LogShipping = 'ON'
PreferredApplyInstance = ''
ApplyInstanceTimeout = '0'
ApplyLagThreshold = '0'
TransportLagThreshold = '0'
TransportDisconnectedThreshold = '30'
ApplyParallel = 'AUTO'
StandbyFileManagement = 'AUTO'
ArchiveLagTarget = '0'
LogArchiveMaxProcesses = '30'
LogArchiveMinSucceedDest = '1'
DbFileNameConvert = '+DATA/ITSDB1/, +DATA/ITSDB2/'
LogFileNameConvert = '+DATA/ITSDB1/, +DATA/ITSDB2/'
FastStartFailoverTarget = ''
InconsistentProperties = '(monitor)'
InconsistentLogXptProps = '(monitor)'
SendQEntries = '(monitor)'
LogXptStatus = '(monitor)'
RecvQEntries = '(monitor)'
StaticConnectIdentifier =
'(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=pitsdbs02)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=itsdb2_DGMGRL)(INSTANCE_NAME=its2)(SERVER=DEDICATED)))'
StandbyArchiveLocation = '/backup/itsdb/archives'
AlternateLocation = ''
LogArchiveTrace = '0'
LogArchiveFormat = '%t_%s_%r.arc'
TopWaitEvents = '(monitor)'
Database Status:
SUCCESS
The standby below is the one that lags.
DGMGRL> show database verbose fitsdb1
Database - fitsdb1
Role: PHYSICAL STANDBY
Intended State: APPLY-ON
Transport Lag: 12 minutes 45 seconds (computed 12 seconds ago)
Apply Lag: 12 minutes 45 seconds (computed 12 seconds ago)
Average Apply Rate: 79.00 KByte/s
Active Apply Rate: 60.79 MByte/s
Maximum Apply Rate: 61.21 MByte/s
Real Time Query: OFF
Instance(s):
fits1
Properties:
DGConnectIdentifier = 'fitsdb1'
ObserverConnectIdentifier = ''
LogXptMode = 'ASYNC'
RedoRoutes = ''
DelayMins = '0'
Binding = 'optional'
MaxFailure = '0'
MaxConnections = '1'
ReopenSecs = '300'
NetTimeout = '30'
RedoCompression = 'DISABLE'
LogShipping = 'ON'
PreferredApplyInstance = ''
ApplyInstanceTimeout = '0'
ApplyLagThreshold = '0'
TransportLagThreshold = '0'
TransportDisconnectedThreshold = '30'
ApplyParallel = 'AUTO'
StandbyFileManagement = 'AUTO'
ArchiveLagTarget = '0'
LogArchiveMaxProcesses = '30'
LogArchiveMinSucceedDest = '1'
DbFileNameConvert = '+DATA/ITSDB2/, +DATA/FITSDB1/'
LogFileNameConvert = '+DATA/ITSDB2/, +DATA/FITSDB1/'
FastStartFailoverTarget = ''
InconsistentProperties = '(monitor)'
InconsistentLogXptProps = '(monitor)'
SendQEntries = '(monitor)'
LogXptStatus = '(monitor)'
RecvQEntries = '(monitor)'
StaticConnectIdentifier =
'(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=fitsdbs1)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=fitsdb1_DGMGRL)(INSTANCE_NAME=fits1)(SERVER=DEDICATED)))'
StandbyArchiveLocation = '/backup/itsdb/archives'
AlternateLocation = ''
LogArchiveTrace = '0'
LogArchiveFormat = '%t_%s_%r.arc'
TopWaitEvents = '(monitor)'
Database Status:
SUCCESS
I may be missing something, but I didn't see any differences in the config
between the two standbys.
Sandy
On Fri, Jan 4, 2019 at 3:11 AM Neil Chandler <neil_chandler@xxxxxxxxxxx> wrote:
Sandy,
So if you do a manual "alter system archive log current" on the Primary, it
catches up?
I would look at the config parameters to compare the configuration. Could you
share the configuration info (db/server names suitably redacted):
dgmgrl> show configuration verbose
dgmgrl> show database verbose <primary|standby2|standby2>
regards
Neil Chandler
Database Guy, Knows Things.
_____
From: Sandra Becker <sbecker6925@xxxxxxxxx>
Sent: 03 January 2019 22:49
To: John Thomas
Cc: Andrew Kerber; Neil Chandler; oracle-l
Subject: Re: One primary with two physical standbys exhibiting different
behavior with regard to lag
My understanding is the network setup is the same between the standbys. I
didn't look at the network right away. :-) I made the changes suggested by
Neil, but I'm still seeing the delay. Before I did a manual log switch, the
delay was over 30 minutes. Not good for this critical production standby.
Sandy
On Thu, Jan 3, 2019 at 3:36 PM John Thomas <jt2354@xxxxxxxxx> wrote:
There's no excessive delay between your primary and the lagging standby is
there? Smaller pipe? Lots of network retries?
Probably the second thing you checked...
Regards,
John
On Thu, 3 Jan 2019 at 22:10, Sandra Becker <sbecker6925@xxxxxxxxx> wrote:
Thanks, Andrew. That's one of the first things I checked. It's the same on
both standbys.
Sandy
On Thu, Jan 3, 2019 at 2:47 PM Andrew Kerber <andrew.kerber@xxxxxxxxx> wrote:
Neil most likely spotted the problem. But you should also check to make sure
that the protection mode is the same on both standbys.If the instance that is
behind is using the maximum performance (async) mode it can run a ways behind
the primary.
On Thu, Jan 3, 2019 at 3:36 PM Neil Chandler <neil_chandler@xxxxxxxxxxx> wrote:
Sandy,
Have you checked the Standby Redo logs? There's a slight (annoying) change in
Oracle 12.1 onwards which means that Standby Redo logs get created with Thread
0 instead of Thread 1 by default (for a single instance database). Redo can
only use Standby Redo when the threads are the same. If this is RAC you need
Standby Redo for each thread - and you must have 1 more Standby Redo than
Online Redo for each thread.
By coincidence, I wrote a blog post about this 10 minutes ago.
https://chandlerdba.com/2019/01/03/data-guard-unexpected-lag/
regards
Neil Chandler
Database Guy. Knows Things.
_____
From: oracle-l-bounce@xxxxxxxxxxxxx <oracle-l-bounce@xxxxxxxxxxxxx> on behalf
of Sandra Becker <sbecker6925@xxxxxxxxx>
Sent: 03 January 2019 20:29
To: oracle-l
Subject: One primary with two physical standbys exhibiting different behavior
with regard to lag
Oracle 12.1.0.2
RHEL7
To begin with, I have not worked much at all with standby databases, so my
knowledge is somewhat lacking.
For business reasons, we have a primary database with two physical standbys.
Everything is configured in dgmgrl and enabled. Monitoring with EM13c is
reporting the lag times, so all looks good for basic setup and monitoring. We
seem to have significant lag at times on one of the standbys, as much as 20
minutes. When looking at v$managed_standby, we see the status as
"WAIT_FOR_LOG". The other standby never seems to be more that a few seconds
behind, if at all, and the status is "APPLYING_LOG".
Is this normal? I've been researching, but haven't found an answer yet. I
didn't create or start the standby databases, so I don't have any idea what was
actually done that could be causing this behavior. Any suggestions would be
appreciated.
Thank you,
--
Sandy B.
--
Andrew W. Kerber
'If at first you dont succeed, dont take up skydiving.'
--
Sandy B.
--
Sandy B.
--
Sandy B.
--
Sandy B.
