Turning a streaming standby into a hot-standby

[Axel Rau]

Hi dbas,

I changed hot_standby to "on" on the standby and learned on restart:
"hot standby is not possible because wal_level was not set to ""hot_standby"" on the master server"
After restarting the master with "wal_level = hot_standby",
I'm still getting the same error message on the standby.
This is 9.1.2.

What am I doing wrong?

Axel
---
PGP-Key:29E99DD6 ☀ [phone] ☀ computing @ chaos claudius

[Fujii Masao]

Post by Axel Rau
Hi dbas,
"hot standby is not possible because wal_level was not set to ""hot_standby"" on the master server"
After restarting the master with "wal_level = hot_standby",
I'm still getting the same error message on the standby.
This is 9.1.2.
What am I doing wrong?

After setting wal_level to hot_standby in the master, you need to take
a fresh base backup from the master onto the standby, and start the
standby from that backup.

The standby with hot_standby=on needs the backup which was backed
up from the master with wal_level=hot_standby.

Regards,

[Axel Rau]

Post by Fujii Masao

Post by Axel Rau
Hi dbas,
"hot standby is not possible because wal_level was not set to ""hot_standby"" on the master server"
After restarting the master with "wal_level = hot_standby",
I'm still getting the same error message on the standby.
This is 9.1.2.
What am I doing wrong?

After setting wal_level to hot_standby in the master, you need to take
a fresh base backup from the master onto the standby, and start the
standby from that backup.
The standby with hot_standby=on needs the backup which was backed
up from the master with wal_level=hot_standby.

Are you sure?
I just turned off hot_standby, brought up the standby and let it catch up until it started streaming.
I then turned on again hot_standby and the standby started successfully:
---
000,"recovery restart point at 8/C05E7AD8","last completed transaction was at log time 2012-11-08 17:24:27.007198+00",,,,,,,,""
000,"database system is shut down",,,,,,,,,""
00,"logger shutting down",,,,,,,,,""
,"database system was shut down in recovery at 2012-11-08 17:24:37 GMT",,,,,,,,,""
,"entering standby mode",,,,,,,,,""
00,"checkpoint record is at 8/C05E7B10",,,,,,,,,""
00,"redo record is at 8/C05E7AD8; shutdown FALSE",,,,,,,,,""
00,"next transaction ID: 0/692227; next OID: 596645",,,,,,,,,""
00,"next MultiXactId: 187; next MultiXactOffset: 388",,,,,,,,,""
00,"oldest unfrozen transaction ID: 665, in database 1",,,,,,,,,""
00,"transaction ID wrap limit is 2147484312, limited by database with OID 1",,,,,,,,,""
00,"resetting unlogged relations: cleanup 1 init 0",,,,,,,,,""
000,"initializing for hot standby",,,,,,,,,""
0000,"redo starts at 8/C05E7AD8",,,,,,,,,""
,00000,"recovery snapshots are now enabled",,,,,"xlog redo running xacts: nextXid 692227 latestCompletedXid 692226 oldestRunningXid 692227",,,,""
0000,"consistent recovery state reached at 8/C068C618",,,,,,,,,""
0000,"invalid record length at 8/C068C618",,,,,,,,,""
,"database system is ready to accept read only connections",,,,,,,,,""
,"streaming replication successfully connected to primary",,,,,,,,,""
0000,"connection received: host=[local]",,,,,,,,,""
---
Looks like a valid streaming standby to me.
What do you mean?

Axel
---
PGP-Key:29E99DD6 ☀ [phone] ☀ computing @ chaos claudius

[Fujii Masao]

Post by Axel Rau

Post by Fujii Masao

Post by Axel Rau
Hi dbas,
"hot standby is not possible because wal_level was not set to ""hot_standby"" on the master server"
After restarting the master with "wal_level = hot_standby",
I'm still getting the same error message on the standby.
This is 9.1.2.
What am I doing wrong?

After setting wal_level to hot_standby in the master, you need to take
a fresh base backup from the master onto the standby, and start the
standby from that backup.
The standby with hot_standby=on needs the backup which was backed
up from the master with wal_level=hot_standby.

Are you sure?
I just turned off hot_standby, brought up the standby and let it catch up until it started streaming.
---
000,"recovery restart point at 8/C05E7AD8","last completed transaction was at log time 2012-11-08 17:24:27.007198+00",,,,,,,,""
000,"database system is shut down",,,,,,,,,""
00,"logger shutting down",,,,,,,,,""
,"database system was shut down in recovery at 2012-11-08 17:24:37 GMT",,,,,,,,,""
,"entering standby mode",,,,,,,,,""
00,"checkpoint record is at 8/C05E7B10",,,,,,,,,""
00,"redo record is at 8/C05E7AD8; shutdown FALSE",,,,,,,,,""
00,"next transaction ID: 0/692227; next OID: 596645",,,,,,,,,""
00,"next MultiXactId: 187; next MultiXactOffset: 388",,,,,,,,,""
00,"oldest unfrozen transaction ID: 665, in database 1",,,,,,,,,""
00,"transaction ID wrap limit is 2147484312, limited by database with OID 1",,,,,,,,,""
00,"resetting unlogged relations: cleanup 1 init 0",,,,,,,,,""
000,"initializing for hot standby",,,,,,,,,""
0000,"redo starts at 8/C05E7AD8",,,,,,,,,""
,00000,"recovery snapshots are now enabled",,,,,"xlog redo running xacts: nextXid 692227 latestCompletedXid 692226 oldestRunningXid 692227",,,,""
0000,"consistent recovery state reached at 8/C068C618",,,,,,,,,""
0000,"invalid record length at 8/C068C618",,,,,,,,,""
,"database system is ready to accept read only connections",,,,,,,,,""
,"streaming replication successfully connected to primary",,,,,,,,,""
0000,"connection received: host=[local]",,,,,,,,,""
---
Looks like a valid streaming standby to me.
What do you mean?

Yeah, that's another way to fix the situation that you encountered.
IIRC, when the standby with hot_standby=on starts up, it needs the
checkpoint WAL record which was generated by the master with
wal_level=hot_standby. In your way, that checkpoint WAL record was
streamed from the master to the standby while hot_standby is being
disabled. So you can start up the standby with hot_standbfy=on.

Regards,