From jwalthour@mac.com Thu, 14 Jun 2001 17:39:54 -0700 From: Jon Walthour Date: Thu, 14 Jun 2001 17:39:54 -0700 Subject: Re: CKPTs are not happening with FAST_START_IO_TARGET Message-ID: MIME-Version: 1.0 Content-Type: text/plain --MS_Mac_OE_3075396610_4810850_MIME_Part Content-type: text/plain; charset="US-ASCII" Content-transfer-encoding: 7bit Srinagesh: A couple of questions: 1. You have what seem to me to be many very large log groups. What reasons make this necessary? 2. Have you considered setting LOG_CHECKPOINT_INTERVAL to a much lower value that would compute to be less than the size of your redo logs so that checkpoints would be forced in the middle of your redo logs as well as at log switches? Forcing checkpoints within your log files reduces the time needed for instance recovery. 3. What about setting LOG_CHECKPOINT_TIMEOUT to a lower value for the same reasoning? 4. What have you found when setting the FAST_START_IO_TARGET parameter to a lower value? -- Jon Walthour, OCDBA Oracle DBA Computer Horizons Cincinnati, Ohio Organization: Fat City Network Services, San Diego, California Reply-To: ORACLE-L@fatcity.com Date: Thu, 14 Jun 2001 15:45:42 -0800 To: Multiple recipients of list ORACLE-L RDBMS: Oracle8i Enterprise Edition Release 8.1.7.0.0 - Production With the Partitioning option JServer Release 8.1.7.0.0 - Production OS: SunOS e6500a 5.6 Generic_105181-19 sun4u sparc SUNW,Ultra-Enterprise The init params are set as follows: .. db_block_size=8192 db_block_buffers=20000 fast_Start_io_target=5000 log_checkpoints_to_alert = TRUE log_checkpoint_timeout = 2147483647 log_checkpoint_interval = 999999999 .... We have 4 Redo log groups with 200M each. We have a requirement that the instance recovery must be done within 60 secs. So, we are trying to use the fast_Start_io_target param. The issue here is, we don't see any checkpoints being done (as seen in the alert logs as well as v$sysstat). THe only checkpoints that we see are the ones that happen during a log switch or if you issue "alter system checkpoint". Any ideas on why the checkpoints are not being performed. Thanks in advance. --MS_Mac_OE_3075396610_4810850_MIME_Part Content-type: text/html; charset="US-ASCII" Content-transfer-encoding: quoted-printable Re: CKPTs are not happening with  FAST_START_IO_TARGET Srinagesh:

A couple of questions:

1. You have what seem to me to be many very large log groups. What reasons = make this necessary?

2. Have you considered setting LOG_CHECKPOINT_INTERVAL to a much lower valu= e that would compute to be less than the size of your redo logs so that chec= kpoints would be forced in the middle of your redo logs as well as at log sw= itches? Forcing checkpoints within your log files reduces the time needed fo= r instance recovery.

3. What about setting LOG_CHECKPOINT_TIMEOUT to a lower value for the same = reasoning?

4. What have you found when setting the FAST_START_IO_TARGET p= arameter to a lower value?

--

Jon Walthour, OCDBA
Oracle DBA
Computer Horizons
Cincinnati, Ohio


From: Srinagesh Battula <sbattula@vcommerce.com>
Organization: Fat City Network Services, San Diego, Cali= fornia
Reply-To: ORACLE-L@fatcity.com
Date: Thu, 14 Jun 2001 15:45:42 -0800
To: Multiple recipients of list ORACLE-L <ORACLE-L@fatcity.com>= ;
Subject: CKPTs are not happening with  FAST_START_IO_TARGET



RDBMS:
Oracle8i Enterprise Edition Release 8.1.7.0.0 - Production <= BR> With the Partitioning option
JServer Release 8.1.7.0.0 - Production

OS:
SunOS e6500a 5.6 Generic_105181-19 sun4u sparc SUNW,Ultra-En= terprise

The init params are set as follows:
..
db_block_size=3D8192
db_block_buffers=3D20000
fast_Start_io_target=3D5000
log_checkpoints_to_alert =3D TRUE
log_checkpoint_timeout =3D 2147483647
log_checkpoint_interval =3D 999999999
....

We have 4 Redo log groups with 200M each.

We have a requirement that the instance recovery must be don= e within 60 secs.
So, we are trying to use the fast_Start_io_target param.
The issue here is, we don't see any checkpoints being done (as seen in the = alert logs as well as v$sysstat). THe only checkpoints that we see are the o= nes that happen during a log switch or if you issue "alter system check= point".

Any ideas on why  the checkpoints are not being perform= ed.

Thanks in advance.

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