RE: [EXTERNAL] Re: rman backup slow even after patching it

From: Beckstrom, Jeffrey <jbeckstrom_at_gcrta.org>
Date: Tue, 23 Aug 2022 12:59:44 +0000
Message-ID: <DM6PR09MB4677914391FBD3525B2ED3A6DF709_at_DM6PR09MB4677.namprd09.prod.outlook.com>

Disk using RMAN.

From: David Barbour <david.barbour1_at_gmail.com> Sent: Tuesday, August 23, 2022 8:58 AM
To: Beckstrom, Jeffrey <jbeckstrom_at_gcrta.org> Cc: niall.litchfield_at_gmail.com; oracle-l_at_freelists.org Subject: Re: [EXTERNAL] Re: rman backup slow even after patching it

Jeffrey - What is your target? Tape/Disk/Cloud? Are you using any type of third-party software or is it straight-up RMAN?

On Tue, Aug 23, 2022 at 6:42 AM Beckstrom, Jeffrey <jbeckstrom_at_gcrta.org<mailto:jbeckstrom_at_gcrta.org>> wrote: 50 to 100% slower

From: niall.litchfield_at_gmail.com<mailto:niall.litchfield_at_gmail.com> <niall.litchfield_at_gmail.com<mailto:niall.litchfield_at_gmail.com>> Sent: Monday, August 22, 2022 11:28 AM
To: Beckstrom, Jeffrey <jbeckstrom_at_gcrta.org<mailto:jbeckstrom_at_gcrta.org>> Cc: oracle-l_at_freelists.org<mailto:oracle-l_at_freelists.org> Subject: [EXTERNAL] Re: rman backup slow even after patching it

What does "slow" mean in this context?

On Mon, Aug 15, 2022 at 6:37 PM Beckstrom, Jeffrey <jbeckstrom_at_gcrta.org<mailto:jbeckstrom_at_gcrta.org>> wrote: In 19.14, rman backup significantly slower than in 11g. This morning I put on some RMAN patches to no effect. In the rman trace file from a running backup I see:

Adjusting buffer count to honor available PGA; old bufcnt: 4, new bufcnt: 2, pga_agg_limit: 0, pga_agg_target: 0, pga_agg_used: 892876434, pga_available: 0
Adjusting buffer count to honor available PGA; old bufcnt: 4, new bufcnt: 2, pga_agg_limit: 0, pga_agg_target: 0, pga_agg_used: 892876434, pga_available: 0
Adjusting buffer count to honor available PGA; old bufcnt: 5, new bufcnt: 2, pga_agg_limit: 0, pga_agg_target: 0, pga_agg_used: 892876434, pga_available: 0
Adjusting buffer count to honor available PGA; old bufcnt: 6, new bufcnt: 2, pga_agg_limit: 0, pga_agg_target: 0, pga_agg_used: 892876434, pga_available: 0
Adjusting buffer count to honor available PGA; old bufcnt: 4, new bufcnt: 2, pga_agg_limit: 0, pga_agg_target: 0, pga_agg_used: 892876434, pga_available: 0
Adjusting buffer count to honor available PGA; old bufcnt: 5, new bufcnt: 2, pga_agg_limit: 0, pga_agg_target: 0, pga_agg_used: 892876434, pga_available: 0
Adjusting buffer count to honor available PGA; old bufcnt: 8, new bufcnt: 2, pga_agg_limit: 0, pga_agg_target: 0, pga_agg_used: 892876434, pga_available: 0
Adjusting buffer count to honor available PGA; old bufcnt: 16, new bufcnt: 2, pga_agg_limit: 0, pga_agg_target: 0, pga_agg_used: 892876434, pga_available: 0

Backup envisage an unusual situation due to PGA memory availability: we are using only 2 read threads (instead of 9) for the current backup session Adjusting buffer count to honor available PGA; old bufcnt: 4, new bufcnt: 2, pga_agg_limit: 0, pga_agg_target: 0, pga_agg_used: 913692181, pga_available: 0

Pga_aggregate targe is set at the cdb to a value. At the pdb level it is 0. Pga_aggregate_limit is not set anywhere.

Do I need to set the pga_aggregate limit?

Do I need to set both parameters at the PDB level?

Jeffrey Beckstrom
Greater Cleveland Regional Transit Authority 1240 W. 6th Street
Cleveland, Ohio 44113

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Niall Litchfield
Oracle DBA
http://www.orawin.info<https://gcc02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.orawin.info%2F&data=05%7C01%7Cjbeckstrom%40gcrta.org%7C5101afaf79a249c948da08da85072490%7Cebe8e20736ec47f48cb8f5f757605f5d%7C1%7C0%7C637968562983105085%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=45BeWVdCZhZHiq2zjelQuZKKe%2BIU%2FwjMMOvostkAKXI%3D&reserved=0>

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http://www.freelists.org/webpage/oracle-l Received on Tue Aug 23 2022 - 14:59:44 CEST