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

I'll repeat just this snippet from my earlier remarks:  

Without measuring a damn thing, the first thing I would do is check whether the "mount" strings for your destination are different between 11 and 19.  

Your 11 install was probably around long enough that someone optimized how the disk was mounted, and if you have anything different with the environment of the 19 install it could easily account for 50 to 100% slower.  

Good luck!  

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Beckstrom, Jeffrey
Sent: Tuesday, August 23, 2022 9:00 AM
To: David Barbour
Cc: niall.litchfield_at_gmail.com; oracle-l_at_freelists.org Subject: RE: [EXTERNAL] Re: rman backup slow even after patching it  

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> wrote:

50 to 100% slower  

From: niall.litchfield_at_gmail.com <niall.litchfield_at_gmail.com> Sent: Monday, August 22, 2022 11:28 AM
To: Beckstrom, Jeffrey <jbeckstrom_at_gcrta.org> Cc: 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> 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
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