rman backup slow even after patching it

From: Beckstrom, Jeffrey <jbeckstrom_at_gcrta.org>
Date: Mon, 15 Aug 2022 17:37:13 +0000
Message-ID: <DM6PR09MB4677FB54C5E31A814C2E22F8DF689_at_DM6PR09MB4677.namprd09.prod.outlook.com>

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

--
http://www.freelists.org/webpage/oracle-l

Received on Mon Aug 15 2022 - 19:37:13 CEST