"db file sequential read" latency during reads versus update activity
From: Hameed, Amir <Amir.Hameed_at_xerox.com>
Date: Thu, 8 Mar 2018 14:54:18 +0000
Message-ID: <DM5PR1101MB2347006C9F799B2C79C22656F4DF0_at_DM5PR1101MB2347.namprd11.prod.outlook.com>
I am running SLOB to gauge latency of the storage array. When I configure my test for SELECT only run (no updates), I see average latency of db file sequential read consistently around 3ms. However, as I start to add UPDATE activity to the run, I see average latency of db file sequential read go up in the vicinity of 5ms. Is the cause of this increase in latency due to the commit cleanouts phenomena? The database version is 12.1.0.2. My DB_CACHE size is set to 128M to drive physical IOs and I am running my tests with 64 concurrent users.
Date: Thu, 8 Mar 2018 14:54:18 +0000
Message-ID: <DM5PR1101MB2347006C9F799B2C79C22656F4DF0_at_DM5PR1101MB2347.namprd11.prod.outlook.com>
I am running SLOB to gauge latency of the storage array. When I configure my test for SELECT only run (no updates), I see average latency of db file sequential read consistently around 3ms. However, as I start to add UPDATE activity to the run, I see average latency of db file sequential read go up in the vicinity of 5ms. Is the cause of this increase in latency due to the commit cleanouts phenomena? The database version is 12.1.0.2. My DB_CACHE size is set to 128M to drive physical IOs and I am running my tests with 64 concurrent users.
Thanks,
Amir
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