Brian Peasland

Author's posts

Dec 08

Fast Split Partitioning

I have a partitioned table for some application logging. A few years ago, I partitioned the table with one partition per month. As we near 2016, its time for me to add partitions for the new year. The partitioned table has, as its last two partitions, the partition for December 2015 and a partition using …

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Dec 02

SQLT in 12c Can’t Gather Stats

After upgrading to 12c, I did have some issues where processing in our database was running into the following errors: ORA-20000: Unable to gather statistics concurrently: insufficient privileges The fix was pretty easy. I found information on Tim’s Oracle Base website on the workaround here: https://oracle-base.com/articles/12c/concurrent-statistics-collection-12cr1 Today I tried to run SQLT’s sqlxtract script to help …

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Nov 30

cd: -M: invalid option

I’m trying to clean up trace files on one of my RAC testbeds. Oracle Corp was gracious enough to name the database “-MGMTDB” for me to give me a nice challenge (dripping with sarcasm). Here I am in my DIAGNOTIC_DEST and we can see two databases. [oracle@host01 trace]$ cd /u01/app/oracle/diag/rdbms [oracle@host01 rdbms]$ ls -l total …

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Nov 16

Dynamic Sampling Killing Me in 12c

Eleven days ago, I blogged about how Adaptive Dynamic Stats was consuming resources in my production RAC databases. After putting out that fire, I was on to examine some poorly performing queries being reported by our QA people in Test and other non-production databases. I did as any good Oracle DBA would do. I gathered …

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Nov 16

Lighty Purchasing Adventure

Those that follow me on Twitter and in this blog know that I really like Orachrome’s Lighty for performance tuning. I prefer this over Enterprise Manager. I’ve gotten to the point where I get depressed if Lighty isn’t available to me and I am forced to use EM in its place. Don’t get me wrong, …

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Nov 11

Addnode resolv.conf Failures

Today I was trying to add a new node to an existing Oracle RAC cluster. Grid Infrastructure is version 12.1.0.2 running on Oracle Linux 5.11. I ran through the usual Cluster Verification Utility (CVU) checks and all checks passed. To add the node, I issued the following command from the $GRID_HOME/addnode directory. ./addnode.sh -silent “CLUSTER_NEW_NODES={newnode}” “CLUSTER_NEW_VIRTUAL_HOSTNAMES={newnode-vip}” …

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Nov 05

Adaptive Dynamic Stats Kills Performance in 12.1.0.2 RAC

After a recent upgrade to 12.1.0.2, I’ve been working on a number of performance issues. Many such issues are related to poor SQL and a number of issues I’ve resolved I’ve proven were issues in the old 11.2.0.4 release. This just means it’s always been an issue. But people are taking the opportunity of the …

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Oct 28

My OOW15 Trip Is Complete

I’m leaving Open World 2015 a day early. I managed to pack in an awful lot of activity into the three days I was here and I met up with some very nice people. I expect that my OOW experience was similar to many others. There was so much to do and not enough time. …

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Oct 28

Cursor Obsoletion Dump

After our recent upgrades to Oracle 12.1.0.2, we noticed a few non-production databases that were filling up the DIAGNOSTIC_DEST. There were huge trace files in there which contained this type of information: —– Cursor Obsoletion Dump sql_id=6aca4drrt76x3 —– Parent cursor obsoleted 1 time(s). It appears this is a known bug in 12.1.0.2. Oracle turned on …

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Oct 26

Oracle 12.2 Sharding

I’ve been working with MongoDB a bit and one of the things I like about it is how sharding helps the platform achieve high performance. MongoDB is not the only database platform that uses sharding, just one of the more mainstream ones. While I’ve been working with MongoDB and admiring sharding and the ability to …

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