IT | Linux | Databases | Infrastructure https://seiler.us I spent the better part of 3 days banging my head against my desk trying to sort out HTTP authentication for Chef’s remote_file resource. The method itself is straight-forward: you have to Base64 encode the username and password and specify that in a hash for the headers parameter for remote_file.... Tue, 15 Mar 2022 00:00:00 -0500 https://seiler.us/2022-03-15-chef-encode-lazy-vars/ https://seiler.us/2022-03-15-chef-encode-lazy-vars/ I recently had a replica that was restarted but was having trouble getting caught up enough to enable streaming replication. The WAL archive restore & recovery was taking just a little too long. The pgBackRest team offered these very helpful tips and I wanted to share them with all of... Sun, 23 May 2021 00:00:00 -0500 https://seiler.us/2021-05-23-speeding-up-pgbackrest-recovery/ https://seiler.us/2021-05-23-speeding-up-pgbackrest-recovery/ We recently enabled unattended-upgrades on our Ubuntu 18.04 LTS (Bionic) servers, including our PostgreSQL hosts. By default, unattended-upgrades will ignore PGDG packages (where all of our PostgreSQL packages come from), so I had assumed we wouldn’t have any interruptions due to apt installing updates and triggering a database restart. One... Wed, 18 Nov 2020 00:00:00 -0600 https://seiler.us/2020-11-18-unattended-upgrades/ https://seiler.us/2020-11-18-unattended-upgrades/ Many RDBMSes use sequence caching to pre-generate sequence values in advance and store them in memory, allowing them to return new values quickly. If you are doing a lot of inserts that each call the sequence to get the next value, sequence caching is a good thing. Having to wait... Tue, 02 Oct 2018 00:00:00 -0500 https://seiler.us/2018-10-02-sequence-caching-oracle-vs-postgresql/ https://seiler.us/2018-10-02-sequence-caching-oracle-vs-postgresql/ A Story of the Laziest User Recreation Script Ever - Encountering the NULL Recently I wanted to write a script to drop and recreate app users, keeping their existing passwords. For this post we’ll say I have 3 users: bigsam, marco, and rhino. My first attempt something like this: postgres=# select 'CREATE USER '||usename||' ENCRYPTED PASSWORD '''||passwd||''';' postgres-# from pg_shadow... Sun, 01 Jul 2018 00:00:00 -0500 https://seiler.us/2018-07-01-null-passwords/ https://seiler.us/2018-07-01-null-passwords/ What NOT to expect when you're expecting. - One of the big changes I came upon as I transitioned from Oracle to PostgreSQL was how privileges are handled. In Oracle, an object’s schema also determines its owner, as the schema is generally that user’s objects. PostgreSQL disassociates schemas from users. Schemas do have owners, but a given user... Tue, 05 Jun 2018 00:00:00 -0500 https://seiler.us/2018-06-05-alter-default-privs/ https://seiler.us/2018-06-05-alter-default-privs/ ACLs FTW - The Incident While cleaning up some obsolete user accounts, one of my DROP USER commands failed with: ERROR: 2BP01: role "joe" cannot be dropped because some objects depend on it Querying the usual catalog views, I couldn’t find any objects owned by this user. That’s when I noticed the line... Fri, 11 May 2018 00:00:00 -0500 https://seiler.us/2018-05-11-usage-prevents-drop-user/ https://seiler.us/2018-05-11-usage-prevents-drop-user/ Yet Another Beautiful Jekyll Site! - If you’re reading this, then the migration has worked. My blog is now hosted via GitHub Pages. Many thanks to Kris Rice for his Blogger migration blog post and source code to get me set. I might move some other stuff under this site as well, namely my notes currently... Fri, 11 May 2018 00:00:00 -0500 https://seiler.us/2018-05-11-moved-to-github-pages/ https://seiler.us/2018-05-11-moved-to-github-pages/ This morning I received an UPDATE statement from a developer that I was testing. It ran without errors but then I saw that it updated 5 rows when it should have only updated 3. The reason gave me a little shock so I whipped up a simple test-case to reproduce... Mon, 30 Apr 2018 12:55:00 -0500 https://seiler.us/2018-04-30-beware-sort-of-ambiguous-column-names/ https://seiler.us/2018-04-30-beware-sort-of-ambiguous-column-names/ A few months ago I was doing some testing on a development PostgreSQL database and watching the postgresql server log (akin to Oracle's alert log). I was skimming for lines relevant to my testing when I noticed something chilling:LOG:  statement: alter user john password 'IloveDBAs';The username and password have obviously... Sat, 14 Apr 2018 11:53:00 -0500 https://seiler.us/2018-04-14-how-not-to-change-passwords-in/ https://seiler.us/2018-04-14-how-not-to-change-passwords-in/ Note: Yes I re-(ab)used the title.As some of you may know (if you follow me on twitter), after 16 years as an Oracle DBA, I made a career shift last summer. I hung up the Oracle spurs (and that sweet Oracle Ace vest) and threw on a pair of PostgreSQL... Fri, 09 Feb 2018 14:31:00 -0600 https://seiler.us/2018-02-09-the-transition-or-how-i-learned-to-stop/ https://seiler.us/2018-02-09-the-transition-or-how-i-learned-to-stop/ We use VictorOps for our paging/notification system, and we're pretty happy with it so far. On the DBA team, we've just been using a simple email gateway to send notifications from Oracle Enterprise Manager (EM) to VictorOps. Even then, we can only send the initial notification and not really send... Thu, 28 Jan 2016 11:55:00 -0600 https://seiler.us/2016-01-28-sending-notifications-from-oracle/ https://seiler.us/2016-01-28-sending-notifications-from-oracle/ $ uptime 16:36:42 up 4 days, 12:28, 6 users, load average: 1029.20, 995.42, 865.77 See this and that (requires RedHat subscription) for details. And defrag your XFS volumes. Tue, 10 Nov 2015 16:03:00 -0600 https://seiler.us/2015-11-10-just-xfs-things/ https://seiler.us/2015-11-10-just-xfs-things/ Earlier this month we began getting frequent email warnings from our EM12c server that some agents were experiencing read time outs. Then we saw that the emagent java process was using A LOT of CPU, regularly around 500% but sometimes as high as 800% as seen from "top". Restarting the... Tue, 21 Jul 2015 16:50:00 -0500 https://seiler.us/2015-07-21-the-leap-second-is-no-laughing-matter/ https://seiler.us/2015-07-21-the-leap-second-is-no-laughing-matter/ Last week we began testing a copy of our production database on Oracle 12c (12.1.0.2). This past weekend we were alerted that the disk holding our ADR diagnostic directory was near full. We noticed some pretty big (and recent) trace files there. Then it happened twice more. This last time... Tue, 21 Jul 2015 12:12:00 -0500 https://seiler.us/2015-07-21-upgrade-to-oracle-12c-get-huge-trace/ https://seiler.us/2015-07-21-upgrade-to-oracle-12c-get-huge-trace/ When I have to run SQL scripts, I prefer to do it via executable ksh scripts (I use ksh because it's usually an Oracle pre-requisite so I can rely on it being installed). One thing that I've just recently started adding into my scripts is exiting sqlplus on error and... Tue, 06 Jan 2015 15:32:00 -0600 https://seiler.us/2015-01-06-returning-error-codes-from-sqlplus-to/ https://seiler.us/2015-01-06-returning-error-codes-from-sqlplus-to/ I recently had need to make a copy of an image copy in Oracle rman. Since it wasn't immediately obvious to me, I thought it was worth sharing once I had it sorted out. I was familiar with making a backup of a backup, but had never thought about making... Wed, 12 Nov 2014 10:13:00 -0600 https://seiler.us/2014-11-12-making-copies-of-copies-with-oracle-rman/ https://seiler.us/2014-11-12-making-copies-of-copies-with-oracle-rman/ Just wanted to share a quick story with everyone. As I was in the airport waiting to fly to Oracle OpenWorld this year, I noticed a flurry of emails indicating that part of our storage infrastructure for our standby production database had failed. Long story short, my co-workers did a... Tue, 04 Nov 2014 22:28:00 -0600 https://seiler.us/2014-11-04-the-importance-of-backups-cautionary/ https://seiler.us/2014-11-04-the-importance-of-backups-cautionary/ We here at Seilerwerks Industries (not really) have been using snapshot standby databases to refresh an array of unit test databases from a common primary. During the business day, these would be converted to snapshot standby databases for testing, then overnight they are converted back to physical standby and recovered... Wed, 22 Oct 2014 23:00:00 -0500 https://seiler.us/2014-10-22-ora-16534-when-converting-tofrom/ https://seiler.us/2014-10-22-ora-16534-when-converting-tofrom/ File this one under the misleading-errors department. One of my developers was working with a new queue. He pinged me when he got this error trying to create a job that used the queue:ERROR at line 1:ORA-27373: unknown or illegal event source queueORA-06512: at "SYS.DBMS_ISCHED", line 124ORA-06512: at "SYS.DBMS_SCHEDULER", line... Wed, 01 Oct 2014 23:07:00 -0500 https://seiler.us/2014-10-01-advanced-queue-quickie-errors-and/ https://seiler.us/2014-10-01-advanced-queue-quickie-errors-and/