Everything our consultants learn while running databases for customers: Oracle, PostgreSQL, SQL Server, MySQL, MariaDB, MongoDB and Delphix. Expect hands-on posts about installation, day-to-day administration, backup and recovery, performance tuning, replication and upgrades.
By Franck Pachot . I usually don’t advice to set CURSOR_SHARING=FORCE but imagine your application requires it, you forgot it (or tried to do without) on migration and then everything is slow. You want to change it, but when does it take effect? New execution? New parsing? New session? EXACT I have the default value where parent cursor is shared…
By Franck Pachot . A few screenshots and a link here. Sysadmins do not like ASM because they don’t have the tools they like to manage the disks. For example, they don’t want to run SQL queries to check performance, and asmcmd iostat is quite limited. Here is a nice way to get I/O statistics easily from command line. The…
This time, I will talk about distributed availability groups. What’s that? In short, a group of availability groups. Sounds good right? But in which cases may we need such architecture? Firstly, let’s say that distributed availability groups will run on the top of two distinct availability groups meaning that they reside on two distinct WSFCs with their own quorum and…
In this blog I would like to talk about two new features shipped with SQL Server 2016 for AlwaysOn availability groups. The first one concerns the new direct seeding capability and the seconde one introduces distributed availability groups (DAG). I will talk about the second one in a next blog post. First of all, let’s talk about direct seeding. At the first…
By Franck Pachot . I’ve described in previous posts how the 12c online datafile move works: your session process do the copy and tells other writers (dbwr and direct-path inserts) to write blocks to both files (old one and new one for blocks that have already been copied). Readers read old file until the copy is completed. The target file…
When you have less CPU threads than the number of processes that has something to run in CPU, the OS will schedule them to share the CPU resource. Increasing the workload at that point will not increase the throughput because you have reached the capacity of your system, and response time will increase because of queuing. Actually, performance will even…
By Franck Pachot . ORA_LPENABLE To let Oracle use Large Pages on Windows, you need to define a registry string ORA_LPENABLE=1. This will enable large pages for all instance so it’s probably better to do it at instance level with ORA_SID_LPENABLE, especially if you have an ASM instance on your server. Note that large pages is a recommandation for an…
By Mouhamadou Diaw Nowadays, replicating data is very important. Many tools exist in the market (Goldengate, Dbvisit …). In this article we talk about a Dell Product tool that can be used for data replication: SharePlex. The goal is to show how it is easy to setup a SharePlex environment for replicating data. After installing the software we will replicate scott schema…
I was very surprise with this new version of SQL Server and his installation. The first point is that we don’t need any more to install the framework .Net 3.51 manually… The second main point is the configuration of TempDB directly in the Database Engine Configuration. In the installation wizard, the number of files is automatically based on the number…
In this blog post I just want to clarify values that we may find from the is_failover_ready column of the sys.dm_hadr_database_replica_cluster_states DMV. A couple of days ago, I had an interesting discussion with one of my customers during which he explained he was not confident about the availability group state after facing some unavailability issues. The main source of uncertainty…
In December 2015, my colleague Vincent did a test with additional column with Oracle GoldenGate 12.2. Hervé & Vincent asked me to do the same test with Attunity Replicate between Oracle and SQL Server. For the story, Hervé does the test with a previous version here. I create a task and select the Scott schema. I run the replication On…
By a customer, we faced the question: how to backup and restore a replication task in Attunity Replicate? We don’t see any button or menu into the administration web console and in the Guide line, we haven’t really a section about Backup and Restore ??? How to back up a task? The backup is, in reality, an export… The first…
