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CockroachDB troubleshooting series… define the process

After working with customers for about 18 months now, I am starting a blog series to write up the common issues seen while running CockroachDB. Diagnosis and treatment of issues when running on distributed database architectures like CockroachDB, closely mirror the process used in the medical community.

There are observed symptoms which leads to a diagnosis and finally a treatment to resolve the condition. Good troubleshooting methodology can help frame the problem which leads to better overall outcomes. This process is outlined below:

Scaling CockroachDB key generation… uuid, serial, and sequences

Overview

Primary keys are critical in any RDBMS in order to ensure the validity of data. Unlike other distributed SQL databases, CockroachDB is not sharded by primary key to distribute the data. Data is divided to ranges and distributed automatically among nodes in the cluster. CockroachDB ranges are sorted by the primary key values. So, while the value doesn’t define the distribution, the sorting of the values can have implications if you use sequences that increment values in a counter-like fashion. This will put stress on a single RANGE of data which scaling of a distributed application.

Azure IO Performance for the RDBMS DBA- Part I

With my upcoming session on “Migrating Oracle Workloads to Azure IaaS” this week at PASS Virtual Summit 2020, I wanted to take some time to dig deeper onto the performance side. The last thing you want to have happen is to migrate your database to the cloud and have it just screech to a halt.

Join Performance for UUID, STRING, and INTEGER with CockroachDB

overview

To continue on the UUID performance thread, I was recently asked by a customer how joins perform with various data types. I had not run a specific test, but suspected perform would be driven mostly by the size of the data types.

I wanted to verify my assumptions with real test data that shows the core performance of joins with CockroachDB.

the schema, data, and queries

For this test, two tables were created. The first table had one million rows and the second table had 200k matching primary keys for UUID, STRING, and INTEGER data types.

schema:

create table u1 (id uuid primary key);
create table u2 (id uuid primary key);

create table s1 (id string primary key);
create table s2 (id string primary key);

create table i1 (id integer primary key);
create table i2 (id integer primary key);

data load:

Video : Multitenant : Disk I/O (IOPS, MBPS) Resource Management for Pluggable Databases (PDBs)

In today’s video we’ll discuss how Resource Manager allows us to manage the disk I/O (IOPS, MBPS) usage in PDBs. This can be useful to stop a small number of PDBs using all disk IOPS and/or bandwidth on the server.

The video is based on the following article.

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Ingest format performance with UUID using CockroachDB

Recently, I have been working with customers that have been concerned about the performance of various UUID formats. Other products have various performance characteristics for inserting, generating and presenting UUID data.

For this blog, I ran a quick series of tests using jmeter insert data along with some simple SQL tests to generate UUID values. Hopefully, this will be helpful to better your understanding of UUID with CockroachDB.

UUID formats

Cockroach DB has four different ways data can be formatted for use with the UUID data type.

String format
'63616665-6630-3064-6465-616462656564'

Curly Brace format
'{63616665-6630-3064-6465-616462656564}'

Oracle REST Data Services (ORDS) : Database APIs – First Steps

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In my never ending quest for automation, I finally got round to looking at the Oracle REST Data Services (ORDS) Database APIs.

Video : Multitenant : Dynamic CPU Scaling – Resource Manager Control of CPU using CPU_COUNT and CPU_MIN_COUNT

In today’s video we’ll discuss how Resource Manager can control CPU usage in PDBs using the CPU_COUNT and CPU_MIN_COUNT parameters. Oracle call this Dynamic CPU Scaling. This can be useful to stop a small number of PDBs using all CPU resources assigned to the instance.

This video is based on the following article.

Video : Simple Oracle Document Access (SODA) for SQLcl

In today’s video we give a demonstration of Simple Oracle Document Access (SODA) for SQLcl. SODA is a feature of Oracle REST Data Services (ORDS),
but this allows to access the document store directly from SQLcl.

This video is based on the following article.

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Video : Simple Oracle Document Access (SODA) for PL/SQL

In today’s video we give a demonstration of Simple Oracle Document Access (SODA) for PL/SQL. SODA is a feature of Oracle REST Data Services (ORDS),
but this PL/SQL interface for SODA was introduced in Oracle Database 18c.

The video is based on this article.

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