index

Elasticsearch – Data lifecycle management

Elasticsearch is a very versatile platform that supports a variety of use cases and provides great flexibility around data organization. After a global overview on Elastic Stack, understanding Elasticsearch terminologies, and(…)

SQL Server: Heap page deallocation and IndexOptimize

Introduction HEAP tables are a type of data structure that, unlike a clustered index table, does not have a specific ordering of its rows, making them faster to insert and delete data. They are often used for temporary(…)

Alfresco – Documents are searchable only after 3min

I had a case at a customer recently where newly uploaded documents into Alfresco would always be searchable but only after 2min45s to 3min. The environment in question is an Alfresco Content Services 7.1 with High Availability (Repository and Share(…)

Elastic (ELK) Stack – Elasticsearch Terminologies

In a previous blog, we got an overview on Elastic Stack (Elasticsearch, Logstash, Kibana, and Beets), in next blogs I will go through all these components to understand them, today we will go more in deep in(…)

DynamoDB / Aurora: sparse and partial indexes

By Franck Pachot . In a previous post I tried to build a glossary about Amazon DynamoDB terms that look like relational database terms, but with a different technical meaning. Here is more about it. If(…)

Amazon DynamoDB: a r(el)ational Glossary

By Franck Pachot . There are many NoSQL databases. And, because SQL is an ISO standard, “No SQL” also means “No Standard”. Many have a similar API and similar objects, but with completely different names. Today, NoSQL databases are(…)

Amazon DynamoDB: the cost of indexes

By Franck Pachot . That’s common to any data structure, whether it is RDBMS or NoSQL, indexes are good to accelerate reads but slow the writes. This post explains the consequences of adding indexes in DynamoDB. Secondary Indexes What(…)

RDBMS (vs. NoSQL) scales the algorithm before the hardware

By Franck Pachot . In The myth of NoSQL (vs. RDBMS) “joins dont scale” I explained that joins actually scale very well with an O(logN) on the input tables size, thanks to B*Tree index access,(…)

Oracle non-linguistic varchar2 columns to order by without sorting

By Franck Pachot . Sorting data is an expensive operation and many queries declare an ORDER BY. To avoid the sort operation you can build an index as it maintains a sorted structure. This helps with Top-N queries as(…)

Oracle 12c – pre-built join index

By Franck Pachot . This post is part of a series of small examples of recent features. I’m running this in the Oracle 20c preview in the Oracle Cloud. I have created a few tables in the(…)