Tag: INDEX

Feed: Planet PostgreSQL. In a previous post I stored tags and groups as arrays in the posts table. I created GIN indexes on them, but without the possibility to add the timestamp to it. To optimize queries on a list of tags, or groups, within a range of date, I added secondary tables, automatically maintained by triggers. This was much more efficient in YugabyteDB because this additional index is like an index (tables are stored as LSM Trees rather than heap tables) and because, without this, the Rows Removed by Filter from the GIN index are very expensive in a ... Read More

Feed: Planet NoSQL. Author: Keshav Murthy. In Couchbase, data is always partitioned using the consistent hash value of the document key into buckets, which are stored on the data nodes. Couchbase Global Secondary Index (GSI) abstracts the indexing operations and runs as a distinct service within the Couchbase data platform. When a single index can cover a whole type of documents, everything is good. But there are cases where you’d want to partition an index.Capacity: You want increased capacity because a single node is unable to hold a big index.Query-ability: You want to avoid rewriting the query to work with manual partitioning of the ... Read More

Feed: AWS Big Data Blog. When it comes to time-series data, it’s more common to access new data than existing data, such as the last four hours or one day. Often, application teams must maintain multiple indexes for diverse data workloads, which bring new requirements to set up a custom solution to manage the index lifecycles. This becomes tedious as the indexes grow, and it results in housekeeping overhead. Amazon OpenSearch Service (successor to Amazon Elasticsearch Service) enables you to automate recurring index management activities. This avoids having to use any additional tools to manage the index lifecycles. Index State Management ... Read More

Feed: AWS Big Data Blog. Amazon OpenSearch Service (successor to Amazon Elasticsearch Service) recently announced support for Index Transforms. You can use Index Transforms to extract meaningful information from an existing index, and store the aggregated information in a new index. The key benefit of Index Transforms is faster retrieval of data by performing aggregations, grouping in advance, and storing those results in summarized views. For example, you can run continuous aggregations on ecommerce order data to summarize and learn the spending behaviors of your customers. With Index Transforms, you have the flexibility to select specific fields from the source index. You can ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . MariaDB has support for full-text indexing and searching: A full-text index in MariaDB is an index of type FULLTEXT, and it allows more options when searching for portions of text from a field. Full-text indexes can be used only with MyISAM and Aria tables, from MariaDB 10.0.5 with InnoDB tables and from MariaDB 10.0.15 with Mroonga tables, and can be created only for CHAR, VARCHAR, or TEXT columns. Partitioned tables cannot contain fulltext indexes, even if the storage engine supports them. A FULLTEXT index definition can be given in the CREATE TABLE ... Read More

Feed: Planet PostgreSQL. Welcome to a weekly blog where I get to answer (like, really answer) some of the questions I’ve seen in the webinars I’ve presented lately. If you missed the latest one, PostgreSQL Performance Tuning Secrets, it might be helpful to give some of it a listen before or after you read this post. Each week, I’ll dive deep into one question. Let me know what you think in the comments.  We constantly hear that indexes improve read performance and it’s usually true, but we also know that it will always have an impact on writes. What we ... Read More

Feed: Planet PostgreSQL. Every now and then someone asks me to add index suggestions to explain.depesz.com. I always respond with polite decline. This is complicated thing to do, and I just have that time. Lately I was asked, on Slack to add (to explain.depesz.com) link to pganalyze Index Advisor for Postgres. So I checked it out. And results prompted me to write this blogpost. Before I will go into any details, I need to make sure that you understand: I am not bashing fine people working for pgAnalyze. No. They put in the time, and got some results. But it ... Read More

Feed: Planet PostgreSQL. Originally published at https://blog.yugabyte.com with YugabyteDB in mind, because the benefit of Index Only Scan is huge in a distributed database. It also applies to PostgreSQL, knowing that the hops to the table pages are saved only for the vacuumed part of the table. A distributed SQL database reads from remote nodes, which increases the need for optimal data access. From my 20 years of experience as a database consultant, here is the most overlooked optimization technique for any database that supports it: performance-critical queries should find their columns from the index structure, without making extra hops ... Read More

Feed: Recent Announcements. We’re excited to announce that Amazon Forecast Weather Index is now also available in the Central America, Middle East and Africa regions. Weather Index can increase your forecasting accuracy, by automatically including the latest local weather information in your demand forecasts with one click and at no extra cost. Weather conditions influence consumer demand patterns, product merchandizing decisions, staffing requirements and energy consumption needs – however - acquiring, cleaning, and effectively using live weather information for demand forecasting is challenging and requires ongoing maintenance. With this launch, customers who have been using Weather Index in North America, ... Read More

Feed: R-bloggers. Author: kjytay. What is the Atkinson index? The Atkinson index, introduced by Atkinson (1970) (Reference 1), is a measure of inequality used in economics. Given a population with values and an inequality-aversion parameter , the Atkinson index is defined as If we denote the Hölder mean by then the Atkinson index is simply While the index is defined for all , we restrict to be . (Some of the properties in the next section would not hold otherwise.) Properties of the Atkinson index The Atkinson index has a number of nice properties: The index lies between 0 and ... Read More