R-Tree and Quadtree Comparison

Here’s paper which has pretty nice comparison of QuadTrees and R Trees: Quadtree and R-tree Indexes in Oracle Spatial: A Comparison using GIS Data Some differences: Quadtrees require fine-tuning by choosing appropriate tiling level in order to optimize performance. No specific tuning is required for R-Trees. Quadtree can be implemented on top of existing B-tree. … Read more

Index in Parquet

Update Dec/2018: Parquet Format version 2.5 added column indexes. https://github.com/apache/parquet-format/blob/master/CHANGES.md#version-250 See https://issues.apache.org/jira/browse/PARQUET-1201 for list of sub-tasks for that new feature. Notice that this feature just got merged into Parquet format itself, it will take some time for different backends (Spark, Hive, Impala etc) to start supporting it. This new feature is called Column Indexes. Basically … Read more

Proper terminology, should I say indexes or indices? [closed]

“Indices” is the mathematical formulation whereas in publishing they use “indexes” (which is probably why so many people in IT consider “indices” to be more correct than “indexes”). I think that a table index is analogous to an index in a book rather than an exponent in maths, so the publishing variant is the appropriate … Read more

Solr commit and optimize questions

A little more detail on Commit/Optimize: Commit: When you are indexing documents to solr none of the changes you are making will appear until you run the commit command. So timing when to run the commit command really depends on the speed at which you want the changes to appear on your site through the … Read more

Create or update mapping in elasticsearch

Generally speaking, you can update your index mapping using the put mapping api (reference here) : curl -XPUT ‘http://localhost:9200/advert_index/_mapping/advert_type’ -d ‘ { “advert_type” : { “properties” : { //your new mapping properties } } } ‘ It’s especially useful for adding new fields. However, in your case, you will try to change the location type, … Read more