Friday, July 2, 2021

Kusto continued...

 

Kusto is amazingly fast, it is faster than Microsoft SQL Server and it can process billions of records in very little time. It is not a comparable relational database engine. Yet, Azure services are even written on top of Kusto instead of using Microsoft SQL Server. We will see how Kusto is fast but it's also important to note that realizing the characteristics of Kusto will help us do better troubleshooting and writing better queries using Kusto query language

Kusto is fast because it is giving up some features that SQL Server has and  at the same time, it is also leveraging features that SQL Server does not have. For example, SQL Server uses relational data and data constraints but kusto is hardly dealing with read write data. it reads data that is a almost never deleted nor edited. Kusto runs on columnar data so it filters out only those columns that need to be involved in the query with this feature. Kusto is extremely fast and it runs on a cluster with multiple nodes so it can scale arbitrarily

The admin node maintains the metadata store for the cluster. It reads the metadata from blob storage into immutable data structures. The gateway node performs request dispatches and makes and receives api calls. The data hierarchy comprises cluster, database, table, extent data, column and data blocks. The extents are stored on different nodes. A Kusto table has four components: metadata for the table that can be displayed with control commands, an extent directory, a number of extents and column indexes. A Kusto data extent has organization just like a mini table. The extent directory is ordered by ingest time which is why Kusto queries are recommended to have time filters

 

 

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