Denys Golotiuk – Medium

Denys Golotiuk

Denys Golotiuk
in
DataDenys

Using partitions in Clickhouse

Clickhouse supports table partitioning which can be useful in cases we deal with serial data and need to work only with a moving window of…

Nov 29, 2022

Using partitions in Clickhouse

Nov 29, 2022

Denys Golotiuk
in
DataDenys

Estimating duplicates and deduplicating data in Clickhouse

Clickhouse has a way to quickly estimate number of duplicates in a table as well as remove duplicates so only unique rows remain. Popular…

Nov 21, 2022

Estimating duplicates and deduplicating data in Clickhouse

Nov 21, 2022

Denys Golotiuk
in
DataDenys

How to use window functions in Mysql

Using windows in Mysql is a way to query data based on a set of rows instead of a single row. This helps in comparative analysis, when we…

Nov 11, 2022

How to use window functions in Mysql

Nov 11, 2022

Denys Golotiuk
in
DataDenys

Big data exploratory data analysis with Clickhouse

Any analysis starts with exploratory stage — when we try to understand the big picture of the data itself. We usually do things like…

Nov 4, 2022

Big data exploratory data analysis with Clickhouse

Nov 4, 2022

Denys Golotiuk
in
DataDenys

Data cleansing and preparation for analysis with Python and Pandas

Any data usually (always?) contain errors. In order to do accurate analysis and build efficient ML models, data needs to be cleansed prior…

Nov 2, 2022

Data cleansing and preparation for analysis with Python and Pandas

Nov 2, 2022

Denys Golotiuk
in
DataDenys

Optimizing star-schema queries with IN queries and denormalization

Most data environments usually have 2 main groups of data objects. First — event based objects, usually organized into timeseries tables…

Oct 31, 2022

Optimizing star-schema queries with IN queries and denormalization

Oct 31, 2022

Denys Golotiuk
in
DataDenys

Using projections to speedup queries in Clickhouse

Clickhouse is efficient enough so most analytical queries will execute fast in many cases without extra optimization activities. But, if…

Oct 28, 2022

Using projections to speedup queries in Clickhouse

Oct 28, 2022

Denys Golotiuk
in
DataDenys

Working with JSON in Clickhouse

There’s plenty of cases when we can’t define data structure in advance due to its dynamic nature. Data objects can have different set of…

Oct 26, 2022

Working with JSON in Clickhouse

Oct 26, 2022

Denys Golotiuk
in
DataDenys

Solving systems of linear equations using matrices and Python

Matrices stay at the very basis of all math used for ML. Let’s understand why it is so and how matrices can be used to solve systems of…

Oct 19, 2022

Solving systems of linear equations using matrices and Python

Oct 19, 2022

Denys Golotiuk
in
DataDenys

Using EXPLAIN in Mysql to analyze and improve query performance

Mysql EXPLAIN statement lets us understand efficiency of our queries and grasp ideas on possible ways to optimize it. Just creating indexes…

Oct 17, 2022

Using EXPLAIN in Mysql to analyze and improve query performance

Oct 17, 2022

Denys Golotiuk

Denys Golotiuk

I write about data, machine learning, and its practical implementation. github.com/mrcrypster https://datachild.net golotyuk@gmail.com

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