About Ilkay
Ilkay has been administering databases including NoSQL and RDBMS for over 7 years. He is experienced working high-scale banking databases. He is currently working at ChistaDATA Inc. as Database Administrator.
Contact: Website

Streaming From Any Source to ClickHouse – Part I

A quick calculation of analytical business data using metrics for modeling, planning, or forecasting is possible with OLAP only. Also a lot of business applications for reporting, simulation models, information-to-knowledge transfers, and trend and performance […]

Simple Bar Feature

ClickHouse has simple bar feature. This enables you to summarize data quickly by creating straightforward charts directly. bar(x, min, max, width) x is the value, min is the 0% and max is the 100% of […]

Utilizing JSON Feature in ClickHouse

ClickHouse offers an experimental JSON format. So we need to SET allow_experimental_object_type = 1 Now, we may use the JSON type and insert JSON values while creating tables. CREATE TABLE exp_test ( `id` UInt64, `value` […]

Performance Tricks in ClickHouse – Part III

Among DBAs, there is much debate regarding the significance of database performance tuning. As we now understand, various data types really power the business world. It should be operating very effectively and always be accessible […]

Memory Limit Exceeded in ClickHouse

Depending on the size of the SELECT or INSERT operation, we can see an error if memory usage is high. Code: 241. DB::Exception: Received from localhost:9000. DB::Exception: Memory limit (for query) exceeded Is there a […]

Performance Comparison of Count Functions

In our previous KB, we mentioned the functions. You can view the tables and data from earlier KBs. We’ll attempt to go through count functions today and compare them. 10.000.000 records were used in this […]

ClickHouse Deduplication Operation

With the help of ClickHouse functions, you can rapidly determine how many duplicate rows are present in a table and then eliminate them, leaving just the unique rows. Let’s create a table: CREATE TABLE default.exp_test […]

How to Diff Two Tables in ClickHouse?

Assume we have two tables with identical amounts of data, each with roughly n million rows for each. If we want to compare the data row by row, we can utilize with sipHash64(*) hash function. […]

Performance Tricks in ClickHouse – Part II

Among DBAs, there is much debate regarding the significance of database performance tuning. As we now understand, various types of data are what really power the business world. It should be operating very effectively and […]

Performance Tricks in ClickHouse – Part I

Among DBAs, there is much debate regarding the significance of database performance tuning. As we now understand, various types of data are what really power the business world. It should be operating very effectively and […]

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