## Where is Count-Min Sketch used?

Count-min sketch is used to count the frequency of the events on the streaming data. Like Bloom filter, Count-min sketch algorithm also works with hash codes. It uses multiple hash functions to map these frequencies on to the matrix (Consider sketch here a two dimensional array or matrix).

**Why do we need Count-Min Sketch?**

Summary. To summarize, the Count-Min Sketch is a probabilistic data structure for computing approximate counts. It is useful whenever space requirements could be problematic and exact results are not needed. The data structure is designed in a way that allows freely trading off accuracy and space requirements.

### Do count-min sketches provide error guarantees relative to the answer?

The Count sketch (Charikar, Chen and Farach-Colton) provides guarantees relative to the L2 norm of the data frequencies, while the CM sketch gives guarantees relative to the L1 norm, at the expense of a worse dependence on epsilon (1/epsilon^2 instead of 1/epsilon).

**How do you find the minimum count in SQL?**

To find the minimum value of a column, use the MIN() aggregate function; it takes the name of the column or expression to find the minimum value. In our example, the subquery returns the minimum value in the temperature column (subquery: SELECT MIN(temperature) FROM weather ).

## What is probabilistic data structure?

Probabilistic data structures are a group of data structures that are extremely useful for big data and streaming applications. Generally speaking, these data structures use hash functions to randomize and compactly represent a set of items.

**What are sketching algorithms?**

Sketching algorithms simplify the computational task by generating a compressed version of the original dataset that then serves as a surrogate for calculations. The compressed dataset is referred to as a sketch, because it acts as a compact representation of the full dataset.

### What is FM algorithm in big data?

Flajolet Martin Algorithm, also known as FM algorithm, is used to approximate the number of unique elements in a data stream or database in one pass. The highlight of this algorithm is that it uses less memory space while executing.

**How do Bloom filters work?**

A Bloom filter is a data structure designed to tell you, rapidly and memory-efficiently, whether an element is present in a set. The price paid for this efficiency is that a Bloom filter is a probabilistic data structure: it tells us that the element either definitely is not in the set or may be in the set.

## How do you find the minimum value of a column?

If the cells are in a contiguous row or column

- Select a cell below or to the right of the numbers for which you want to find the smallest number.
- On the Home tab, in the Editing group, click the arrow next to AutoSum. , click Min (calculates the smallest) or Max (calculates the largest), and then press ENTER.