# OLTP Vs OLAP

![`smart`](OLTPOLAP_aa_002_20220512.png)

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The demand for HTAP databases is rising for a reason. Compared to the traditional combination of OLTP and OLAP business scenarios, HTAP has many advantages. 

The database on the leftmost of the figure is the OLTP business database, which supports row storage. After the data is written into the OLTP business database, it will be extracted by the ETL component to the OLAP database (data warehouse or data lake) to support the analysis business. Afterwards, the data may be extracted back from the OLAP database to the OLTP business database or other business scenarios such as data mart, which will not be expanded here.

It is not difficult to understand that there are two problems with traditional solutions: 
1. The extraction of ETL has considerable latency, which cannot achieve fact analysis, such as T+1, T+2, etc.; 
2. Data exists in multiple copies, and maintenance becomes more and more difficult.