Shulou(Shulou.com)06/01 Report--

Big data report is too slow to show what to do, I believe that many inexperienced people do not know what to do, so this paper summarizes the causes of the problem and solutions, through this article I hope you can solve this problem.

In order to show more than 1 million data, the report has to be queried by paging. If you write your own code to develop the report, you can realize the paging query. Different databases have different implementation mechanisms, and there are a lot of specific online materials.

If the report is developed with a report tool, it depends on whether the tool itself supports asynchronous paging query. Many report tools provide regular paging (false paging), that is, the data is loaded into memory at once, and then the front end is paged and displayed.

A better way is to use the database paging mechanism to do, using the line number to filter, but this method also has many disadvantages, such as you will find that the back will be slower and slower, and this large list report should be done? Some of the problems mentioned.

There is a better way to follow the ideas given in the above post. The fetch thread and the rendering thread are two asynchronous threads. After sending out the SQL, the fetch thread continuously fetches the data and caches it to the local storage. The rendering thread calculates the number of rows according to the number of pages to the local cache to get the data display. In this way, as long as the data that has been fetched can be presented quickly, there will be no sense of waiting, and it is normal and understandable that the unfetched data needs to wait; while the fetching thread only involves a sentence of SQL, which is the same transaction in the database, and there will be no inconsistency. In this way, both problems can be solved. However, this requires the design of a storage format that can randomly access records by line number, otherwise the records will be counted by traversing, and the response will still be slow.

Draw a picture and feel it:

② and ③ are two threads respectively

It looks a little complicated, so let's use a well-made tool directly: the implementation of massive lists and grouped reports.

You can also export Excel and print.

After reading the above, do you know what to do if big data's report is too slow to show? If you want to learn more skills or want to know more about it, you are welcome to follow the industry information channel, thank you for reading!

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