Problem Statement 1:
Extend this design to support the download for batches stats upto 1L participants. By default elastic search support max 10k records , in one search query.
Use Elastic search scroll api . 'Scroll API ' can be used to retrieve large numbers of results (or even all results) from a single search request, it will work in same way as cursor on a traditional database.
Pros | Cons |
|---|---|
We can retrieve large data set | We can not use scroll api for real time user request |
We can slice the data based upon shards | Performance issues while using it for real time request |
Example:
Path: /{{IndexName}}/{{type}}/_search?scroll=1m
Request Data{
"query": {//Contains the query required to fetch the data
},
"size" : 1000,
}Returns → {"scrollId":"SCROLL ID"hits:["data"]}After receiving the scroll IdWe need to send this request till we get all the resultPath: /_search/scroll{
"scroll": "1m",
"scroll_id":"Scroll id" // received in the previous request}Returns {
"_scroll_id": "Scroll Id",
"hits": {
"total": 263,
"max_score": 0.11207403,
"hits": [ ]
}
}
Approach 1:
We can't start the service instantly or we can generate the batch metrics by running this service once in a day, it should be Async process , and process id need to be track. This process will generate file and upload to some storage and link will be share to user on email. second time we might use same file for particular date range : Ex , if user request for stats for a course batch and for that course batch report is already generated and report validity time not expire then we can re-use it , instead of re-generating.
Important points
It will return the process Id so we can track the status of the process.
if multiple user try to create stats for same batch we can check if any process exists in the system for same batch id and the duration is less than a day, we can send already created file to the requested user, else we can trigger the process to get the latest data and store the file path in the process.
We have to maintain the list of user who triggered the request so that we can send a mail to all the requested user.
Problem Statement 2:
Extend this design to support the batches stats page upto 1L participants. By default elastic search support max 10k records , in one search query.
Solution 1:
Using relation database management system. RDBMS provide both pagination and sorting available.
Pros | Cons |
|---|---|
We can handle large data set | We have to manage a new DB |
Syncing data will be an issue |
Solution 2:
Using filter inside the current implementation as reading more than 10 thousand records is not feasible by user
Pros | Cons |
|---|---|
We just need to handle the extra query parameters | If after adding search filters, more than 10000 results, user will not be able to read the data |