Optimise multiple queries in viewall students

[icyflame]

https://github.com/icyflame/erp-rails/blob/master/app/views/viewall/students.html.erb#L28

@aniarya82
In this module, you are sending a query for each alumni ID. This is a very very network intensive operation. You should not calculate the count this way. You should calculate the count using the count feature in ActiveRecord. Fix this on an urgent basis.

[icyflame]

@aniarya82
Solution

1. maintain a counter for each student per response and per search (10 counter's total, Hash preferably)
2. fetch all the alumni status records <- total queries = 1
3. fetch all the tie records <- total queries = 2
4. now, for each tie record :-

• check the appropriate alumni status record (and increment the appropriate student's count)

This will solve the above problem in just 2 queries, as compared to the 2n queries you were using before. (n being the number of alumni in the DB)

[aniarya82]

yeah i figured this as the only way out.

Anyways working on it..

All four issues expected to close by tomorrow.

On Fri, Jun 12, 2015 at 11:47 PM, Siddharth Kannan <[email protected]

wrote:

@aniarya82 https://github.com/aniarya82
Solution

1. maintain a counter for each student per response and per search (10
   counter's total, Hash preferably)
2. fetch all the alumni status records <- total queries = 1
3. fetch all the tie records <- total queries = 2
4. now, for each tie record :-

• check the appropriate alumni status record (and increment the
  appropriate student's count)

This will solve the above problem in just 2 queries, as compared to the 2n
queries you were using before. (n being the number of alumni in the DB)

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#52 (comment).

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Hiten Chowdhary

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Department of Mathematics

IIT Kharagpur

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[icyflame]

@aniarya82
Sure!

[icyflame]

@aniarya82

The last PR #63 did not have any effect on the query scenario of the application. You need to spend some more time to close this out. (I have merged it because it improved the front end quite a bit)