I have a compound index on 3 columns. Now I want to execute the query based on only 2 columns, which both are not indexed. So the query takes long time to execute. How to I make use of the…
I have a search function which works with a small amount of data, but after I filled the database with ten thousands of data, the site gets stuck on loading when I try to search for something. pubblic function searchVideo(Request…
SELECT * FROM `users` WHERE `id` != 1 AND `users`.`activated` = 1 AND NOT EXISTS ( SELECT 1 FROM `blockings` WHERE (blockings.user_id = users.id AND blockings.blocked_id = 1) OR(blockings.blocked_id = users.id AND blockings.user_id = 1)) ORDER BY users.id DESC LIMIT…
I am using using MySQL (InnoDB engine). I am running SQL query with WHERE IN statement which is also ordered. I decided to create the perfect index, so my query will not run slow. Surprisingly, after creating the perfect index…
I'm working on a project with a MySQL database. I have some CTEs that summarize features of the users (each CTE summarizes one feature). Then I have a last query that joins all other CTEs on a column named user_id.…
Consider an example table of items with three columns: id (UUID, primary key) time (TIMESTAMPTZ) store_id (UUID, foreign key) There is a covering B-tree index on (store_id, time) INCLUDING (id). Finding the top-N items I'd like to write a query…
I am developing a chatting application. I have written a SQL to get the active chats associated with the user. It used to get user to user chat and group chats based on sort it in descending order based on…
Postgres behaves radically differently on parameters that don't change the result. -- This query is fast (~ 40 ms) WITH filtered_scans AS ( SELECT id FROM scans WHERE scans."createdAt" BETWEEN NOW() - INTERVAL '26 day' AND NOW() AND scans."applicationId" =…
id Plot_name Measurement firmware_revision 1 InboundTraffic1Byte 300 1.5 2 InboundTraffic500Bytes 200 1.5 3 InboundTraffic1000Bytes 100 1.5 4 InboundTraffic1Byte 1.6 5 InboundTraffic500Bytes 200 1.6 6 InboundTraffic1000Bytes 100 1.6 A MySQL database stores measurements from performance tests, and there is a Grafana…
minimize sum(j in tavail) 0.2*(ptn[j]*1000000-pln[j]1000000+sum(k in nport)pevch[j][k]- sum(k in nport)(DOD1[k][j]-dod[k][j])cap[k][j]1000) +0.8(sum(j in tavail)(-sum(k in nport)(-32768DOD1[k][j]+49546)(DOD1[k][j]-dod[k][j])*cap[k][j]*1000); This is the mentioned objective function. Here the weight taken is 0.2 and 0.8. With change in weightage values only objective function value is changing.…