0
votes
3answers
44 views

Performance first low, then high after adding index, then keep high after drop index

I am testing performance a complicated select query. It is very slow. using explain, I have found a ALL in type COLUMN. Then I ADD INDEX. result comes out fast. However, when I DROP the INDEX I ...
2
votes
2answers
72 views

I need help optimizing a not that complicated query that returns unexpedcted performance problems

I have a table that stores details about incoming and outgoing phone calls such as when a call was made, or when a call was received, the phone number of the caller, and the phone number of the ...
0
votes
1answer
118 views

MySQL pivot table via a view

Suppose the following schema CREATE TABLE `log_apache` ( `date` datetime NOT NULL, `count` int(10) unsigned NOT NULL, `input` bigint(20) unsigned NOT NULL, `output` bigint(20) unsigned NOT ...
2
votes
1answer
84 views

Update old database with SQL dump

I had to recover a database with a some months old full backup. I have however in my possession a most recent but unfortunately incomplete SQL dump for this same database done with mysqldump. Is ...
1
vote
2answers
330 views

Slow query responce on different mysql versions, percona, MariaDB

LEFT JOIN is supposed to be faster than a NOT IN query. This is what I've read online. But practically, this seems to be opposite. I have the following query here, INSERT IGNORE INTO callrequests ...
2
votes
3answers
391 views

How can I improve my table design for different types of an entity?

Consider an accounting system as an example. I have an Entity called Client. Client can be of different types, with different fields applicable to different types. I consider creating separate tables ...
0
votes
0answers
364 views

Oracle Flashback Archive aka Total Recall in MySQL

What would you suggest as a replacement system to achieve the same functionality of Oracle Flashback Archive aka Total Recall in other DBMS, in general or specifically in MySQL or MariaDB? ...
6
votes
2answers
2k views

How can I improve my SQL statement with weekly results with week starting on Thursday or any other day of the week?

I am a total newb, and I couldn't find a good way to do this anywhere. I have a database table that contains statistics that are recorded at various time throughout the week. The reporting week ...