Questions tagged [database-optimization]
186 questions
-1
votes
1 answer
Why are Many-to-Many joins so resource-consuming and how to predict requirements vs performance
In a traditional RDBMS,
why are Many-to-Many Joins so much more resource consuming than Many-to-One joins?
After all, aren't Many-to-Many relationships just like two Many-to-One relationships?
I am observing Many-to-Many queries getting slow past…
user1767316
- 2,438
- 3
- 26
- 41
-1
votes
2 answers
spoeding up a "distinct" select with LIMIT x in postgres
The following query is very slow :
select distinct gene_symbol from my_table where gene_symbol like 'ED%' limit 15
which is not surprising, since the distinct causes it to do a hash aggregate.
This version runs a lot faster :
with q0 as (
…
Max L.
- 8,994
- 12
- 49
- 80
-1
votes
1 answer
Need Help for Optimizing MySQL query with few joins
Hello I have the follow sql query it works but it is kind of slow
SELECT
ep . *,
t_u.sUsername AS sLockedBy,
epi.sName,
em.sName AS sManufacturerName,
SUM(IF(eop.dInProduction IS NULL
AND eop.dFromProduction IS…
Dimitar Kudev
- 3
- 3
-1
votes
2 answers
How mysql/innodb database size impacts performance?
I have a 30 GB large mysql database where all tables use innodb engine.
Almost all of this space is taken by one large table (about 25 GB) where I store large texts in binary format, but 99% of the queries use other, smaller, tables.
My server has…
Silver Light
- 37,827
- 29
- 116
- 159
-2
votes
2 answers
MySql Query Timed Out in Live but not in Local
We are using MySQL InnoDB.
We have a query looks like this.
In our live environment, this query took more than 30 seconds to complete.
select count(*) as aggregate
from `parents`
where exists (
SELECT *
from …
Gab
- 1
- 2
-2
votes
2 answers
MYSQL database optimization using indexing
I am working on LearnBiz Simulations, a self-funded start-up which makes simulations for the domain of management education.
(a) Our website is currently catering to about 16k people. Currently, size of database is 30 mb with a total of about 90…
rajankaneria
- 193
- 1
- 1
- 6