database-performance Questions
1
Solved
I am facing some very weird issue here. We have a laravel API hosted on AWS EC2 and we using RDS (mysql 5.6). I recently enabled performance_schema on RDS. Following is the behavior I am noticing
...
Cogitate asked 8/4, 2018 at 4:20
1
Implementing an Android+Firebase app, which has a many-to-many relationship: User <-> Widget (Widgets can be shared to multiple users).
Considerations:
List all the Widgets that a User has.
A...
Garwood asked 14/3, 2016 at 19:57
9
Solved
I've noticed that a lot of folks here cite tables with 20+ (I've seen as much as 55) columns in one table. Now I don't pretend to be a database design expert, but I've always heard that this ...
Outing asked 6/7, 2010 at 8:0
1
Solved
I have a postgres table (lets call this table Events) with a composite foreign key to another table (lets call this table Logs). The Events table looks like this:
CREATE TABLE Events (
ColPrimary...
Gothurd asked 14/2, 2018 at 17:32
1
Solved
I am trying to find out if a document exists or not on my database, and I am kind of curious, what is the best way to do this?
Using
User.findOne(query).select('_id')
or
User.count(query)
On on...
Blakley asked 6/2, 2018 at 18:21
5
Solved
I could see the DBA team advises to set the sequence cache to a higher value at the time of performance optimization. To increase the value from 20 to 1000 or 5000.The oracle docs, says the the cac...
Maddeu asked 19/6, 2014 at 4:35
2
Solved
I read this answer from Marc Gravell (@MarcGravell): https://stackoverflow.com/a/47790712/5779732
The last line says:
As a minor optimization to your code: prefer AsList() to ToList() to avoid ...
Unfeeling asked 13/12, 2017 at 13:38
7
Current situation in SQL Server database
There is a table Entry with the following columns:
EntryID (int)
EntryName (nvarchar)
EntrySize (int)
EntryDate (datetime)
Further there should be the ...
Rue asked 5/9, 2013 at 7:38
3
Solved
For a few days, I've been struggling with improving the performance of my database and there are some issues that I'm still kind a confused about regarding indexing in a SQL Server database.
I'll ...
Quaff asked 16/10, 2017 at 9:16
2
Solved
I need to do fast queries to find all documents within a certain GPS radius of a point. The radius will be small and accuracy is not that critical, so I don't need to account for the spherical geom...
Nellynelms asked 20/1, 2014 at 22:28
1
Solved
I notice that some databases like Postgres add Enum but the question is,
At what point integer/string based enum becomes a performance issue?
Following this answer about differences Postgresql en...
Trumpetweed asked 5/7, 2017 at 4:55
2
I have a laravel application which must insert/update thousands of records per second in a for loop. my problem is that my Database insert/update rate is 100-150 writes per second . I have increase...
Norsworthy asked 14/6, 2017 at 18:58
2
How can I efficiently search json data in a mysql database?
I installed the extract_json udf from labs.mysql.com and played around with a test table with 2.750.000 entries.
CREATE TABLE `testdb`....
Flexor asked 31/10, 2014 at 8:10
2
Solved
Suppose a SQL database of "values of series". Each Value belongs to a Series, and has a date:
@Entity
class Series { … }
Value {
Series series;
Date date;
…
}
Each value is unique for each ...
Vinegarroon asked 26/6, 2017 at 19:50
1
I have a complex query which uses a lot of binary checksum function, when I was testing it with some test data for two distinct records it actually returned me same checksum value. Please find the ...
Bennir asked 3/4, 2017 at 11:20
2
Solved
I am really struggling to optimize this query:
SELECT wins / (wins + COUNT(loosers.match_id) + 0.) winrate, wins + COUNT(loosers.match_id) matches, winners.winning_champion_one_id, winners.winning...
Otey asked 15/4, 2017 at 7:34
1
Solved
Given the following in a SQL Server 2014 DB:
create table t
(
c1 int primary key,
c2 datetime2(7),
c3 nvarchar(20),
c4 as cast(dbo.toTimeZone(c2, c3, 'UTC') as date) persisted
);
create inde...
Deandra asked 16/3, 2017 at 6:36
3
Solved
My question comes directly from this one, although I'm only interested on UPDATE and only that.
I have an application written in C/C++ which makes heavy use of SQLite, mostly SELECT/UPDATE, on a v...
Aficionado asked 3/2, 2017 at 18:30
1
I use Hibernate Envers 4.3.10.Final.
I have the following two JPA-classes:
public class Factory {
private int factoryID;
....
}
public class Trgs{
private int trgsID;
@ManyToOne(fetch=Fet...
Importation asked 24/4, 2016 at 6:51
3
Solved
I'm storing UUID v4 values in a PostgreSQL v9.4 table, under column "id".
When I create the table, is there any difference in following write or read performance whether I define the "id" column a...
Giuliana asked 24/8, 2015 at 18:23
5
Solved
I have a long running process in C# that hits a Sql table anywhere from 10 to 200 times. When the process exceeds about 50 hits and queries greater than about 100,000 rows from the same table each ...
Kamakura asked 20/9, 2015 at 15:33
2
Possible explanation is here in the comment
In SQL Server 2014 Enterprise Edition (64-bit) - I am trying to read from a View. A standard query contains just an ORDER BYand OFFSET-FETCH clause l...
Splint asked 24/8, 2016 at 10:59
3
Solved
I'm building a simple android RPG. Each player has access to a maximum of about 50 soldiers. Each soldier has some stats (class, hp, attack, etc), and three inventory slots. There will be onl...
Herschelherself asked 3/2, 2015 at 14:34
3
Solved
I have a composite unique index across 4 columns in my table and a query with performance problems that filters on 2 of the columns individually.
Perhaps a dumb question, but should I index the ind...
Tavares asked 20/9, 2016 at 18:50
5
Solved
summary: I've seen a lot of advice against using SELECT * in MS SQL, due to both performance and maintainability concerns. however, many of these posts are very old - 5 to 10 years! it seems, from ...
Tungstic asked 2/9, 2016 at 15:29
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