database-performance Questions
5
Solved
In a discussion with a friend, I got to hear two things -
Using constraints causes slight decrease in performance. eg. Consider a uniqueness constraint. Before insertion, DBMS would have to chec...
Pameliapamelina asked 1/10, 2016 at 7:21
15
Solved
At what point does a MySQL database start to lose performance?
Does physical database size matter?
Do number of records matter?
Is any performance degradation linear or exponential?
I have what...
Icbm asked 4/8, 2008 at 14:31
5
Solved
At work we've been hacking away at a stored procedure and we noticed something.
For one of our update statements, we noticed that if the values are the same as the previous values we had a perform...
Pallua asked 3/2, 2012 at 15:50
1
So I have a small and simple Redis database. It contains 136689 keys whose values are hash maps containing 27 fields. I'm accessing the table through the Python interface on the server node, and ne...
Ricoricochet asked 31/10, 2019 at 22:11
3
I am doing a PoC to check if Postgres is the right candidate for our use cases.
I have the following workload:
Data query:
Presentation layer will retrieve data every 15 mins for last 2 weeks
Da...
Neuman asked 11/8, 2017 at 7:51
3
Solved
Hi i have this large oracle hibernate web applications and it seems to give this error
ORA-01795: maximum number of expressions in a list is 1000
and i need a java code tested by someone as a hi...
Constance asked 14/2, 2013 at 6:33
4
Solved
I have a million row table in Oracle 11g Express and want to run a slow SQL select query so I can test stopping agents in various ways and observe the results on the database server.
However no m...
Bandeau asked 14/4, 2014 at 22:51
5
Solved
I have MySQL 5.5.37 with InnoDB installed locally with apt-get on Ubuntu 13.10. My machine is i7-3770 + 32Gb memory + SSD hard drive on my desktop. For a table "mytable" which contains only 1.5 mil...
Foxhound asked 9/7, 2014 at 17:44
3
Solved
How does the performance of the following two query components compare?
LOWER LIKE
... LOWER(description) LIKE '%abcde%' ...
iLIKE
... description iLIKE '%abcde%' ...
Aerobiosis asked 2/12, 2013 at 19:55
1
Solved
I've got this query, which I'll simplify for brevity:
public IQueryable<User> GetByIdAsync(Guid userId)
{
return MyContext
.Users
//Bunch of Includes
//Most of which have a ThenInclude
...
Handpick asked 25/8, 2019 at 5:28
5
Solved
I was working on task about optimization queries. One of the improvement ways was using WITH clause. I notice that it did very good job, and it lead to shorter time of execution, but i am not sure ...
Coset asked 22/8, 2019 at 13:41
1
Solved
I face a problem which connected with MongoDb performance. Queries are tens of seconds and by means of command db.currentOp() I can see, that all my queries are waiting database lock. For example:
...
Lozenge asked 23/6, 2016 at 7:43
3
Solved
Background
I have a MySQL test environment with a table which contains over 200 million rows. On this table have to execute two types of queries;
Do certain rows exists.
Given a client_id and a...
Congress asked 13/6, 2019 at 8:21
3
Solved
Our cosmos db aggregate query seems slow and costs a lot of RUs. Here are the details (plus see screenshot below): 2.4s and 3222RUs to count a result set of 414k records. Also this for just one cou...
Smaze asked 1/5, 2019 at 1:22
4
It appears that SQL Server does not automatically use a CHECKSUM/hash index unless the CHECKSUM column is explicitly included in the search arguments for the query. This is a problem because I do n...
Atrocity asked 18/6, 2012 at 13:38
1
Solved
Using postgres 9.6.11, I have a schema like:
owner:
id: BIGINT (PK)
dog_id: BIGINT NOT NULL (FK)
cat_id: BIGINT NULL (FK)
index DOG_ID_IDX (dog_id)
index CAT_ID_IDX (cat_id)
animal:
id: BIGIN...
Slavish asked 23/4, 2019 at 17:11
1
Solved
I'm experiencing an issue similar to PostgreSQL query very slow with limit 1 and Extremely slow PostgreSQL query with ORDER and LIMIT clauses although in my case it doesn't matter if the LIMIT is 1...
Wedged asked 25/3, 2019 at 18:48
1
Solved
I've been reading through the WAL chapter of the Postgres manual and was confused by a portion of the chapter:
Using WAL results in a significantly reduced number of disk writes, because only th...
Jacie asked 25/3, 2019 at 15:40
1
Solved
I'm about upgrade a quite large PostgreSQL cluster from 9.3 to 11.
The upgrade
The cluster is approximately 1,2Tb in size. The database has a disk system consisting of a fast HW RAID 10 array of ...
Burial asked 4/12, 2018 at 18:0
4
Solved
I just recently upgraded to MySQL 5.1.6 in order to take advantage of the ability to save the general log to a table -> i.e. mysql.general_log. Once i did this I was immediately surprised how many ...
Reservation asked 18/2, 2012 at 16:41
8
I use Talend to load data into a sql-server database.
It appears that the weakest point of my job is not the dataprocessing, but the effective load in my database, which is not faster than 17 rows...
Lacee asked 14/4, 2014 at 15:30
5
Is there a faster way to update the oldest row of a MySQL table that matches a certain condition than using ORDER BY id LIMIT 1 as in the following query?
UPDATE mytable SET field1 = '1' WHERE fie...
Determiner asked 8/9, 2010 at 11:27
1
All the MySQL tables in my PHP web application are MyISAM with utf8 encoding. Since records can be generated from a companion app while it's offline, my table keys are randomly generated, alphanume...
Orthodontics asked 14/6, 2018 at 4:34
0
I have a Firebase database that clients access via a REST API run on node.js, which then reads from my firebase database using the firebase-admin node client. For most of my endpoints, several conc...
Dani asked 31/5, 2018 at 0:22
4
Solved
We're using Postgresql 9.1.4 as our db server. I've been trying to speed up my test suite so I've stared profiling the db a bit to see exactly what's going on. We are using database_cleaner to trun...
Fitz asked 10/7, 2012 at 18:25
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