An evaluation of whether a system works well enough to be fit for purpose. Normally performance refers to the speed with which a system completes an operation or set of operations over time.

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3
votes
3answers
108 views

Nested table hierarchy: foreign key duplication vs. join

I have a nested table hierarchy, similar to the following one (this is an example but demonstrates the schema well enough): +---------+ +---------+ +---------+ +-------------+ | users | | ...
0
votes
1answer
16 views

Mysql Inner join performance

I have performance problem! I searched for Inner Join, tried optimize table but still the same. I have Users, Entries, Tags and tag_user tables. This code works perfectly : select * from `entries` ...
0
votes
1answer
142 views

Query running slow on script and producing error 500 when run in phpmyadmin

I have a query that seems to take a good 30 seconds to execute even when the query produces no results. There are 4000 lines within the database and queries that produce all results run within ...
1
vote
0answers
16 views

What might be the cause of regular periodic slow transactions on an OLTP system?

I have a two node Oracle RAC cluster with that runs an oltp application against it. I have both a production and a duplicate test environment with the same setup. Upon running stress tests on the ...
6
votes
1answer
12k views

Optimizing large database query (25+ million rows, using max() and GROUP BY)

I'm using Postgres 9.3.5 and I have a large table in the database, currently it has over 25 million rows and it tends to get even larger rapidly. I'm trying to select specific rows (all unit_ids with ...
19
votes
2answers
12k views

Configuring PostgreSQL for read performance

Our system write a lots of data (kind of Big Data system). The write performance is good enough for our needs but the read performance is really too slow. The primary key (constraint) structure is ...
2
votes
1answer
218 views

CPU Time Slower in SQL Server 2014 than in SQL Server 2008

We’re upgrading a virtualized database server from an old SQL Server 2008 R2 Standard (vmware) to a new shiny SQL Server 2014 Standard server (hyper-v). We were doing some performance testing and to ...
1
vote
1answer
22 views

How to Create Indexes Or Manage Performance For Complex Queries Before a Release?

Last night we had a major release that involved a massive data dump and some complex queries. We semi-anticipated the slowness and were able to react quickly to creating some new indexes in SQL ...
3
votes
3answers
947 views

How much RAM should SQL Server have [duplicate]

I have a database which takes up 500gb, I have noticed that my ple is low even though I have 100gb of RAM. I have searched in google to find reasons of that and I found some interesting queries. I ...
1
vote
1answer
73 views

Primary Index VS Unique Index Performance

I have the following table: CREATE TABLE `actions` ( `user_id_from` int(11) unsigned NOT NULL, `user_id_to` int(11) unsigned NOT NULL, `action_type` int(11) NOT NULL, `counter` smallint(11) ...
0
votes
1answer
190 views

Application is hanging when database upgraded from SQL Server 2000 to SQL Server 2008 R2

Presently we are working with SQL Server 2000, the database is perfectly working with our software for retail sales counter application developed with VB 6.0. But after upgraded to SQL Server 2008 R2, ...
0
votes
0answers
22 views

Increase in IO and CPU cost when explicit conversion is used in a query

I want to check the notable difference between the IO and CPU cost when explicit conversions like Convert or Cast are performed and when not as we need to take a call whether to use or not explicit ...
0
votes
0answers
21 views

MySQL “stalling” when database grows in size

Having a problem where lots of queries timeout. From innodb engine output it looks like lots of queries are blocked? --Thread 139681112069888 has waited at btr0cur.c line 523 for 0.00 seconds the ...
7
votes
4answers
10k views

Slow query on large table with GROUP BY and ORDER BY

I have a table with 7.2 million tuples which looks like this: table public.methods column | type | attributes --------+-----------...
-1
votes
1answer
44 views

Most efficient way to log user login IPs

I am looking for ideas on how to log user's login IPs without compromising on performance in MySQL. There are few primary tasks which the log would be used for: Finding list of other users who have ...
3
votes
1answer
660 views

Select * from statement execute very slowly, innodb io read speed is low

I have a very simple query " select * from ap_statistic " running in my servers. the servers have the same hardware and software configuration (CPU 8 core, mem :32G, OS: redhat 5.5, mysql version: 5....
2
votes
3answers
825 views

Oracle Compatible Parameter to set

Is there any difference in setting the Compatible Parameter to 11.2.0.0 vs 11.2.0.4 ? Are there any advantages / dis-advantages ?
0
votes
1answer
420 views

MySQL Config for server with 8gb RAM and 4 cpus

I have a server with 8gb ram and 4 cpus. I don't have enough time for testing and bench marking so I would like to get the advise of experts like you guys, let me know if something is wrong with my ...
0
votes
1answer
118 views

MongoDB Tag-Aware Sharding Workflow

I wonder the work flow of sharding cluster in Tag-Aware Sharding. --- Sharding Status --- sharding version: { "_id" : 1, "version" : 3, "minCompatibleVersion" : 3, "currentVersion" ...
2
votes
1answer
59 views

SQL Server Express 2016 high CPU Usage as soon as I log into Windows

I have a Windows Server 2012 R2 configured for ASP.net applications that connect to SQL Server 2016 Express installed on the server. This server is a VPS with 3 cores and 1.5 GB RAM. The load on the ...
1
vote
1answer
64 views

Optimize mysql database performance

I have a database with some relatively small tables and one big table with about 10 million rows (11 columns) that I would like to optimize its performance. The table looks like this: Id: (int 11, ...
1
vote
1answer
16 views

Does Couchbase/CouchDB allow me to move / skip the CRUD middle man from the server?

So currently this is a common setup: Client -> Ajax -> Server CRUD -> Database Does Couchbase allow me to do this? Client -> Ajax -> Database This might be more technically correct: ...
0
votes
1answer
145 views

Slow mysql query full text search tag database

In the database are ~700k images. Each image has its own tag(s). I want to be able to search images by the tags with a full text search query. The query does exactly what I want but it's very slow. ...
0
votes
0answers
27 views

Data Base Error

I have an online game. The game server every 2 hrs lost connection with data base & when i check the gameserver log i found this 2016-7-18 2:1:8 -- ERROR: Database ExecuteSQL(MySQL client run out ...
0
votes
2answers
255 views

Please recommend changes for my.cnf

I am not having any performance problems per se but want to improve my sites' performance if possible. Would appreciate any advice for how I can improve my.cnf. I have just one server, not ...
3
votes
1answer
46 views

Online text based game design - Am I linking the databases correctly?

I'm trying to recreate an old game that I used to play that went offline quite some time ago. I'm doing this as a hobby project for myself with the hope that maybe a few hundred people might enjoy it ...
0
votes
2answers
17 views

Open Source tools to visualise MySQL/MariaDB performance metrics (show global status with intervall)

I search for an Open Source tool to visualise MySQL/MariaDB performance metrics (output of show global status in nice graphs). In MongoDB world there is the Closed Source Ops Manager and the Open ...
0
votes
1answer
264 views

How to track IOPS statistics?

Is there a way to access statistics about IO operations per second in DB2 9.7? I am not interested in the buffer pool hit ratio, just IOPS.
0
votes
1answer
117 views

Slow ranking values in MySQL

I have a table of around 30 million retail products, with various INT columns that describe sales counters and pricing at different retailers. I'm supposed to display well over 70 different rankings ...
2
votes
3answers
178 views

SOS_Scheduler_Yield wait type

I am having a process that has a last_wait_type as SOS_Scheduler_Yield and is inserting 100 records to a table. This process has been with this wait type forever with low CPU utilization %. There are ...
12
votes
2answers
245 views

How to track blocking that happen for less than a second - SQL Server

I am trying to troubleshoot a blocking issue which happens for less than a second. The OLTP application is very sensitive and has to have an response time of less than 200ms for some transactions as ...
2
votes
2answers
2k views

Improve MySQL Query Performance - Too many records

I am using MySQL RDMS for a contact management system. Now a days my database grew in size and contains more than 1 million records. Checking duplicate phone numbers became a big issue during ...
6
votes
1answer
434 views

MS SQL high tempdb disk I/O during merge replication of BLOBs

Having a merge publication for replicating BLOBs (sql type - image), got very high tempdb disk I/O for my size of data. Publication is download-only and has no filters. High disk I/O is caused by ...
2
votes
1answer
563 views

Database design for a table with both bulk insert and single row insert

I have to design a table where records will be inserted in two ways. Bulk insert from a batch process from a delimited text file between 2 - 3 million rows in a short burst. Later the same records ...
3
votes
2answers
55 views

Does it make sense to store a couple of Boolean values as array?

I have a table with five Boolean columns. In 90% plus of the rows, all the columns are null. (False is equivalent to null for me.) Instead of having Boolean columns, I could have a single array ...
1
vote
4answers
250 views

mysql need help optimizing query

I have a table containing servers logs, and another table containing rules to match certain and drop them. The logs tables contains around 1 million rows, and there are about 20-30 rules. The ...
0
votes
0answers
11 views

Using DMVs with Database Tuning Advisor

DMVs / DMFs are supposed to be used now instead of SQL Server Profiler because of resource hogging of Profiler, right? In that case, could someone point me in the direction of a good article / ...
0
votes
1answer
29 views

PHPMyAdmin very slow inserts

I was trying to insert around 70K records to mysql database through phpmyadmin and was shocked of how slow it is. It took around 5 hours to complete! Please find below the details of the table/...
0
votes
0answers
17 views

Do I need to index JOINED columns even if they only appear in SELECT?

This is a reformatting of the question asked here: MySQL JOIN is fast, but selecting column is slow Do I need to add an index to EVERY column in a JOINED table if that column will appear in the ...
5
votes
2answers
140 views

Optimizing “WHERE x BETWEEN a AND b GROUP BY y” query

CREATE TABLE test_table ( id uuid NOT NULL, "RefId" uuid NOT NULL, "timestampCol" timestamp without time zone NOT NULL, "bigint1" bigint NOT NULL, "bigint2" bigint NOT NULL, "int1" integer ...
0
votes
1answer
36 views

Order by reduces performance of a grouped result set

I'm trying to optimize a query which uses a combination of GROUP BY and ORDER BY which together cause a big performance hit (~x15). If I remove either of the conditions, the query runs pretty fast. I ...
1
vote
0answers
44 views

Why not create ColumnStore index on every single table?

As ColumnStore index improves performance for data warehouse databases, and also since SQL 2104, it is updatable too, why not creating ColumnStore index on every single table? Edit: In SQL 2014 we ...
0
votes
1answer
39 views

Better way of re-arranging the indexes for better performance

I ran a script to find overlapped and duplicate indexes for a database. Below is the sample screen for the above said. Please advise how can I arrange them or what should be the guidelines to make ...
0
votes
0answers
27 views

Can one database affect the performance of another in MongoDB?

We have a fairly beefy server (15 GB RAM, 2 cores) running a reasonably large MongoDB instance. The Mongo instance hosts two separate databases that communicate via application code. The larger ...
1
vote
1answer
491 views

memory usage oracle query

We see Direct path read temp frequently in the database. It started with one query and later followed up to all the queries running in database at that moment. I understand that data is read from ...
0
votes
0answers
28 views

Query runs 10 times slower on one node compared to another using the same database

I have got an AlwaysOn database on two nodes and have discovered that the same query takes less than half a second to run on one node but around 7 seconds on the other one. It doesn’t matter whether ...
2
votes
1answer
33 views

How can I implement a viewed system for my website's posts?

Here is my current structure: // posts +----+--------+----------+-----------+------------+ | id | title | content | author_id | date_time | +----+--------+----------+-----------+------------+ | 1 ...
1
vote
1answer
860 views

MySQL: Optimize query with a range and distinct count

I have a query on a large table with millions of rows that looks like this: SELECT COUNT( DISTINCT clicks.tx_id ) AS unique_clicks_count , clicks.offer_id FROM clicks WHERE ...
22
votes
2answers
17k views

Optimizing bulk update performance in PostgreSQL

Using PG 9.1 on Ubuntu 12.04. It currently takes up to 24h for us to run a large set of UPDATE statements on a database, which are of the form: UPDATE table SET field1 = constant1, field2 = ...
1
vote
3answers
50 views

How do I prevent multiple row insert?

I set up a playground MySQL database for users and I'd like to prevent multiple row (large) inserts. That is, if there will be over N rows after INSERT operation, then raise an error and do not ...