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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1answer
408 views

Internal query on CDEF$ and CON$ very CPU bound

I am checking an application (Infor ERP LN) that loads a lot of data into an oracle 10.2 database. While checking one of the user sessions with SQL_TRACE and its output with tkprof, I found that the ...
0
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0answers
32 views

Improve Query Performance

I have the following sqlite3-Tables: db.execute("""CREATE TABLE IF NOT EXISTS STATIONS (StationUID INTEGER PRIMARY KEY AUTOINCREMENT, StationNumber TEXT NOT NULL, ...
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1answer
23 views

InnoDB Table has backed up INSERT and UPDATE queries, high CPU

I am running an MySQL DB with all InnoDB tables. I often have many queries backed up for the same table when I run SHOW PROCESSLIST; Basically, I keep a table of every logged in customer and update ...
3
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2answers
409 views

Query planner thinks doing a sequential scan on a very large table is faster than using an index?

I've got a query that selects the most favorited photo for each of the last 12 editions for a particular domain (this is just a segment of a larger query, but the problem seems to stem from here): ...
2
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1answer
1k views

Mysql search matching multiple values in multiple columns

I need to speed up a search. Currently we let our users input a name: John Doe Then in Java we split that string to create multiple values (or "terms") ["John", "Doe"] and loop through the terms ...
2
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1answer
321 views

Best design of mongo replica set for DB read/write speed

I'm building a Node app that uses MongoDB. Whilst it would probably be fine to have node and mongo sitting on the same VPS, I want to ensure that the MongoDB is backed up and maintain high ...
0
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1answer
30 views

Can mutli-threading java client cause high CPU utilization of SQL Server 2008?

I am a Java Developer, not a DBA, and would like to consult about an issue encountered in high CPU utilization in the SQL Server 2008 (not in the Java app server). The Java client uses ...
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1answer
274 views

Designing a High Score/Leaderboard table

I'm looking for input on how to design a highscore table for a game I'm creating. The database I'm using is postgres. That's not really something I can or want to change (unless there's very good ...
5
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2answers
186 views

Feasible to have thousands of users in Postgres?

We are creating SAAS where we will at most have 50.000 customers. We are considering creating a user in the Postgres database for each customer. We will map each user that logs into our service to a ...
1
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1answer
144 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 ...
3
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0answers
84 views

Can't get Dell PE T420 (Perc H710) perform better than a MacMini with PostgreSQL

It's months that I'm trying to solve a performance issue with PostgreSQL. SYSTEM CONFIGURATION Our deployment machine is a Dell PowerEdge T420 with a Perc H710 RAID controller configured in this ...
0
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1answer
121 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.
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1answer
38 views

What will be the Better database design for following table? [on hold]

I am designing database schema for bulk mail system. campaign table is used to store the campaign details. Table Campaign ...
3
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2answers
462 views

SQL server query is slow *without* including execution plan

I have just set up fresh installation of SQL Server 2012 on a new server and I'm experiencing very strange performance problems. Long story short, for some reason not including execution plan makes my ...
2
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0answers
37 views

Case Statements, subqueries, and datediff

First time posting on this website so please let me know if you require any other information. This first section of code worked perfectly and resulted in correct information. [Field 1] = (CASE ...
2
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0answers
44 views

How to resolve RESOURCE_SEMAPHORE and RESOURCE_SEMAPHORE_QUERY_COMPILE wait types

We are trying to figure out root cause of slow running sql server queries hitting/fetching data from one of the database , size 300 GB, hosted on server with below configuration: Windows server ...
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0answers
18 views

DB space vs query complexity tradeoff

I have a dilemma - Right now I have a query that I do constantly - joining 5 tables on different columns, calculate stuff per row, distinct on that, and do that with offset and limit (pagination). I ...
0
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1answer
234 views

MySql - is possible that performance issues are caused by dynamic SQL?

We have this MySQL SP, which uses dynamic SQL. It seems it does NOT perform well under load. It is possible that this SP becomes slow under load because it uses dynamic SQL? Can dynamic SQL cause ...
3
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2answers
232 views

RAID10 vs. RAID5 for data files

We are trying to evaluate the potential performance improvements that could be gained by switching an existing applications .mdf files to a RAID10 LUN vs. the existing RAID5 LUN they are living on ...
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3answers
24 views

MySQL Date field: filter by LIKE vs MONTH()

I have a CRON task that needs to extract customers with birthday in a given month, from a MySQL INNODB table. The birthday field is indexed and of type DATE. I can query the customers table by either ...
0
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2answers
191 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
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0answers
17 views

Accounting Program Error [closed]

I have Oracle Application R12 running on 11g. The error occurs in Accounting Program when we are running Create Accounting session in Payable Module. When we click on Diagnostics it gives this ...
0
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1answer
85 views

SQL server not using the memory allocated

We have noticed that for one of our SQL server with below configuration ,memory is not getting availed as allocated. SQL server 2005 SP4, 32 bit Windows server 2003 R2 SP2, 32 bit with 16 GB ...
8
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5answers
15k views

Fastest way to check if InnoDB table has changed

My application is very database intensive. Currently, I'm running MySQL 5.5.19 and using MyISAM, but I'm in the process of migrating to InnoDB. The only problem left is checksum performance. My ...
0
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1answer
70 views

Most efficient way to set up a database handling millions of links? [on hold]

I'm looking at making a site that will potentially have up to a million users, and each user will have hundreds/thousands of links connected to a set of sites, as well as other info. I'm using mysql ...
0
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1answer
15 views

I have a DB that is locking up from numerous updates to a table: Should I convert it from MyISAM to InnoDB?

FYI: I don't believe this is a duplicate question, I've looked and most are general questions with vague answers. See more specifics below: Currently a database I am in charge of locks up every once ...
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2answers
182 views

Is it a good idea to include a value column (e.g. from measurements) in an index?

Is it a good idea to include a value column into an index for a table which has many million rows? For example a measurement table which looks kind of like this: CREATE TABLE measurements ( id ...
2
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1answer
738 views

PostgreSQL partitioning query performance inexplicably bad

I find this a bit mysterious. The cost of getting the maximum value out of just the partition parent table (which is empty) is very cheap: evlampts=# explain select max(timestamp) from only mcdata; ...
0
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1answer
745 views

How to configure my.cnf for Mysql 5.1, which is using too much CPU?

I am new Database engineer. I am having trouble in my server which is using too much CPU on database query(simple count statement). I have googled about it, so i found out it depends on system ...
2
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1answer
238 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 ...
0
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1answer
50 views

Best way to rank all the columns in a table and store those ranks in another table

I have SQL Server 2008 and a table w/ hundreds of thousands of records and about 50 columns. I run a sql statement like: Select rank() over(order by col1 desc) as Col1Rank, rank() over(order by ...
1
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1answer
44 views

Poor query performance due to recheck condition on index scan

We are testing the performance of metadata when stored in JSONB compared to a traditional EAV catalogue (commonly used in biomedical scenarios), using a PostgreSQL 9.4 server. I get a problem when ...
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1answer
95 views

How can I improve this update?

I'm working with SQL Server 2014 Express edition and I want to upload some OpenStreetMaps data. Data is a 172 Mb XML and it loads ok. The problem is with this script: UPDATE ways SET geog4326 = ...
2
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1answer
272 views

Is this amount of disk IO expected with MySQL?

I am running MySQL 5.5.34 on an Amazon EC2 micro instance with EBS (elastic block storage). The instance has been running for around 10 days and according to Amazon I've accumulated around 8.5 ...
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1answer
160 views

Handling a chat room in a database

I have been searching all day to find a better answer to my question but those I found was useful but do not critically analyse my question. I am building a chat room using php, mysql, jquery and ...
1
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1answer
26 views

Can the number of tables and functions affect performance? [closed]

I have some big database with hundreds of functions and tables. They also have a lot of sequences, custom types and some views and triggers. There is a point when the quantity of objects will be a ...
0
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2answers
155 views

Slow INSERT/UPDATE on InnoDB

I have a problem with the performance of my MySQL server, let me explain: I instaled a MySQL server, version 5.5.20 Server version: 5.5.20-log Source distribution SELECT queries runs fast on ...
1
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0answers
19 views

SQL - Optimize table population with dynamic queries

I need to optimize the following pl/sql procedure. So, fundamentally my question is: There is a way you can do a bulk insert in a pl/sql that could be more efficient than loop through an associative ...
0
votes
1answer
361 views

Difference between FIND_IN_SET and LIKE

is there a difference in behavior or performance in choosing FIND_IN_SET over LIKE for a operation that looks like: SELECT * FROM my_table WHERE column_1 LIKE %string% vs SELECT * FROM my_table ...
22
votes
5answers
9k views

Why would I NOT use the SQL Server option “optimize for ad hoc workloads”?

I've been reading some great articles regarding SQL Server plan caching by Kimberly Tripp such as this one: http://www.sqlskills.com/blogs/kimberly/plan-cache-and-optimizing-for-adhoc-workloads/ Why ...
0
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0answers
44 views

SQL Server performance is slow when migrated from SQL Server 2012 to SQL Server 2014

We are trying to migrate from SQL Server 2012 to SQL Server 2014 on Windows 2012 R2 OS. After the upgrade, we are doing performance testing and observed huge difference in running a simple query from ...
2
votes
1answer
126 views

PostgreSQL performance worse when adding CPUs

I ran into a strange behaviour when benchmarking PostgreSQL. The setup is like this: Virtual box VM, with 3 GB of RAM. The host has 16GB of RAM and 4 CPUs. Ubuntu 14.04, standard PostgreSQL 9.3 ...
1
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1answer
1k views

MySQL: Which join is better between left outer join and inner join

Which join is better peforming if all of them provides the same result? For example, I have a two tables employees(emp_id,name, address, designation, age, sex) and work_log(emp_id,date,hours_wored). ...
0
votes
2answers
133 views

What's faster: two UPDATEs with WHERE (in / not in) or one UPDATE with CASE?

What's best performance wise, two separate UPDATEs: UPDATE table1 SET enabled = 0 WHERE code NOT IN ( SELECT id FROM table2 ); UPDATE table1 SET enabled = 1 WHERE ...
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0answers
10 views

PostgreSQL analyze only parent table only

I am moving data from a few billion records table to newly created partitions. I am inserting into the child table directly and deleting from the main table with filters on the appropriate columns in ...
1
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1answer
268 views

DB disk space requirements comparision between MySQL versions

I have 2 labs where MySQL is installed. DataBases are created and deleted dynamically by certain internal processes. InnoDB is the Engine used. In one lab, MySQL version 5.0.77 is installed. The DB ...
0
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2answers
218 views

MySQL/MariaDB Limitations

we're running MariaDB on our DB server. We have to install multiple databases on each DB instance (in fact each DB server runs multiple MariaDB instances) because each database must be separated. ...
0
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1answer
56 views

How to speed up mysql query against a 204 million record table

For some reason my server has been finicky lately and for the life of me I can't figure out why. I monitor the memory usage by running shell# watch -n 5 free -m without running any activities ...
2
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1answer
125 views

What are possible causes for consistently volatile INSERT performance in MySQL tables?

I have a Java program running on a VM that is sequentially feeding a queue of single row INSERTs through a single connection to a MySQL server on the same VM. The queue execution is not artificially ...
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1answer
12 views

Requests to local CouchDB have 40ms latency

Requests to a CouchDB instance on the same machine have about 40ms latency when HTTP keepalive is used by the client, about 0-1ms latency when the client does not use keepalive. What causes this ...