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.

learn more… | top users | synonyms

1
vote
1answer
37 views

Update by iterating table in batches faster than whole table in PostgreSQL

I have a table with approximately one million rows. It is being used in production and I ran an UPDATE which covers ~95% of those rows. After five hours I cancelled the request because it was taking ...
0
votes
0answers
38 views

MySQL performance affected by calling functions from inside procedures?

this is the very first question I post, so please bear with me ... When working on a project, I tried to get the LAST_INSERT_ID for a table, by invoking it from inside a procedure right after an ...
-2
votes
2answers
116 views

Random numeric string as a primary key - security, performance, efficiency?

I'm building an app aimed to store lots of records (millions) and trying to find a best way to store records identifiers that is publicly accessible from the web (record URL). I'd like to get: ...
0
votes
0answers
18 views

Sudden performance gain when performing mysql queries twice, lacking on live host

I was having performance problems and could improve it down to 14 seconds roughly per execution (if you see any way to improve that further, I would be really thankful). Which, is still very slow. ...
5
votes
1answer
176 views

How does SQL Server calculate the initial size of a (compressed) backup?

When a backup is created, SQL Server guesses(?) the a size of the intial backup file. Later on, maybe when it appends the log the size will be re-adjusted, sometimes multiple times until the final ...
1
vote
0answers
43 views

Improving PostgreSQL cluster performance

I am trying to cluster my table faster. The table is 27 GB worth of data, and has one index using a point geometry which is 19 GB in size. I am seeing about 5.5 hours to cluster the table. I am ...
3
votes
1answer
54 views

Are database connections from an application expensive from a performance point of view?

A colleague tells me that connections to a database are expensive and could harm performance of the application. They ask me to create a procedure that calls say another 8 procedures, that way they ...
2
votes
2answers
66 views

Performance issue during count Postresql 9.4 - Creating index on pivot table key…?

Disclaimer: I am new to Postgres, I need some advice... I have a huge table, with full of poker hands.(will contain 20M records, right now 2M records in it) aggregated_hands I have a pivot table, ...
3
votes
2answers
148 views

SQL Server transferring results slowly in table result set, but instantly with XML

I have a query that left joins 100+ tables and returns 2,000+ columns, but only a few rows (10-20). This part is out of my control at the moment and it used to run ok with a bit fewer columns (maybe ...
0
votes
2answers
61 views

How to improve performance of frequently updated table in mysql?

my table structure:: CREATE TABLE `gps_device_data`( `imei_no` bigint(15) NOT NULL DEFAULT '0', `ioelementpriority` int(1) DEFAULT NULL, `longitude` int(15) DEFAULT NULL, `latitude` int(15) ...
0
votes
2answers
71 views

Best way to update list of rows in oracle database

I need to update a variable list of database rows. The list of the affected ids will be generated by an application, the statement will be executed about 100 times a day (with an always different ...
0
votes
0answers
27 views

Correlating Disk Latency on Application side Vs. EMC SAN

Our OLTP databases have encountered several I/O issues. During those events: Avg disk sec read on the data file was 0.2 second or higher We found windows eventlog entries stating: "SQL Server has ...
6
votes
2answers
294 views

Doubts in a Glenn Berry Query ( CPU per Database )

Please, if this is not place to post questions like these, let me know and I will delete it. Inside the Glenn berry's Diagnostic queries, there is a query to show how much CPU a database is using. ...
0
votes
0answers
803 views

MySQL 5.7 InnoDB is extremely slow on spatial data compared to MySQL 5.6

I have a table area which contains ~300,000 rows. It is defined as follows: CREATE TABLE `area` ( `area_id` bigint(20) NOT NULL AUTO_INCREMENT, `boundary` geometry NOT NULL, `name` varchar(255) ...
1
vote
0answers
27 views

PostgreSQL: labels vs columns

I have a data structure similar to this: date foo bar baz boo ---------------------------------------- 2015-11-18 1 null 2.5 81.0 2015-11-19 1 78.4 12.8 ...
4
votes
1answer
78 views

SQL Server Memory Shrinking

I had a strange issue today on a 3rd party vendor's SQL Server. This is a VM running SQL Server 2012 SP1. The min and max memory settings are set to 9GB. Task manager showed SQL Server was getting the ...
0
votes
1answer
206 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
0answers
19 views

Need some advice on db layout

I have some data that gets exported from a different system that I want to suck into mysql for some analysis. Currently, the export consists of 2 files, essentially file1 is the list of transactions ...
2
votes
1answer
83 views

Disk I/O Utilization at 95%

My disk I/O utilization is at 95% at my MySQL server. What are steps I could take to fix this? It is a Ubuntu VP with 16 GB Memory and 8 cores. Here is a screen-shot of the load:
0
votes
1answer
49 views

Does LIMIT 1 still have effect on a unique column

I know that adding LIMIT 1 when searching for only one record makes a lot of difference when it comes to performance. But does it still have any effect when we search a column with a unique ...
0
votes
0answers
26 views

Does extending datafiles affect performance

We have an Oracle 10.2.0.3.0 on Windows 2003 Server which is scheduled for upgrade within the next six months. One tablespace is about 2TB in size with over 250 data files. Some of these were ...
3
votes
1answer
534 views

What does “cleaning up” mean in MySQL InnoDB transaction status and how to prevent it?

In our database (MySQL 5.6.22 on RDS) we have a lot of transactions (~500) in a state "cleaning up" under the load: > SHOW ENGINE innodb STATUS; ... ------------ TRANSACTIONS ------------ ... ...
0
votes
0answers
23 views

Performance issue for daily calculations - Sybase Adaptive Server

I need an advice from the community, there is no wrong answer I'd like to have as many advice that I can ! I manage a process that does every day a lot of financial calculations and they are ...
0
votes
1answer
38 views

Consultants using old version of Hibernate ORM for new application - should I be concerned?

My company currently has consultants developing a Java-based application. They are using Hibernate ORM 3.5 (released 5 1/2 years ago in 2010) in this application. The back-end is SQL Server 2012. ...
0
votes
1answer
31 views

Large Sleep counts causing THREADPOOL wait?

When I run sp_whoisactive throughout the day, I usually see we have around 500-700 connections on our server. We are occasionally getting threadpool waits and high signal wait ratios (so we are thread ...
2
votes
3answers
126 views

Why do large images stored in database hurt performance [closed]

I have read on the internet that it is better to keep large images on file systems since storing them in the database hurts performance. My question is why do large images hurt db performance?
2
votes
2answers
90 views

Merge two huge tables keeping only the unique rows

I have two tables: table1 with 61 million rows and table2 with 59 millions rows. The columns in both are the same (name and type). Both are imported from backup files. I want to merge these two ...
10
votes
1answer
1k views

Why are multiple COUNT faster than one SUM with CASE?

I wanted to know which of the following two approaches is faster: 1) Three COUNT: SELECT Approved = (SELECT COUNT(*) FROM dbo.Claims d WHERE d.Status = 'Approved'), Valid ...
2
votes
1answer
116 views

Is it ok to have 'view count' column in the same table?

Let's say I have a website similar to YouTube where I'm storing and displaying the 'view counts' for each video. It is ok if I'm storing the view count column in the same table as the actual view ...
8
votes
2answers
149 views

Why is TOP operation in SQL execution plan

After searching for a while, I decided to post this question for lack of finding an answer and apologize if there is a similar question/answer out there. When running the query below on two similarly ...
7
votes
5answers
615 views

How to update 10 million+ rows in MySQL single table as Fast as possible?

Using MySQL 5.6 with InnoDB storage engine for most of the tables. InnoDB buffer pool size is 15 GB and Innodb DB + indexes are around 10 GB. Server has 32GB RAM and is running Cent OS 7 x64. I have ...
2
votes
2answers
94 views

How to retrieve Oracle Key Performance Indicators in 5 minute intervals within a time range

I have Oracle 11g attached to a Performance Test environment. A performance test runs for two hours. After the run I want to programmatically extract a variety of in key indicators from the database ...
0
votes
1answer
86 views

Slow query log on production?

What are the best practices regarding the slow query log? Should it be active in production environment? If so, what would be a reasonable long query time? I know its different for every application, ...
0
votes
0answers
52 views

MySQL query hanging while copying to tmp table

I have a query that ran in 10+ seconds last week, but now is hanging even after 10 minutes. I'm running this in a test environment so the data hasn't changed much and I am baffled at what could be ...
0
votes
1answer
87 views

SQL Server Memory Cap reached its maximum state and threw an Out Of Memory Exception

We have set a memory cap limit of 43GB in SQL server instance, so thereafter it keeps 42 GB near about and keeps near about 1 GB for its processing operations. But then we received near about 500,000 ...
3
votes
1answer
107 views

Select performance problems with conditional index vs non-conditional on large volume table

We are trying to change some indexes on a large-volume table to be conditional indexes (function-based indexes) to reduce how much space is being used for indexes against this table. When testing the ...
0
votes
0answers
31 views

Any risks to pure inserts + delete duplicates, instead of insert/ update for SQL Server?

I saw a related question but it was more of the how vs. the why. I'm wondering in SQL Server why one would attempt an "insert/ update" with incoming data ... instead of just running pure inserts ... ...
1
vote
1answer
39 views

Is there an actual problem in my storage IO or is the data incorrect?

Running SP_Blitz indicated that I have a slow read/write performance on my drives. Reading further, I eventually landed on this query to view the actual statistics of IO occurring on my drives: ...
0
votes
0answers
43 views

MySQL database hangs but less CPU

I create an application for 30 concurrent users using C# and InnoDB of MySQL (mysql-5.1.35). The size of database is more than 100M lines (~20GB). Most of data is come from 7 active table (2M ...
1
vote
0answers
140 views

Mongodb Huge Number of Open Connections and Write Locks

We are seeing around 800 open connections to our Mongodb. To clarify our issue: We have 5 different clients who write the data into Mongodb. Each of these clients - write four different type of ...
5
votes
0answers
249 views

Performance inner join vs left join involving parallelism

I have a query which takes about 8 hours to finish. Simplified, the query looks something like this: SELECT [Some attributes, inconsequential] FROM RBM.Financial_Events RFE INNER JOIN ...
1
vote
2answers
161 views

Faster query when joining data from multiple tables

I’m looking for a way to make a database query faster. The table parts has over 6 million rows. Each part row is associated with the manufacturers table (a couple hundred rows) by ID. When searching ...
2
votes
0answers
117 views

Materialized View - vs. New Calculated table for performance [closed]

I have a problem - I'm trying to de-normalize data tables in a data warehouse in preparation for use in the Business Intelligence/ Presentation layer. By denormalize I mean create a series of joins. ...
2
votes
0answers
25 views

Implications of many materialized views in Postgres?

I'm working on a system that includes a scheduling component, which has support for recurring events. After reading many, many posts on storing recurring events, it was suggested that they be ...
0
votes
0answers
49 views

How to tune a sql server for a specific process in particular?

I have a specific process that I am want to tune for in a sql server DEV server. The DEV server and the LIVE server are equal, just the DEV has less memory. Both LIVE and DEV read data from the same ...
2
votes
2answers
58 views

How to optimize performance of backup process? Servers go down during backup

The context - So I am an intern (So I'll appreciate a more noob friendly response) and we have several websites on a server of which we do a backup daily, at midnight. We use MongoDB and there's a ...
0
votes
1answer
101 views

What's the biggest bottleneck (time) in writing data to a SQL database?

I'm running an ETL process that is writing about 2 million rows to a SQL Server database. I'm trying to optimize the time it takes for pure inserts (I guess updates is a different story). I'm ...
0
votes
0answers
34 views

Increasing system load due to multiple inserts every millisecond

In my project I need to do multiple database inserts every millisecond and thus Postgres takes huge amount of CPU. I need to find a way to reduce CPU load as I need to process about millions of rows. ...
0
votes
2answers
177 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 ...
0
votes
0answers
105 views

Performance: Postgres (Read-Committed) vs MySQL (Read-Uncommitted)

I have a workload that involves very frequent writes and reads. It is very performance sensitive, but not accuracy-sensitive. Hence, to maximize performance and minimize locking-delays, my plan was to ...