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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19 views

Question about MySQL triggers performance

I currently have a database that stores some transactions for several users, for example purchasing or selling products is stored as 1 entry in the transactions table. It can also store profits made ...
3
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1answer
814 views

Do OR conditions in Oracle SQL queries spoil index use / cause full table scan?

I have a query on Oracle 11g of the following type, which results in a series of highly inefficient full table scans: select t.Id, t.ObjectId, t...[other Tasks columns] , od1...[ObjectData1 ...
2
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1answer
32 views

Database design - summary table vs always counting over tables

Imagine a system where a user can make a whole lot of different actions, like: Making a purchase Liking something Opening a specific view (pretty much every click) Inviting a friend ... The ...
2
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2answers
158 views

What is the fastest way to clone/copy oracle databases on the same machine?

I want to clone oracle databases on the same machine and I need to change user etc. from e.g. PROD to DEV. For that I use expdp/impdp, but this tends to be slow with increasing database size. I need ...
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1answer
24 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 ...
9
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2answers
266 views

Find rows where integer sequence contains a given subsequence

Problem Note: I refer to the mathematical sequences, not the sequences mechanism of PostgreSQL. I have a table representing sequences of integers. The definition is: CREATE TABLE sequences ( id ...
40
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6answers
40k views

About single threaded versus multithreaded databases performance

H2 is a single threaded database with a good reputation regarding performance. Other databases are multi-threaded. My question is: when does a multi-thread database become more interesting than an ...
6
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2answers
3k views

Why is my Azure SQL Server so slow?

We currently have a VM that is very underpowered and are proposing to move to an Azure VM with better specs. The problem is, the Azure VM is much slower than the original VM even though it is of a ...
0
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2answers
599 views

my.ini configuration for a huge server

I have developed a web based app in PHP MySQL and Flash Builder. It was running fine until a few days ago when the client began to connect a lot of users. Then the app started to freeze and sent ...
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1answer
50 views

Some tables don't have primary key, how can I fix this issue?

I have the following message when running myqsltunner.pl in past this was not present. How can I solve this issues? -------- Galera Metrics ------------------------------------------------------ [...
12
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2answers
421 views

Minimizing Indexed Reads with Complex Criteria

I'm optimizing a Firebird 2.5 database of work tickets. They're stored in a table declared as such: CREATE TABLE TICKETS ( TICKET_ID id PRIMARY KEY, JOB_ID id, ACTION_ID id, STATUS str256 ...
1
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1answer
120 views

Error in loading data using DB2 load command in DB2 10.5 [on hold]

I have a IBM DB2 database in our application. We have a monthly Java batch process which loads data in the tables using "load Replace" sql command. Around millions of record will be updated every ...
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0answers
24 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 ...
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0answers
13 views

Get missing index statistics in SQL Server 2014 [duplicate]

For example consider a database that has many SP and many query execute on it using ORMs. It's very time consuming that check every SP or profile all queries that ORMs generate for performance and ...
1
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0answers
58 views

Fastest way to shred large xml data into a table

I have a nightly process that shreds XML data from a 17 million row table (120 GB) into another table, it takes about 3 hours and inserts about 1.5 million records. I currently do a complete drop ...
3
votes
1answer
3k 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 ...
0
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1answer
18 views

Do dormant databases impact server performance?

On our web server, my team has been creating new databases in MySQL to manage backups. They simply create new database_DATE and copy over our live site. Which made me think today... Can having a ...
7
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3answers
473 views

Single service account running all SQL Servers

Is there any negative performance impact for using the same service account and agent account to run SQL Server and SQL Agent respectively for all SQL server instances running at a small company of ...
8
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1answer
1k views

What frequency of hash/sort spills into tempdb is concerning?

Our enterprise application uses SQL Server for data storage and is primarily an OLTP system. However, an important component of our application generates a significant OLAP workload. Our write ...
0
votes
1answer
135 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 ...
6
votes
3answers
13k views

Mysql slowly uses memory until it starts to use swap

I am running a 1gb of RAM rackspace database server. For some reason in about 2 days the memory usage goes from using very little swap, to using 100mb. If I don't restart sql it will keep using more ...
1
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0answers
44 views

ms/write on tempdb data files are dead slow

I don't know why writes on my tempdb data files are extremely slow. ms/write on each of the tempdb data files reaches to more than 800 ms!!! that's even after I moved the 8 equally sized (7GB) tempdb ...
2
votes
1answer
200 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 ...
3
votes
3answers
67 views

IN Clause - listing values VS query

My app runs a lot of queries like this SELECT ... FROM Table WHERE CategoryID IN (SELECT CategoryID FROM OtherTable WHERE ..) To save performance I decided to cache the second subquery in the ...
3
votes
1answer
656 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....
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votes
1answer
146 views

How to achieve high performance management of a huge list of distinct strings [closed]

I am trying to achieve high performance management of a huge list of distinct strings in SQL Server (but I'm open to suggestions of alternate platforms that might be more performant). My specific use ...
2
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2answers
679 views

Mysql improve Self join performance large table?

I have a task to help identify conflicting IP ranges , I want to highlight when one companies IP range falls within another's ... below is the sample table, I have converted the IP ranges from .dot ...
15
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3answers
6k views

Is the overhead of frequent query cache invalidation ever worth it?

I'm currently working on a MySQL database where we are seeing a large number of invalidations from the query cache, primarily because of the high number of INSERT, DELETE and UPDATE statements that ...
0
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0answers
32 views

MySQL insert with sub select slow

We are using Python and LOAD DATA INFILE to load data from CSVs into our staging database. From staging we have sql scripts moving the data into our actual production database. LOAD DATA INFILE is ...
0
votes
1answer
186 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
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1answer
33 views

How costly are InnoDB rollbacks?

I recently heard a fellow co-worker mention that InnoDB rollbacks are costly and negatively impact performance. How true is this statement? To give a context, we use spring+hibernate and set @...
0
votes
1answer
356 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 ...
2
votes
3answers
775 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 ?
2
votes
3answers
161 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 ...
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2answers
28 views

MySQL CREATE INDEX slowing down

My analytics table has 190M rows, about 150GB ins size. Storage engine is MyISAM with key-buffer-size=16G myisam_sort_buffer_size=2G myisam-max-sort-file-size=200G. Machine has 32GB memory. While ...
0
votes
2answers
227 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
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0answers
54 views

select * into taking too long

I have an SP where we preselect some data into temp tables using select * into. From my understanding it doesnt copy over index,constraints. For last week i have seeing performance difference for ...
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votes
1answer
66 views

How much data in one table before it hurts performance

I'm about to develop a database for a community. The database is MS SQL Server. Each user can create their own shop where they can advertise about their products. So let's say I create a table to ...
2
votes
0answers
90 views

designing mysql for large tables

Currently I've been assigned the task to research ways to speed up an existing project. It's going to be rebuild so we can start from scratch, the current implementation has been build by another ...
3
votes
0answers
69 views

Sample a Mysql table to increase performance

we are storing all our clients traffic data in a MySQL 5.1.73 database (MyISAM) and then we use it to generate user and internal statistics/graphs, always searchinng for a client id and a date/hour. ...
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4answers
247 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 ...
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 ...
1
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1answer
414 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
2answers
2k 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 ...
16
votes
2answers
404 views

Using MAX text or more specific, smaller type

Someone was reviewing my DDL code for creating tables and suggested, when they saw I saw using VARCHAR(256) fields for text I expect to be pretty small, like a first name or whatever, that I should ...
2
votes
2answers
167 views

Select the maximum aggregate value for a limited set of chunked/grouped rows in a large database?

I work on WordPress plugin which implements sitemap functionality. One of the steps is to build an index of sitemap pages for post entries. The logic required is roughly: determine last modified time ...
2
votes
1answer
556 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
votes
1answer
115 views

Speed up query that have joined tables and function calls

I have a Bootstrap Table that use server side pagination to display results from a query like this: SELECT Item.a, Item.b, Item.c, Info1.Name, Info1.Name, Info2.Name, ...
0
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1answer
113 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" ...