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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0
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3 views

Is it good to save Keywords stored by users in a new DB schema?

My question is more from the schema design and of further performance of the DB. I'm designing a DB schema which will store primarily strings. Actually, users work on these string, as normal mortals, ...
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1answer
16 views

MongoDB 3.0 Indexes maximum limitation

I have a mongo DB that store user's public messages. Each message should be categorized by at least one TAG (3 max in an array) The TAG can be anything up to 32 characters. ([0..9a..z]) the Tag ...
2
votes
1answer
39 views

Deleting large amounts of cascading records with minimal locking

I'm looking for a strategy to purge large amounts of logically deleted data from a MySQL database. The deleted records are in a relatively small table, but are referred to with many ON DELETE CASACDE ...
0
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1answer
51 views

Is adding the join columns to a table a good practice to improve performance?

Say we have 3 tables, A, B and C. Assume all table relationships I refer to below are 1 to many. Suppose A joins B in a1 = b1 and B joins C in b2 = c1. Is it a good practice to add b2 and a1 to ...
2
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1answer
363 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 ...
5
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4answers
6k 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 ...
0
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1answer
28 views

Fastest way to do bulk import in MYSQL

I have got a question about the fastest way to copy a large number of records (around 10 million) from 1 table to another in MySQL. The target table has 1 primary key, 4 indexes and 3 foreign key ...
1
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0answers
19 views

Slow inserts in oracle 12c inmemory table

We are running some tests to check the in-memory performance on a 12c (12.1.0.2.4 EE) RAC. Servers have 56GB memory and 20core CPUs. Our plan is to have a few read-performance critical tables in ...
0
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1answer
43 views

Mysql Slow when join query running increaed

Our Mysql dedicated server box always have around 40 - 80 active user connection , so the query speed very good and Cpu usage low . (around 4 - 8 core from 24 core) but sometimes when some wordpress ...
4
votes
3answers
139 views

Setting maxdop 1 vs setting the threshold for parallelism high

I am looking at a possible fringe case for parallelism settings. I've long since followed the credence that maxdop 1 is a viable option for Microsoft Dynamics CRM databases. As the nature of the ...
0
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1answer
213 views

Select Query takes more than a minute to retrieve data

I have a table that has 99 columns, all of them are not needed but they were there when we started. There is a Primary Key (Objectuid) which is a GUI and has the Clustered Index on the PK. The Table ...
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 ...
2
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0answers
43 views

ASP.NET & SQL Server 2012 timeouts once a month

We have an intranet site which works fine, except one day a month. There are slow queries, unoptimized tables, tables with ~8 million records, etc. but daily usage is fine, although some ...
5
votes
1answer
260 views

What units is Page Life Expectancy in?

I'm currently using the following query to get the Page Life Expectancy from SQL Server: declare @PLE int select @PLE=cntr_value from psql1.master.sys.dm_os_performance_counters where ...
5
votes
1answer
47 views

How can I minimize impact of expensive queries in Database A on Databases B, C, D

How can I configure SQL Server so that activity in 'Database A" has minimal impact on users in 'Database B' The Context Our (very large) production SQL Servers have a lot of databases on them ...
7
votes
1answer
105 views

Instant File Initialization on Shared drive

I asked something similar to this before, but previously I had asked about moving backups to a shared location. This time I am curious: if I want to restore a database on a shared drive, do I need to ...
7
votes
0answers
54 views

Two servers, different execution plans. Several orders of magnitude difference in run time

Two servers, Development and Live. Live server is an Amazon RDS SQL Server Web instance. Both servers have identical schema and data. There is a good spatial index on the geometry column. On my ...
7
votes
1answer
90 views

Low CPU Utilization but High Signal Waits

I have a server with 16 CPUs that is configured with a max degree of parallelism of 8 and a max worker threads setting of zero. For a given hour, my signal waits were 20% yet my OS CPU utilization ...
5
votes
2answers
2k views

Linked Server Risks

I'm implementing a new feature which requires data from databases on multiple servers. I just need to union data from all these servers and sort it. The two options that come to mind are: Use linked ...
2
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2answers
183 views

where is the index physically located in MySQL database

Just wondering where is the index info physically located in MySQL database if I have indexed a table with ALTER TABLE contacts ADD KEY (columnName); ? it will stay with that table and add a new ...
1
vote
1answer
205 views

MongoDB Insert Performance

I have some data which are aggregated in chunks and later pushed into another collection. The problem is that aggregated data pushing to another collection is very slow and takes from few hours and i ...
2
votes
1answer
718 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 ...
3
votes
1answer
52 views

4m Rows in MySQL, ~5 Minutes to Run Query

I have 2 tables, a users table and a log table which literally logs each time a user signs in. What I'm trying to do is grab a list of all users with a certain rank who have not logged in for over a ...
1
vote
1answer
31 views

Why is my Target Server Memory slightly higher than my Total Server Memory?

I'm doing a performance test on a high traffic (16000+ users, estimated 1000+ concurrent at peak) Microsoft Dynamics database. The server has gone on line a few months ago, and I'm doing some tests to ...
1
vote
3answers
326 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
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0answers
24 views

Best database for select operation? [closed]

I have a mysql database that contains 20M row and it's size is about 1.3 GB. Database schema is | id | name | no I just want to make faster query to search a number in db.(<300ms) Should I ...
9
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5answers
11k views

Why using innodb_file_per_table?

There are many articles exaggerating (IMHO of course) the need for innodb_file_per_table. I understand that with innodb_file_per_table, there should be a better control over the individual tables; ...
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0answers
14 views

My SSMS is running too slow [closed]

My SQL Server Management Studios running too slow. This is my local server. For each query, executing taking place longer time. The databases I have are Adventureworks2012, AdventureworksDW2012. Doing ...
6
votes
2answers
1k views

How to calculate cache misses for PostgreSQL

I'm administering a server where a tool using a PostgreSQL runs. The tool takes care of most PostgreSQL configurations by itself, but I'm observing some performance problems. I could confirm at OS ...
0
votes
1answer
212 views

MYSQL: How to improve performance of inserting over 1M rows to a table with over 100M indexed rows

I have this mysql table: CREATE TABLE `codes` ( `code` bigint(11) unsigned NOT NULL, `allocation` int(11) NOT NULL DEFAULT '0', `used` tinyint(1) NOT NULL DEFAULT '0', PRIMARY KEY (`code`), ...
5
votes
1answer
167 views

How big of an impact does NUMA really have?

I was reading up on Non-Uniform Memory Access (NUMA) and I was wondering how much of a difference it can really make? Another way to word that, what level of throughput is required before this ...
15
votes
1answer
2k views

SQL Server - Anyone use SUMA, trace flag 8048, or trace flag 8015?

Recently included SQL Server startup Trace Flag 8048 to resolve a serious spinlock contention issue in a SQL Server 2008 R2 system. Interested to hear from others who have found usage cases where ...
1
vote
0answers
26 views

Speed of Split Database vs ODBC with SQL Server vs ODBC with Azure Cloud

I would like to be able to host my data either in the cloud or in SQL Server, as having all my data in one Access file just doesn't seem the most secure to me (or am I wrong?). My forms contain many ...
1
vote
1answer
528 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
votes
1answer
32 views

Creating index for large table is taking forever

I am trying to create Index for a large table with row count of 496,000,000 and the database is on SQL Server 2012 Enterprise edition. I know how to create index but its taking forever and would like ...
3
votes
0answers
63 views

Creating MSSQL Performance Baseline Monitoring

In order to get an overview and compareable data my current task is to create a performance baseline to get some figures about the different productive sql instances. My thoughts are: I want to ...
0
votes
0answers
41 views

Upsert - Should I verify the row exists first, attempt an update, or try to insert first?

In a software that I'm working, I have a table with a few columns and a id. In some events in my software, I need to update some column of a record with a certain unique field (other column), but ...
1
vote
1answer
29 views

Things to keep in mind while editing Mysql “my.cnf” file

Today I tried to boost mysql's(installed in my system Ubuntu 14.04) performance as I have many sites(PHP/Magento) installed in my system which relies on mysql as database server, but when I edited the ...
2
votes
1answer
174 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 ...
0
votes
1answer
141 views

Large long-running reporting queries are causing very slow new mysql connections

Usually, mysql's connecton time is in the 0.001 second range. However, when I run a large reporting query (that spans multiple tables with aggregates), I get tons of warnings saying that new mysql ...
0
votes
2answers
43 views

Identical SQL Server databases hosted in the same physical DB server

We have hosted similar SQL Server 2014 databases TestDB and TESTDB_Copy on the same physical server. The two databases are almost the same and there may be minor differences in the number of records ...
3
votes
1answer
174 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 ...
0
votes
1answer
169 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.
5
votes
2answers
499 views

If I update a column record in a table, will indexes that do NOT have this column in it be affected?

In terms of performance if I have a table like so: CREATE TABLE [TESTDATA].[TableA]( [Col1] [nchar](5) NOT NULL, [Col2] [nchar](2) NULL, [Col3] [float] NULL CONSTRAINT [TableA_PK] PRIMARY ...
6
votes
2answers
261 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 ...
0
votes
3answers
211 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
1answer
89 views

Increase SQL Server Performance

I have a fairly simple SQL Server 2014 Standard database with one main table. Here's the workload: I insert a row, do a few updates to it (up to 5 updates), and move on. I always update recent rows. ...
3
votes
2answers
332 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 ...
1
vote
1answer
478 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 ...
2
votes
1answer
48 views

Performance of bitwise operators on byte column vs individual bit columns

I'm designing a database schema at the moment, but have a performance query. Our table needs to have (at least) two flags, or boolean values. We can call these IsComplete and IsExportable. The ...