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Questions tagged [database-performance]

Questions about database performance and tuning, ranging from files organization and configuration to benchmarking and system optimization, passing through management systems and the fastest ways to operate a database.

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How big can a MySQL database get before performance starts to degrade

At what point does a MySQL database start to lose performance? Does physical database size matter? Do number of records matter? Is any performance degradation linear or exponential? I have what I believe to be a large database, with roughly 15M…
Grant
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Using git repository as a database backend

I'm doing a project that deals with structured document database. I have a tree of categories (~1000 categories, up to ~50 categories on each level), each category contains several thousands (up to, say, ~10000) of structured documents. Each…
GreyCat
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How to configure MongoDB Java driver MongoOptions for production use?

I've been searching the web looking for best practices for configuring MongoOptions for the MongoDB Java driver and I haven't come up with much other than the API. This search started after I ran into the "com.mongodb.DBPortPool$SemaphoresOut: Out…
Dan Polites
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LOWER LIKE vs iLIKE

How does the performance of the following two query components compare? LOWER LIKE ... LOWER(description) LIKE '%abcde%' ... iLIKE ... description iLIKE '%abcde%' ...
user664833
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Entity Framework Vs Stored Procedures - Performance Measure

I'm trying to establish how much slower Entity Framework is over Stored Procedures. I hope to convince my boss to let us use Entity Framework for ease of development. Problem is I ran a performance test and it looks like EF is about 7 times slower…
reach4thelasers
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How many columns is too many columns?

I've noticed that a lot of folks here cite tables with 20+ (I've seen as much as 55) columns in one table. Now I don't pretend to be a database design expert, but I've always heard that this is a horrible practice. When I see this, I usually…
Stephen Collins
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Postgresql Truncation speed

We're using Postgresql 9.1.4 as our db server. I've been trying to speed up my test suite so I've stared profiling the db a bit to see exactly what's going on. We are using database_cleaner to truncate tables at the end of tests. YES I know…
brad
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Dropping column in Postgres on a large dataset

So I have a table with a large dataset and this table has a three columns that I would like to drop. The question is: how will Postgres deal with it? Will it walk through every entry or will it just update mapping info without much overhead? Can I…
nikita2206
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How do NULL values affect performance in a database search?

In our product we have a generic search engine, and trying to optimze the search performance. A lot of the tables used in the queries allow null values. Should we redesign our table to disallow null values for optimization or not? Our product runs…
Jakob Ojvind Nielsen
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Database partitioning - Horizontal vs Vertical - Difference between Normalization and Row Splitting?

I am trying to grasp the different concepts of Database Partitioning and this is what I understood of it: Horizontal Partitioning/Sharding: Splitting a table into different table that will contain a subset of the rows that were in the initial table…
dukable
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MySQL Partitioning / Sharding / Splitting - which way to go?

We have an InnoDB database that is about 70 GB and we expect it to grow to several hundred GB in the next 2 to 3 years. About 60 % of the data belong to a single table. Currently the database is working quite well as we have a server with 64 GB of…
sme
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Mysql count performance on very big tables

I have a table with more than 100 millions rows in Innodb. I have to know if there is more than 5000 rows where the foreign key = 1. I don't need the exact number. I made some testing : SELECT COUNT(*) FROM table WHERE fk = 1 => 16 seconds SELECT…
hotips
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Performance difference between UUID, CHAR, and VARCHAR in PostgreSql table?

I'm storing UUID v4 values in a PostgreSQL v9.4 table, under column "id". When I create the table, is there any difference in following write or read performance whether I define the "id" column as VARCHAR(36), CHAR(36), or UUID data type? Thanks!
Pensierinmusica
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BerkeleyDB Concurrency

What's the optimal level of concurrency that the C++ implementation of BerkeleyDB can reasonably support? How many threads can I have hammering away at the DB before throughput starts to suffer because of resource contention? I've read the manual…
Ted Dziuba
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Why do spring/hibernate read-only database transactions run slower than read-write?

I've been doing some research around the performance of read-only versus read-write database transactions. The MySQL server is remote across a slow VPN link so it's easy for me to see differences between the transaction types. This is with…
Gray
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