Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>A connection pool helps mitigating the overhead/cost of creating new connections to the database, by reusing already existing ones. This is important if your workload requires many, short to medium living connections, e.g. an app that processes concurrent user requests by querying the database. Unfortunately your example benchmark code does not have such a profile. You are just using 4 connections in parallel and there is no reuse involved.</p> <p>What a connection pool <strong>cannot</strong> achieve is magically speeding up execution times or improving the concurrency level beyond that, which is provided by the database. If the benchmark code represents the expected workload, I would advise you to look into batching statements instead of threading. That will massively increase performance of INSERT/UPDATE operations.</p> <p><em>update</em> :</p> <p>Using multiple connections in parallel <em>can</em> enhance performance. Just keep in mind, that there is not necessarily a relation between multiple threads in your Java application and in the database. JDBC is just a wrapper around the database driver, using multiple connections results in multiple queries being submitted to the database server in parallel. If those queries are suited for it, every modern RDBMS will be able to process them in parallel. But if those queries are very work intensive, or even worse include table locks or conflicting updates, the DB may not be able to do so. If you experience bad performance, check which queries are lagging and optimize them (are they efficient? proper indexes in place? denormalizing the schema may help in more extreme cases. Use prepared statements and batch mode for larger updates, etc.). If your db is overloaded with many, similar and small queries, consider caching frequently used data.</p>
    singulars
    1. This table or related slice is empty.
    1. POJava MySQL JDBC Slow/Taking turns
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USPyranja
    1. USPyranja
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POJava MySQL JDBC Slow/Taking turns
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COSurely there is a way to open multiple connections and use them simultaneously though?
      singulars
      1. PO
      1. USTimothy Hanes
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload