DNS server cache

Discussion of open issues, suggestions and bugs regarding ADO.NET provider for Oracle
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Joined: Tue 01 Jul 2014 12:34

DNS server cache

Post by andreypl » Tue 01 Jul 2014 12:42


We are using dotConnect for Oracle version 6.30 with entity framework. Recently we had a production problem with our application the same time that on if DNS servers in our organization was down for maintenance. Our system administrator discovered that the application servers execute a DNS resolve request each time a request to thee database is made and they say that the local server cache of DNS records is not used by devart at all.

We used network monitor and we saw that indeed a request for DNS resolution is made each time. Other severs which do not host applications that use devart to connect to the database use the cache and do not request dns resolution each time.

Are you familiar with this issue ? It is causing a major load on DNS server and our other systems

Devart Team
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Re: DNS server cache

Post by Pinturiccio » Wed 02 Jul 2014 15:22

dotConnect for Oracle supports two connection modes:
1. OCI connection mode. In this mode connection parameters are passed to Oracle Client and then it establishes a connection. You may ask Oracle support for more detailed information on how Oracle Client uses DNS server and its cache.
2. Direct connection mode. This mode allows connecting without using Oracle Client. In this mode dotConnect for Oracle opens a socket. All the subsequent operations related to establishing a connection are performed by the operating system. Windows settings determine interaction with a DNS server.

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