Skip to main content

Synchronous notification explained

Hi all,

it seems that my coined feature name "synchronous notification" is confusing everybody. I hope to explain it better now.

Synchronous notification is the name I gave to Npgsql implementation of Listen/Notify support where you (the Npgsql client) receive a notification message "synchronously" or "almost" at same time the notification is sent from server. This contrasts to what Npgsql had before: the client would just receive any notification on next iteration with server as this was when we processed the notification server sent us.

One possible solution for this problem before was the client to keep "polling" the server with empty commands in order to force an interation with server and receive the notification. Now, behind the scenes, Npgsql creates a new thread which keeps polling server for you with Socket.Poll() method while client is idle. This way, as soon as notification arrives in Npgsql socket, it can promptly process notification and deliver it to client with no intervention of client as before. This will help very much client applications which just stays there and wants to receive notifications from server without any modification.

It is disabled by default. You can enable it by specifying SyncNotification=true in your connection string.

I hope this explanation helps clear what is this feature of Npgsql :)


Please, share what you think about this feature and if it is working for you like it should.

Comments

Anonymous said…
wow gold | world of warcraft gold | wow power leveling | Cheap WoW Gold | Cheapest WoW Gold | Buy Cheap WoW Gold | cheapest wow gold | Buy WoW Gold | sell wow gold | WoW Accounts | wow accounts for sale | Buy WoW Power Leveling | Wow Honor Leveling | WoW profession leveling | WoW Reputation Leveling | WoW CD Key | WOW EU Gold | Cheap WoW Gold | wow gold for sale | Cheap WoW Power Leveling | WoW EU Accounts | world of warcraft accounts for sale | WoW EU CD Key | Lineage 2 Adena | Buy L2 Adena | Lineage 2 Adena for sale | Lineage 2 Accounts | Lineage 2 Power Leveling | Lineage 2 CD Key | Warhammer gold | Buy Warhammer Gold | Warhammer US Gold | Warhammer Power leveling | Warhammer CD Key | Warhammer Accounts | Warhammer EU Gold | Buy Cheap Warhammer Gold | WAR EU Gold | Buy Warhammer Power Leveling | Warhammer Online Accounts | Warhammer EU CD key | Aion gold | fast delivery Aion Gold | Aion Accounts | Aion Power Leveling | Aion CD Key | runes of magic gold | cheap runes of magic gold | runes of magic accounts | runes of magic power leveling | runes of magic cd key | runes of magic online gold | buy runes of magic eu gold | wow cheats | rom power leveling | runes of magic eu accounts for sale | cheap runes of magic cd key | FFXI Gil | Cheap FFXI Gil | Final Fantasy XI Gil | FFXI Power Leveling | FFXI CD Key | LoTRO Gold | Cheap Lotro Gold | LoTRO US Gold | LoTRO Accounts | Lotro accounts for sale | LoTRO Power Leveling | LoTRO CD Key | LoTRO EU Gold | Lord of the Rings Gold | LoTRO EU Accounts | Lotro Leveling | Lord of the Rings CD Key | Age of Conan gold | AoC US Gold | Cheap AoC Gold | Age of Conan Accounts | Age of Conan Power Leveling | Age of Conan Crafting Leveling | Age of Conan CD Key | Age of Conan EU Gold | Age of Conan Gold For Sale | Age of Conan Leveling | Age of Conan Accounts For Sale | AoC CD Key | The Chronicles of Spellborn Gold | Chronicles of Spellborn Gold | Chronicles of Spellborn Accounts | Chronicles of Spellborn Power Leveling | Chronicles of Spellborn CD key | atlantica gold | buy atlantica gold | atlantica power leveling | atlantica cd key | darkfall gold | buy darkfall gold | darkfall accounts | darkfall power leveling | darkfall cd key | silkroad gold | silkroad online gold | cheap silkroad gold | silkroad power leveling | Maple Story Mesos | Buy Maplestory Mesos | Maple Story Power Leveling | EVE ISK | EVE Online ISK | Cheap EVE ISK | EVE Power Leveling | EVE CD Key | EverQuest 2 Platinum | EverQuest 2 Gold | EQ2 Gold | EverQuest 2 Accounts | EverQuest 2 Power Leveling | EverQuest 2 CD Key
23 February, 2009 06:45
Post a Comment

Popular posts from this blog

Npgsql Tips: Using " in (...)" queries with parameters list and "any" operator

Hi, all! We have received some users questions about how to send a list of values to be used in queries using the "in" operator. Something like: select foo, bar from table where foo in (blah1, blah2, blah3); Npgsql supports array-like parameter values and the first idea to have this working would try to use it directly: NpgsqlCommand command = new NpgsqlCommand("select * from tablee where field_serial in (:parameterlist)", conn); ArrayList l = new ArrayList(); l.Add(5); l.Add(6); command.Parameters.Add(new NpgsqlParameter("parameterlist", NpgsqlDbType.Array | NpgsqlDbType.Integer)); command.Parameters[0].Value = l.ToArray(); NpgsqlDataReader dr = command.ExecuteReader(); but unfortunately this won't work as expected. Npgsql will send a query like this: select * from tablee where field_serial in ((array[5,6])::int4[]) And Postgresql will complain with the followin...
45 comments
Read more

Fixed! LOG: unexpected EOF on client connection

Hi all! Since we implemented connection pool in Npgsql, we received some complaints about EOF log messages being generated on Postgresql logs when using Npgsql. This was caused by Npgsql not sending the proper terminate message to Postgresql on pooled connections when the application terminated or more specifically when the assembly was unloaded. This is a long time problem with Npgsql connection pool. I even talked about it in the past . Up to now, I had no idea about how to fix that as I wasn't able to close the connections in the pool. When I tried to put a finalizer in NpgsqlConnectorPool, which would be triggered when the assembly was unloaded, I received object already disposed exceptions when trying to send something to the stream. That's when I came up with the "excellent" idea of subclassing the networkstream class and override its Dispose method so that I could send the postgresql terminate message before it was disposed! :) It worked like a charm! ...
5 comments
Read more

Npgsql 2.2.0 final release is out!

This is Npgsql 2.2.0 Final Release This release contains 249 commits since the last stable release. Includes bug fixes, improvements and new features. Update notice: If you have been using Npgsql 2.2.0-rc2, you don't need to update to this version. They are the same except for the Assembly version information. Major highlights Visual Studio DDEX support   Kenji Uno added support for DDEX. Now you can use Npgsql with Visual Studio data designer. This is a missing feature a lot of our users requested in the past. Kenji added a tutorial about how to use Npgsql with DDEX. You can find it here: https://github.com/npgsql/Npgsql/wiki/Visual-Studio-Design-Time-Support---DDEX-Provider#install-npgsqlddexprovidervsix   Entity Framework   David Karlaš added support for EFMigration and Database creation in EF6+. Now it is possible to start Code First projects without needing to create a database upfront. EntityFramework and Npgsql will take care of it. E...
15 comments
Read more