Hi Jay, Sorry, that email got sent prematurely. I had meant to save it as a draft but instead it got sent. :(
Hopefully I can push up what I have today and resend the correct email. Some of what I wrote in that email is already out of date. Barry On 4/23/10 10:55 AM, "Jay Pipes" <[email protected]> wrote: > Hi Barry! I can't find your branch on Launchpad.net. Could you post > the link to it? > > Thanks! > > jay > > On Thu, Apr 22, 2010 at 11:27 PM, Barry Leslie > <[email protected]> wrote: >> Hi, >> >> I am working on a low level events plugin. The idea is that this API can be >> used to implement other plugins which are interested in observing different >> database events and doing something with the information. >> >> There are 3 type of events: "Session Events", "Schema Events", and "Table >> Events". The plugins can register which events they are interested in and >> then they will be notified of only the events they are interested in. >> >> New plugin events can be added as people have need of them, currently I have >> added the events I need for the PBMS daemon: >> >> /* Schema events: */ >> PRE_DROP_TABLE, POST_DROP_TABLE, >> PRE_RENAME_TABLE, POST_RENAME_TABLE, >> >> /* Table events: */ >> PRE_WRITE_ROW, POST_WRITE_ROW, >> PRE_UPDATE_ROW, POST_UPDATE_ROW, >> PRE_DELETE_ROW, POST_DELETE_ROW, >> >> /* Session events: */ >> PRE_CREATE_DATABASE, POST_CREATE_DATABASE, >> PRE_DROP_DATABASE, POST_DROP_DATABASE, >> >> Table events are specific to a table so in he case of PBMS I can say I am >> interested in table events that occur only on tables that contain BLOB >> columns and I can specify exactly which events I am interested in. >> >> Schema events are events that occur with in a specific database. So a plugin >> can tell drizzle that it is only interested in schema events that occur on >> database 'XYZ'. >> >> Session events are events that occur out side of the context of a database >> or table. It would be possible for example to only track session events for >> specific users. >> >> For any one event drizzle only calls the event observers that have >> registered an interest in that event. So if no plugins have registered an >> interest in an event nothing is done. >> >> The event handlers are specific to each event, passing in what ever >> information is relevant to that event. There is NO generic event handler. >> >> The 'PRE' events may allow data modification depending on the type of event. >> If a 'PRE' event handler fails then the action will be aborted. "POST" event >> handlers are ReadOny and cannot modify the data, they are also not allowed >> to fail, or if they do it will have no effect on the operation. >> >> I have pushed up the branch "drizzle_events" containing my new plugin API. >> The main points of interest are: >> >> drizzled/plugin/event.h >> drizzled/plugin/event.cc >> >> You can look in drizzled/table_share.h and drizzled/session.h to see how the >> events of interest are registered with the table, schema. or session. >> >> You will find some example event points in: >> drizzled/cursor.cc >> drizzled/plugin/storage_engine.cc >> drizzled/statement/create_schema.cc >> drizzled/statement/drop_schema.cc >> >> I have also created an example pluggin that observes some events and prints >> them out as they occur. >> >> plugin/hello_events >> >> So I will just put on my flame proof suit and wait for people's comments and >> suggestions. :) >> >> Barry >> >> >> ------------------------------------------------------------------------- >> Barry Leslie >> >> SNAP Innovation Softwareentwicklung GmbH >> Senior Software Engineer >> >> Tel: (001) 250 884 1820 >> Fax: (001) 250 595 4460 >> Email: [email protected] >> Web: www.PrimeBase.com >> >> SNAP Innovation Softwareentwicklung GmbH, D-22765 Hamburg, >> Max-Brauer-Allee 50, Germany >> Amtsgericht Hamburg HRB 61066, Geschäftsführer: Ulrich Zimmer, Paul >> McCullagh >> ------------------------------------------------------------------------- >> >> >> >> >> _______________________________________________ >> Mailing list: https://launchpad.net/~drizzle-discuss >> Post to : [email protected] >> Unsubscribe : https://launchpad.net/~drizzle-discuss >> More help : https://help.launchpad.net/ListHelp >> ------------------------------------------------------------------------- Barry Leslie SNAP Innovation Softwareentwicklung GmbH Senior Software Engineer Tel: (001) 250 884 1820 Fax: (001) 250 595 4460 Email: [email protected] Web: www.PrimeBase.com SNAP Innovation Softwareentwicklung GmbH, D-22765 Hamburg, Max-Brauer-Allee 50, Germany Amtsgericht Hamburg HRB 61066, Geschäftsführer: Ulrich Zimmer, Paul McCullagh ------------------------------------------------------------------------- _______________________________________________ Mailing list: https://launchpad.net/~drizzle-discuss Post to : [email protected] Unsubscribe : https://launchpad.net/~drizzle-discuss More help : https://help.launchpad.net/ListHelp
