User:Rkent/Folder Data Persistence: Difference between revisions
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These notes were prepared to understand proposals in bug 1032360: "nsMsgLocalMailFolder::GetSizeOnDisk seems to return wrong value for maildir store" to persistently store the folder size, but should be applicable to other issues of folder persistence. | These notes were prepared to understand proposals in bug 1032360: "nsMsgLocalMailFolder::GetSizeOnDisk seems to return wrong value for maildir store" to persistently store the folder size, but should be applicable to other issues of folder persistence. | ||
== Notes == | |||
=== Folder Cache (panacea.dat) === | |||
The folder cache file, named "panacea.dat", is a profile-wide file that contains summary information for each folder. Its main purpose is to allow the folder pane to display the folder tree and associated folder information (such as unread count) without having to open the mork summary file for each folder to get that information, which would take both excessive time and memory. The canonical source for folder metadata though is the dbFolderInfo object that is stored within the mork summary file, so this plan creates a sync issue between these files, as well as with associated memory objects owner by the folder. | |||
(The naming of panacea.dat is in nsMailDirProvider.cpp for the leaf name, but NS_APP_MESSENGER_FOLDER_CACHE_50_FILE is used to access the full path to that file). | |||
panacea.dat is accessed using nsIMsgFolderCacheElement, which uses a string key to access data for a folder. The string key is defined in nsMsgDBFolder::GetFolderCacheKey using the persistent path of the .msf mork file for the folder (for non root-folders) or the main folder (for the root folder). Examples: | |||
C:\\Users\\Kent\\AppData\\Roaming\\Thunderbird\\Profiles\\3gtxygma.default\\ImapMail\\mail.caspia.com\\Sent.msf | |||
C:\\Users\\Kent\\AppData\\Roaming\\Thunderbird\\Profiles\\3gtxygma.default\\ImapMail\\mail.caspia.com | |||
panacea.dat is owned by nsMsgAccountManager, which has methods to acquire the folder cache object and write to it. | |||
Revision as of 18:09, 30 October 2014
Intro
The point of this page is to record notes on understanding data persistence of information associated with folders. This is complicated because the information is frequently stored in multiple in-memory objects, as well as in two different database: dbFolderInfo which is a table of the main folder message summary database, as well as panacea.dat which is a cache of the same information.
These notes were prepared to understand proposals in bug 1032360: "nsMsgLocalMailFolder::GetSizeOnDisk seems to return wrong value for maildir store" to persistently store the folder size, but should be applicable to other issues of folder persistence.
Notes
Folder Cache (panacea.dat)
The folder cache file, named "panacea.dat", is a profile-wide file that contains summary information for each folder. Its main purpose is to allow the folder pane to display the folder tree and associated folder information (such as unread count) without having to open the mork summary file for each folder to get that information, which would take both excessive time and memory. The canonical source for folder metadata though is the dbFolderInfo object that is stored within the mork summary file, so this plan creates a sync issue between these files, as well as with associated memory objects owner by the folder.
(The naming of panacea.dat is in nsMailDirProvider.cpp for the leaf name, but NS_APP_MESSENGER_FOLDER_CACHE_50_FILE is used to access the full path to that file).
panacea.dat is accessed using nsIMsgFolderCacheElement, which uses a string key to access data for a folder. The string key is defined in nsMsgDBFolder::GetFolderCacheKey using the persistent path of the .msf mork file for the folder (for non root-folders) or the main folder (for the root folder). Examples:
C:\\Users\\Kent\\AppData\\Roaming\\Thunderbird\\Profiles\\3gtxygma.default\\ImapMail\\mail.caspia.com\\Sent.msf C:\\Users\\Kent\\AppData\\Roaming\\Thunderbird\\Profiles\\3gtxygma.default\\ImapMail\\mail.caspia.com
panacea.dat is owned by nsMsgAccountManager, which has methods to acquire the folder cache object and write to it.