4 The storage backend implements the "low level" folder abstraction, which is
5 basically an arbitary "BLOB" containing some document. The feature is that
6 we extract "quick access" / "searchable" attributes from the document content.
8 Further it contains the "folder management" API, as named folders can be stored
9 in different databases.
10 Note: we need a way to tell where "new" folders should be created
11 Note: to sync with LDAP we need to periodically delete or archive old folders
13 Folders have associated a type (like 'calendar') which defines the query
14 attributes and serialization format.
21 - hierarchies deeper than 4 (properly filter on path in OCS)
26 System-meta-data in the blob-table or in the quick-table?
27 - master data belongs into the blob table
28 - could be regular 'NSxxx' keys to differentiate meta data from
34 OCSContext - tracking context
35 OCSFolder - represents a single folder
36 OCSFolderManager - manages folders
37 OCSFolderType - the mapping info for a specific folder-type
38 OCSFieldInfo - mapping info for one 'quick field'
39 OCSChannelManager - maintains EOAdaptorChannel objects
43 - field 'value' (eg array values for participants?)
44 - BLOB archiver/unarchiver
49 OCSFolderInfoURL - the DB URL where the folder-info table is located
50 eg: http://OGo:OGo@localhost/test/folder_info
52 OCSFolderManagerDebugEnabled - enable folder-manager debug logs
53 OCSFolderManagerSQLDebugEnabled - enable folder-manager SQL gen debug logs
55 OCSChannelManagerDebugEnabled - enable channel debug pooling logs
56 OCSChannelManagerPoolDebugEnabled - debug pool handle allocation
58 OCSChannelExpireAge - if that age in seconds is exceeded, a channel
59 will be removed from the pool
60 OCSChannelCollectionTimer - time in seconds. each n-seconds the pool will be
61 checked for channels too old
63 [PGDebugEnabled] - enable PostgreSQL adaptor debugging
71 postgresql://[user]:[password]@[host]:[port]/[dbname]/[tablename]
77 - one to recreate a quick table based on the blob table
82 - need to use http:// URLs for connect info, until generic URLs in
83 libFoundation are fixed (the parses breaks on the login/password parts)
88 Q: Why do we use two tables, we could store the quick columns in the blob?
90 They could be in the same table. We considered using separate tables since the
91 quick table is likely to be recreated now and then if BLOB indexing
93 Actually one could even use different _quick tables which share a common BLOB
95 (a quick table is nothing more than a database index and like with DB indexes
96 multiple ones for different requirements can make sense).
98 Further it might improve caching behaviour for row based caches (the quick
99 table is going to be queried much more often) - not sure whether this is
100 relevant with PostgreSQL, probably not?
102 Q: Can we use a VARCHAR primary key?
104 We asked in the postgres IRC channel and apparently the performance penalty of
105 string primary keys isn't big.
106 We could also use an 'internal' int sequence in addition (might be useful for
108 Motivation: the 'iCalendar' ID is a string and usually looks like a GUID.
110 Q: Why using VARCHAR instead of TEXT in the BLOB?
112 To quote PostgreSQL documentation:
113 "There are no performance differences between these three types, apart from
114 the increased storage size when using the blank-padded type."
115 So varchar(xx) is just a large TEXT. Since we intend to store mostly small
116 snippets of data (tiny XML fragments), we considered VARCHAR the more