Vander Clock Stephane <svandercl...@yahoo.fr> wrote: >>> Some pragma are set be connection, >>> some by database (and all the connection to this database) and >>> some by the engine (all database and all connections) >> Could you give an example of this last category? I don't see by what >> possible mechanism could a PRAGMA issued in one process >> connected to one database file, affect a separate process connected to a >> different database file. Einstein's spooky action at a >> distance? > > for exemple page_size, encoding, auto_vaccum, legacy_file_format
Those are of the second category - they affect one database file that is created by the connection on which the pragma is issued. If you then create another connection and another file, it won't be affected by these pragmas (unless you issue them on the new connection, too). > From the doc : > *PRAGMA secure_delete; > *When there are attached databases and no database is specified in the > pragma, all databases have their secure-delete setting altered > The secure-delete setting for newly attached databases is the setting of > the main database at the time the ATTACH command is evaluated > > so doing this pragma will change the behavior of all the database All the databases ATTACHed to the current connection. Not all the databases in existence. This setting is per connection. Even if you open another connection to the same database, it won't have the same behavior. > and by > the way all the connections ... Where do you get that from? >>> so how to distinguish the pragma that must be call on every connection >>> or just set one time after the DLL initialization ? >> >> I'm not aware of any pragmas that could be set once and somehow magically >> take effect on all subsequent connections. How would >> you even set such a pragma? You need a connection to run PRAGMA statements. > > like page_size, encoding, auto_vaccum, legacy_file_format, secure_delete > for exemple ? Those don't behave the way you seem to think they do. In any case, the documentation describes their behavior very carefully and precisely. > for exemple what about > cache_size when we use the Share_Cache mode ? This does seem to be an omission in the documentation. It's not entirely clear how cache_size interacts with shared cache. > so can you confirm me that what i do is good : > > at the initialization : > sqlite3_config(SQLITE_CONFIG_MULTITHREAD); > sqlite3_initialize; > sqlite3_enable_shared_cache(1); > > after before creating any database i do : > > PRAGMA page_size = 512 > PRAGMA encoding = "UTF-8 > PRAGMA legacy_file_format = 0 > PRAGMA auto_vacuum = NONE > > after for "EVERY" new connection on the database(s) i do : > > PRAGMA cache_size = 2000 > PRAGMA count_changes = 0 > PRAGMA journal_mode = MEMORY > PRAGMA journal_size_limit = -1 > PRAGMA locking_mode = NORMAL > PRAGMA read_uncommitted = 1 > PRAGMA secure_delete = 0 > PRAGMA synchronous = OFF > PRAGMA temp_store = MEMORY Looks right to me. -- Igor Tandetnik _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
