Movatterモバイル変換

Some functions' names were changed, for examplerank tots_rank. The replacementtsearch2 module provides aliases having the old names.

The built-in text search data types and functions all exist within the system schemapg_catalog. In an installation usingtsearch2, these objects would usually have been in thepublic schema, though some users chose to place them in a separate schema of their own. Explicitly schema-qualified references to the objects will therefore fail in either case. The replacementtsearch2 module provides alias objects that are stored inpublic (or another schema if necessary) so that such references will still work.

There is no concept of a“current parser” or“current dictionary” in the built-in text search features, only of a current search configuration (set by thedefault_text_search_config parameter). While the current parser and current dictionary were used only by functions intended for debugging, this might still pose a porting obstacle in some cases. The replacementtsearch2 module emulates these additional state variables and provides backwards-compatible functions for setting and retrieving them.

The oldtsearch2 trigger function allowed items in its argument list to be names of functions to be invoked on the text data before it was converted totsvector format. This was removed as being a security hole, since it was not possible to guarantee that the function invoked was the one intended. The recommended approach if the data must be massaged before being indexed is to write a custom trigger that does the work for itself.

Text search configuration information has been moved into core system catalogs that are noticeably different from the tables used bytsearch2. Any applications that examined or modified those tables will need adjustment.

If an application used any custom text search configurations, those will need to be set up in the core catalogs using the new text search configuration SQL commands. The replacementtsearch2 module offers a little bit of support for this by making it possible to load an old set oftsearch2 configuration tables intoPostgreSQL 8.3. (Without the module, it is not possible to load the configuration data because values in theregprocedure columns cannot be resolved to functions.) While those configuration tables won't actuallydo anything, at least their contents will be available to be consulted while setting up an equivalent custom configuration in 8.3.

The oldreset_tsearch() andget_covers() functions are not supported.

The replacementtsearch2 module does not define any alias operators, relying entirely on the built-in ones. This would only pose an issue if an application used explicitly schema-qualified operator names, which is very uncommon.