diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/indexam.sgml | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/doc/src/sgml/indexam.sgml b/doc/src/sgml/indexam.sgml index dc7d14b60dd..d17fcbd5cec 100644 --- a/doc/src/sgml/indexam.sgml +++ b/doc/src/sgml/indexam.sgml @@ -164,6 +164,10 @@ typedef struct IndexAmRoutine amestimateparallelscan_function amestimateparallelscan; /* can be NULL */ aminitparallelscan_function aminitparallelscan; /* can be NULL */ amparallelrescan_function amparallelrescan; /* can be NULL */ + + /* interface functions to support planning */ + amtranslate_strategy_function amtranslatestrategy; /* can be NULL */ + amtranslate_cmptype_function amtranslatecmptype; /* can be NULL */ } IndexAmRoutine; </programlisting> </para> @@ -876,6 +880,28 @@ amparallelrescan (IndexScanDesc scan); the beginning. </para> + <para> +<programlisting> +CompareType +amtranslatestrategy (StrategyNumber strategy, Oid opfamily, Oid opcintype); + +StrategyNumber +amtranslatecmptype (CompareType cmptype, Oid opfamily, Oid opcintype); +</programlisting> + These functions, if implemented, will be called by the planer and executor + to convert between fixed <type>CompareType</type> values and the specific + strategy numbers used by the access method. These functions can be + implemented by access methods that implement functionality similar to the + built-in btree or hash access methods, and by implementing these + translations, the system can learn about the semantics of the access + method's operations and can use them in place of btree or hash indexes in + various places. If the functionality of the access method is not similar + to those built-in access methods, these functions do not need to be + implemented. If the functions are not implemented, the access method will + be ignored for certain planner and executor decisions, but is otherwise + fully functional. + </para> + </sect1> <sect1 id="index-scanning"> |