Hi, While reading the nbtree codes, I noticed that the comments on BTScanInsertData no longer describes the meaning of the nextkey and backward fields. The comment curently only says:
* See comments in _bt_first for an explanation of the nextkey and backward * fields. Detailed comments used to exit here, but they were removed by c9c0589fda0e, I guess, because the semantic changed when the optimazation for backward scans was introduced. However, having a brief, general description here is still useful for readers. I've attached a patch that adds the following comment: + * nextkey determines how the scankey's boundary is interpreted, and backward + * indicates a backward scan. See comments in _bt_first for a more detailed + * explanation of these fields. What do think? Regards, Yugo Nagata -- Yugo Nagata <[email protected]>
diff --git a/src/include/access/nbtree.h b/src/include/access/nbtree.h index 16be5c7a9c1..581e200a3cf 100644 --- a/src/include/access/nbtree.h +++ b/src/include/access/nbtree.h @@ -774,8 +774,9 @@ typedef BTStackData *BTStack; * bit, but may not when inserting into an INCLUDE index (tuple header value * is affected by the NULL-ness of both key and non-key attributes). * - * See comments in _bt_first for an explanation of the nextkey and backward - * fields. + * nextkey determines how the scankey's boundary is interpreted, and backward + * indicates a backward scan. See comments in _bt_first for a more detailed + * explanation of these fields. * * scantid is the heap TID that is used as a final tiebreaker attribute. It * is set to NULL when index scan doesn't need to find a position for a
