/ Check-in [f474aeac]

 ```73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 ``` ``` x=y1 OR x=y2 This is the INDEX_NOOP optimization and is only undertaken if the IN operator is used for membership testing. If the IN operator is driving a loop, then skip this step entirely. 2. Check the LHS to see if it is a partial-NULL and if it is, jump ahead to step 4. 3. Do a binary search for the RHS using the LHS as a probe. If an exact match is found, return TRUE. 4. If we do not need to distingish between FALSE and NULL, then return FALSE. 5. If the RHS is non-NULL then return FALSE. 6. For each row in the RHS, compare that row against the LHS and if the result is NULL, immediately return NULL. In the case of a scalar IN operator, we only need to look at the very first row the RHS because for a scalar RHS, all NULLs will always come first. If the RHS is empty, this step is a no-op. 7. Return FALSE. ``` ``` | | < | > | | ``` ```73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 ``` ``` x=y1 OR x=y2 This is the INDEX_NOOP optimization and is only undertaken if the IN operator is used for membership testing. If the IN operator is driving a loop, then skip this step entirely. 2. Check the LHS to see if it is a partial-NULL and if it is, jump ahead to step 5. 3. Do a binary search of the RHS using the LHS as a probe. If an exact match is found, return TRUE. 4. If the RHS is non-NULL then return FALSE. 5. If we do not need to distingish between FALSE and NULL, then return FALSE. 6. For each row in the RHS, compare that row against the LHS and if the result is NULL, immediately return NULL. In the case of a scalar IN operator, we only need to look at the very first row the RHS because for a scalar RHS, all NULLs will always come first. If the RHS is empty, this step is a no-op. 7. Return FALSE. ```