database/sqlite
1
0
Fork 0
mirror of https://github.com/sqlite/sqlite.git synced 2025-08-08 14:02:16 +03:00
Code Activity

Optimize the IS NULL and IS NOT NULL operators so that they avoid loading

Browse Source 
large strings or blobs off of disk if all it needs to know is whether or
not the string or blob is NULL.

FossilOrigin-Name: cb94350185f555c333b628ee846c47bcc9df5f76bb82de569b8322f30dbbe1bc
This commit is contained in:
drh
2022-10-13 15:09:44 +00:00
parent 7ca4af6a9f eddfa9840e
commit 921acff927
7 changed files with 34 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
src/vdbe.c
View File

@@ -2781,10 +2781,12 @@ case OP_Offset: { /* out3 */
** if the P4 argument is a P4_MEM use the value of the P4 argument as
** the result.
**
** If the OPFLAG_LENGTHARG and OPFLAG_TYPEOFARG bits are set on P5 then
** the result is guaranteed to only be used as the argument of a length()
** or typeof() function, respectively. The loading of large blobs can be
** skipped for length() and all content loading can be skipped for typeof().
** If the OPFLAG_LENGTHARG bit is set in P5 then the result is guaranteed
** to only be used by the length() function or the equivalent. The content
** of large blobs is not loaded, thus saving CPU cycles. If the
** OPFLAG_TYPEOFARG bit is set then the result will only be used by the
** typeof() function or the IS NULL or IS NOT NULL operators or the
** equivalent. In this case, all content loading can be omitted.
*/
case OP_Column: {
u32 p2; /* column number to retrieve */