Hi,
I'm developing a simple virtual table module and I've found possible
misbehavior of virtual table modules when used with IN condition.
Example:
select x from y where x = 3;
calls (correctly) function xFilter of my vtab module with parameter 3,
but
select x from y where x in (3)
calls xFilter without any arguments, and vtab module is not able to apply
it's filtering rules, what results in degraded performance.
Also in (every) EXPLAIN one can see, that vFilter op is executed _before_
actually processing IN condition:
0 Trace 0 0 0 00 NULL
1 Goto 0 31 0 00 NULL
2 VOpen 0 0 0 vt 00 NULL
3 Intege 1 1 0 00 NULL
4 Intege 0 2 0 00 NULL
-- vFilter op
5 VFilte 0 29 1 00 NULL
-- IN processing
6 Noop 0 0 0 00 begin I
7 If 4 15 0 00 NULL
8 Intege 1 4 0 00 NULL
9 Null 0 3 0 00 NULL
10 OpenEp 2 1 0 ke 00 NULL
11 Null 0 6 0 00 NULL
12 Intege 3 5 0 00 NULL
13 MakeRe 5 1 6 c 00 NULL
14 IdxIns 2 6 0 00 NULL
15 VColum 0 0 6 00 y.x
16 IsNull 6 28 0 00 NULL
17 Affini 6 1 0 c 00 NULL
18 NotFou 2 28 6 1 00 end IN
19 VColum 0 0 7 00 y.x
27 Result 7 8 0 00 NULL
28 VNext 0 6 0 00 NULL
29 Close 0 0 0 00 NULL
30 Halt 0 0 0 00 NULL
31 Transa 0 0 0 00 NULL
32 Verify 0 17 0 00 NULL
33 Goto 0 2 0 00 NULL
Is this a feature or bug ?
Thanks
Sam
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