Hi,
For WinGetFuncArgInFrame():
+ if (winobj->null_treatment == NULL_TREATMENT_IGNORE)
{
...
+ if (target > 0)
+ step = 1;
+ else if (target < 0)
+ step = -1;
+ else if (seektype == WINDOW_SEEK_HEAD)
+ step = 1;
+ else if (seektype == WINDOW_SEEK_TAIL)
+ step = -1;
+ else
+ step = 0;
...
+ relpos = 0;
+ }
Why is relpos always set to 0 ?
In similar code in WinGetFuncArgInPartition(), I saw the following:
+ if (target > 0)
+ step = 1;
+ else if (target < 0)
+ step = -1;
+ else
+ step = 0;
+ relpos = step;
Maybe add a comment above the relpos assignment.
Thanks
Hi, the building warning below is fixed now, no other changes. Also, I can confirm that the corner case with offset=0 in lead and lag works correctly.
gcc -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Werror=vla -Wendif-labels -Wmissing-format-attribute -Wimplicit-fallthrough=3 -Wcast-function-type -Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard -Wno-format-truncation -Wno-stringop-truncation -O2 -I../../../src/include -I/home/krasiyan/pgsql/postgresql/src/include -D_GNU_SOURCE -I/usr/include/libxml2 -c -o nodeWindowAgg.o /home/krasiyan/pgsql/postgresql/src/backend/executor/nodeWindowAgg.c
/home/krasiyan/pgsql/postgresql/src/backend/executor/nodeWindowAgg.c: In function ‘WinGetFuncArgInPartition’:
/home/krasiyan/pgsql/postgresql/src/backend/executor/nodeWindowAgg.c:3274:10: warning: ‘step’ may be used uninitialized in this function [-Wmaybe-uninitialized]
3274 | relpos += step;
| ~~~~~~~^~~~~~~
/home/krasiyan/pgsql/postgresql/src/backend/executor/nodeWindowAgg.c: In function ‘WinGetFuncArgInFrame’:
/home/krasiyan/pgsql/postgresql/src/backend/executor/nodeWindowAgg.c:3531:10: warning: ‘step’ may be used uninitialized in this function [-Wmaybe-uninitialized]
3531 | relpos += step;
| ~~~~~~~^~~~~~~
On 1/1/21 10:21 PM, Zhihong Yu wrote:
> Krasiyan:
> Happy New Year.
>
> For WinGetFuncArgInPartition():
>
> + if (target > 0)
> + step = 1;
> + else if (target < 0)
> + step = -1;
> + else
> + step = 0;
>
> When would the last else statement execute ? Since the above code is
> for WINDOW_SEEK_CURRENT, I wonder why step should be 0.
Hi.
"lag(expr, 0) over w" is useless but valid.
--
Vik Fearing
