doublesampleRatio;// data block sample ratio, 1 by default
SIntervalinterval;// if the upstream is an interval operator, the interval info is also kept here to get the time window to check if current data block needs to be loaded.
SArray*pGroupCols;
SArray*pGroupColVals;// current group column values, SArray<SGroupKeys>
char*keyBuf;// group by keys for hash
int32_tgroupKeyLen;// total group by column width
SHashObj*pGroupSet;// quick locate the window object for each result