refactor: increase the buffer for each agg operator, and make the pointer...

refactor: increase the buffer for each agg operator, and make the pointer attributes in SColumnInfoData to be aligned to 8bit in memory to speedup the execution of memmove & memset.

include/common/tcommon.h

@@ -225,13 +225,13 @@ typedef struct SVarColAttr {
 // pBlockAgg->numOfNull == info.rows, all data are null
 // pBlockAgg->numOfNull == 0, no data are null.
 typedef struct SColumnInfoData {
-  SColumnInfo info;     // column info
-  bool        hasNull;  // if current column data has null value.
   char*         pData;    // the corresponding block data in memory
   union {
     char*       nullbitmap;  // bitmap, one bit for each item in the list
     SVarColAttr varmeta;
   };
+  SColumnInfo info;     // column info
+  bool        hasNull;  // if current column data has null value.
 } SColumnInfoData;
 
 typedef struct SQueryTableDataCond {

source/libs/executor/src/executorimpl.c

@@ -2783,8 +2783,10 @@ int32_t getBufferPgSize(int32_t rowSize, uint32_t* defaultPgsz, uint32_t* defaul
     *defaultPgsz <<= 1u;
   }
 
+  // The default buffer for each operator in query is 10MB.
   // at least four pages need to be in buffer
-  *defaultBufsz = 4096 * 256;
+  // TODO: make this variable to be configurable.
+  *defaultBufsz = 4096 * 2560;
   if ((*defaultBufsz) <= (*defaultPgsz)) {
     (*defaultBufsz) = (*defaultPgsz) * 4;
   }