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typedef struct WindowAggState
{
ScanState ss; /* its first field is NodeTag */
/* these fields are filled in by ExecInitExpr: */
List *funcs; /* all WindowFunc nodes in targetlist */
int numfuncs; /* total number of window functions */
int numaggs; /* number that are plain aggregates */
WindowStatePerFunc perfunc; /* per-window-function information */
WindowStatePerAgg peragg; /* per-plain-aggregate information */
ExprState *partEqfunction; /* equality funcs for partition columns */
ExprState *ordEqfunction; /* equality funcs for ordering columns */
Tuplestorestate *buffer; /* stores rows of current partition */
int current_ptr; /* read pointer # for current row */
int framehead_ptr; /* read pointer # for frame head, if used */
int frametail_ptr; /* read pointer # for frame tail, if used */
int grouptail_ptr; /* read pointer # for group tail, if used */
int64 spooled_rows; /* total # of rows in buffer */
int64 currentpos; /* position of current row in partition */
int64 frameheadpos; /* current frame head position */
int64 frametailpos; /* current frame tail position (frame end+1) */
/* use struct pointer to avoid including windowapi.h here */
struct WindowObjectData *agg_winobj; /* winobj for aggregate fetches */
int64 aggregatedbase; /* start row for current aggregates */
int64 aggregatedupto; /* rows before this one are aggregated */
int frameOptions; /* frame_clause options, see WindowDef */
ExprState *startOffset; /* expression for starting bound offset */
ExprState *endOffset; /* expression for ending bound offset */
Datum startOffsetValue; /* result of startOffset evaluation */
Datum endOffsetValue; /* result of endOffset evaluation */
/* these fields are used with RANGE offset PRECEDING/FOLLOWING: */
FmgrInfo startInRangeFunc; /* in_range function for startOffset */
FmgrInfo endInRangeFunc; /* in_range function for endOffset */
Oid inRangeColl; /* collation for in_range tests */
bool inRangeAsc; /* use ASC sort order for in_range tests? */
bool inRangeNullsFirst; /* nulls sort first for in_range tests? */
/* these fields are used in GROUPS mode: */
int64 currentgroup; /* peer group # of current row in partition */
int64 frameheadgroup; /* peer group # of frame head row */
int64 frametailgroup; /* peer group # of frame tail row */
int64 groupheadpos; /* current row's peer group head position */
int64 grouptailpos; /* " " " " tail position (group end+1) */
MemoryContext partcontext; /* context for partition-lifespan data */
MemoryContext aggcontext; /* shared context for aggregate working data */
MemoryContext curaggcontext; /* current aggregate's working data */
ExprContext *tmpcontext; /* short-term evaluation context */
bool all_first; /* true if the scan is starting */
bool all_done; /* true if the scan is finished */
bool partition_spooled; /* true if all tuples in current partition
* have been spooled into tuplestore */
bool more_partitions; /* true if there's more partitions after
* this one */
bool framehead_valid; /* true if frameheadpos is known up to
* date for current row */
bool frametail_valid; /* true if frametailpos is known up to
* date for current row */
bool grouptail_valid; /* true if grouptailpos is known up to
* date for current row */
TupleTableSlot *first_part_slot; /* first tuple of current or next
* partition */
TupleTableSlot *framehead_slot; /* first tuple of current frame */
TupleTableSlot *frametail_slot; /* first tuple after current frame */
/* temporary slots for tuples fetched back from tuplestore */
TupleTableSlot *agg_row_slot;
TupleTableSlot *temp_slot_1;
TupleTableSlot *temp_slot_2;
bool first_run;
Datum *p;
int count;
} WindowAggState;
makenode解释
stmt = makeNode(PlannedStmt);
#define makeNode(_type_) ((_type_ *) newNode(sizeof(_type_),T_##_type_))
##表示连接符号哦
#define newNode(size, tag) \
( \
AssertMacro((size) >= sizeof(Node)), /* need the tag, at least */ \
newNodeMacroHolder = (Node *) palloc0fast(size), \
newNodeMacroHolder->type = (tag), \
newNodeMacroHolder \
)
这个宏定义是一个逗号表达式，学着点啊