diff options
Diffstat (limited to 'src/backend/executor/nodeWindowAgg.c')
| -rw-r--r-- | src/backend/executor/nodeWindowAgg.c | 1056 |
1 files changed, 827 insertions, 229 deletions
diff --git a/src/backend/executor/nodeWindowAgg.c b/src/backend/executor/nodeWindowAgg.c index 0afb1c83d38..f6412576f40 100644 --- a/src/backend/executor/nodeWindowAgg.c +++ b/src/backend/executor/nodeWindowAgg.c @@ -180,10 +180,11 @@ static void begin_partition(WindowAggState *winstate); static void spool_tuples(WindowAggState *winstate, int64 pos); static void release_partition(WindowAggState *winstate); -static bool row_is_in_frame(WindowAggState *winstate, int64 pos, +static int row_is_in_frame(WindowAggState *winstate, int64 pos, TupleTableSlot *slot); -static void update_frameheadpos(WindowObject winobj, TupleTableSlot *slot); -static void update_frametailpos(WindowObject winobj, TupleTableSlot *slot); +static void update_frameheadpos(WindowAggState *winstate); +static void update_frametailpos(WindowAggState *winstate); +static void update_grouptailpos(WindowAggState *winstate); static WindowStatePerAggData *initialize_peragg(WindowAggState *winstate, WindowFunc *wfunc, @@ -683,11 +684,9 @@ eval_windowaggregates(WindowAggState *winstate) temp_slot = winstate->temp_slot_1; /* - * Currently, we support only a subset of the SQL-standard window framing - * rules. - * - * If the frame start is UNBOUNDED_PRECEDING, the window frame consists of - * a contiguous group of rows extending forward from the start of the + * If the window's frame start clause is UNBOUNDED_PRECEDING and no + * exclusion clause is specified, then the window frame consists of a + * contiguous group of rows extending forward from the start of the * partition, and rows only enter the frame, never exit it, as the current * row advances forward. This makes it possible to use an incremental * strategy for evaluating aggregates: we run the transition function for @@ -710,6 +709,11 @@ eval_windowaggregates(WindowAggState *winstate) * must perform the aggregation all over again for all tuples within the * new frame boundaries. * + * If there's any exclusion clause, then we may have to aggregate over a + * non-contiguous set of rows, so we punt and recalculate for every row. + * (For some frame end choices, it might be that the frame is always + * contiguous anyway, but that's an optimization to investigate later.) + * * In many common cases, multiple rows share the same frame and hence the * same aggregate value. (In particular, if there's no ORDER BY in a RANGE * window, then all rows are peers and so they all have window frame equal @@ -728,7 +732,7 @@ eval_windowaggregates(WindowAggState *winstate) * The frame head should never move backwards, and the code below wouldn't * cope if it did, so for safety we complain if it does. */ - update_frameheadpos(agg_winobj, temp_slot); + update_frameheadpos(winstate); if (winstate->frameheadpos < winstate->aggregatedbase) elog(ERROR, "window frame head moved backward"); @@ -737,15 +741,16 @@ eval_windowaggregates(WindowAggState *winstate) * the result values that were previously saved at the bottom of this * function. Since we don't know the current frame's end yet, this is not * possible to check for fully. But if the frame end mode is UNBOUNDED - * FOLLOWING or CURRENT ROW, and the current row lies within the previous - * row's frame, then the two frames' ends must coincide. Note that on the - * first row aggregatedbase == aggregatedupto, meaning this test must - * fail, so we don't need to check the "there was no previous row" case - * explicitly here. + * FOLLOWING or CURRENT ROW, no exclusion clause is specified, and the + * current row lies within the previous row's frame, then the two frames' + * ends must coincide. Note that on the first row aggregatedbase == + * aggregatedupto, meaning this test must fail, so we don't need to check + * the "there was no previous row" case explicitly here. */ if (winstate->aggregatedbase == winstate->frameheadpos && (winstate->frameOptions & (FRAMEOPTION_END_UNBOUNDED_FOLLOWING | FRAMEOPTION_END_CURRENT_ROW)) && + !(winstate->frameOptions & FRAMEOPTION_EXCLUSION) && winstate->aggregatedbase <= winstate->currentpos && winstate->aggregatedupto > winstate->currentpos) { @@ -766,6 +771,7 @@ eval_windowaggregates(WindowAggState *winstate) * - if we're processing the first row in the partition, or * - if the frame's head moved and we cannot use an inverse * transition function, or + * - we have an EXCLUSION clause, or * - if the new frame doesn't overlap the old one * * Note that we don't strictly need to restart in the last case, but if @@ -780,6 +786,7 @@ eval_windowaggregates(WindowAggState *winstate) if (winstate->currentpos == 0 || (winstate->aggregatedbase != winstate->frameheadpos && !OidIsValid(peraggstate->invtransfn_oid)) || + (winstate->frameOptions & FRAMEOPTION_EXCLUSION) || winstate->aggregatedupto <= winstate->frameheadpos) { peraggstate->restart = true; @@ -920,6 +927,8 @@ eval_windowaggregates(WindowAggState *winstate) */ for (;;) { + int ret; + /* Fetch next row if we didn't already */ if (TupIsNull(agg_row_slot)) { @@ -928,9 +937,15 @@ eval_windowaggregates(WindowAggState *winstate) break; /* must be end of partition */ } - /* Exit loop (for now) if not in frame */ - if (!row_is_in_frame(winstate, winstate->aggregatedupto, agg_row_slot)) + /* + * Exit loop if no more rows can be in frame. Skip aggregation if + * current row is not in frame but there might be more in the frame. + */ + ret = row_is_in_frame(winstate, winstate->aggregatedupto, agg_row_slot); + if (ret < 0) break; + if (ret == 0) + goto next_tuple; /* Set tuple context for evaluation of aggregate arguments */ winstate->tmpcontext->ecxt_outertuple = agg_row_slot; @@ -951,6 +966,7 @@ eval_windowaggregates(WindowAggState *winstate) peraggstate); } +next_tuple: /* Reset per-input-tuple context after each tuple */ ResetExprContext(winstate->tmpcontext); @@ -1061,6 +1077,7 @@ eval_windowfunction(WindowAggState *winstate, WindowStatePerFunc perfuncstate, static void begin_partition(WindowAggState *winstate) { + WindowAgg *node = (WindowAgg *) winstate->ss.ps.plan; PlanState *outerPlan = outerPlanState(winstate); int numfuncs = winstate->numfuncs; int i; @@ -1068,11 +1085,21 @@ begin_partition(WindowAggState *winstate) winstate->partition_spooled = false; winstate->framehead_valid = false; winstate->frametail_valid = false; + winstate->grouptail_valid = false; winstate->spooled_rows = 0; winstate->currentpos = 0; winstate->frameheadpos = 0; - winstate->frametailpos = -1; + winstate->frametailpos = 0; + winstate->currentgroup = 0; + winstate->frameheadgroup = 0; + winstate->frametailgroup = 0; + winstate->groupheadpos = 0; + winstate->grouptailpos = -1; /* see update_grouptailpos */ ExecClearTuple(winstate->agg_row_slot); + if (winstate->framehead_slot) + ExecClearTuple(winstate->framehead_slot); + if (winstate->frametail_slot) + ExecClearTuple(winstate->frametail_slot); /* * If this is the very first partition, we need to fetch the first input @@ -1099,7 +1126,7 @@ begin_partition(WindowAggState *winstate) /* * Set up read pointers for the tuplestore. The current pointer doesn't * need BACKWARD capability, but the per-window-function read pointers do, - * and the aggregate pointer does if frame start is movable. + * and the aggregate pointer does if we might need to restart aggregation. */ winstate->current_ptr = 0; /* read pointer 0 is pre-allocated */ @@ -1112,10 +1139,14 @@ begin_partition(WindowAggState *winstate) WindowObject agg_winobj = winstate->agg_winobj; int readptr_flags = 0; - /* If the frame head is potentially movable ... */ - if (!(winstate->frameOptions & FRAMEOPTION_START_UNBOUNDED_PRECEDING)) + /* + * If the frame head is potentially movable, or we have an EXCLUSION + * clause, we might need to restart aggregation ... + */ + if (!(winstate->frameOptions & FRAMEOPTION_START_UNBOUNDED_PRECEDING) || + (winstate->frameOptions & FRAMEOPTION_EXCLUSION)) { - /* ... create a mark pointer to track the frame head */ + /* ... so create a mark pointer to track the frame head */ agg_winobj->markptr = tuplestore_alloc_read_pointer(winstate->buffer, 0); /* and the read pointer will need BACKWARD capability */ readptr_flags |= EXEC_FLAG_BACKWARD; @@ -1150,6 +1181,44 @@ begin_partition(WindowAggState *winstate) } /* + * If we are in RANGE or GROUPS mode, then determining frame boundaries + * requires physical access to the frame endpoint rows, except in + * degenerate cases. We create read pointers to point to those rows, to + * simplify access and ensure that the tuplestore doesn't discard the + * endpoint rows prematurely. (Must match logic in update_frameheadpos + * and update_frametailpos.) + */ + winstate->framehead_ptr = winstate->frametail_ptr = -1; /* if not used */ + + if ((winstate->frameOptions & (FRAMEOPTION_RANGE | FRAMEOPTION_GROUPS)) && + node->ordNumCols != 0) + { + if (!(winstate->frameOptions & FRAMEOPTION_START_UNBOUNDED_PRECEDING)) + winstate->framehead_ptr = + tuplestore_alloc_read_pointer(winstate->buffer, 0); + if (!(winstate->frameOptions & FRAMEOPTION_END_UNBOUNDED_FOLLOWING)) + winstate->frametail_ptr = + tuplestore_alloc_read_pointer(winstate->buffer, 0); + } + + /* + * If we have an exclusion clause that requires knowing the boundaries of + * the current row's peer group, we create a read pointer to track the + * tail position of the peer group (i.e., first row of the next peer + * group). The head position does not require its own pointer because we + * maintain that as a side effect of advancing the current row. + */ + winstate->grouptail_ptr = -1; + + if ((winstate->frameOptions & (FRAMEOPTION_EXCLUDE_GROUP | + FRAMEOPTION_EXCLUDE_TIES)) && + node->ordNumCols != 0) + { + winstate->grouptail_ptr = + tuplestore_alloc_read_pointer(winstate->buffer, 0); + } + + /* * Store the first tuple into the tuplestore (it's always available now; * we either read it above, or saved it at the end of previous partition) */ @@ -1275,119 +1344,127 @@ release_partition(WindowAggState *winstate) * The caller must have already determined that the row is in the partition * and fetched it into a slot. This function just encapsulates the framing * rules. + * + * Returns: + * -1, if the row is out of frame and no succeeding rows can be in frame + * 0, if the row is out of frame but succeeding rows might be in frame + * 1, if the row is in frame + * + * May clobber winstate->temp_slot_2. */ -static bool +static int row_is_in_frame(WindowAggState *winstate, int64 pos, TupleTableSlot *slot) { int frameOptions = winstate->frameOptions; Assert(pos >= 0); /* else caller error */ - /* First, check frame starting conditions */ - if (frameOptions & FRAMEOPTION_START_CURRENT_ROW) - { - if (frameOptions & FRAMEOPTION_ROWS) - { - /* rows before current row are out of frame */ - if (pos < winstate->currentpos) - return false; - } - else if (frameOptions & FRAMEOPTION_RANGE) - { - /* preceding row that is not peer is out of frame */ - if (pos < winstate->currentpos && - !are_peers(winstate, slot, winstate->ss.ss_ScanTupleSlot)) - return false; - } - else - Assert(false); - } - else if (frameOptions & FRAMEOPTION_START_VALUE) - { - if (frameOptions & FRAMEOPTION_ROWS) - { - int64 offset = DatumGetInt64(winstate->startOffsetValue); - - /* rows before current row + offset are out of frame */ - if (frameOptions & FRAMEOPTION_START_VALUE_PRECEDING) - offset = -offset; - - if (pos < winstate->currentpos + offset) - return false; - } - else if (frameOptions & FRAMEOPTION_RANGE) - { - /* parser should have rejected this */ - elog(ERROR, "window frame with value offset is not implemented"); - } - else - Assert(false); - } + /* + * First, check frame starting conditions. We might as well delegate this + * to update_frameheadpos always; it doesn't add any notable cost. + */ + update_frameheadpos(winstate); + if (pos < winstate->frameheadpos) + return 0; - /* Okay so far, now check frame ending conditions */ + /* + * Okay so far, now check frame ending conditions. Here, we avoid calling + * update_frametailpos in simple cases, so as not to spool tuples further + * ahead than necessary. + */ if (frameOptions & FRAMEOPTION_END_CURRENT_ROW) { if (frameOptions & FRAMEOPTION_ROWS) { /* rows after current row are out of frame */ if (pos > winstate->currentpos) - return false; + return -1; } - else if (frameOptions & FRAMEOPTION_RANGE) + else if (frameOptions & (FRAMEOPTION_RANGE | FRAMEOPTION_GROUPS)) { /* following row that is not peer is out of frame */ if (pos > winstate->currentpos && !are_peers(winstate, slot, winstate->ss.ss_ScanTupleSlot)) - return false; + return -1; } else Assert(false); } - else if (frameOptions & FRAMEOPTION_END_VALUE) + else if (frameOptions & FRAMEOPTION_END_OFFSET) { if (frameOptions & FRAMEOPTION_ROWS) { int64 offset = DatumGetInt64(winstate->endOffsetValue); /* rows after current row + offset are out of frame */ - if (frameOptions & FRAMEOPTION_END_VALUE_PRECEDING) + if (frameOptions & FRAMEOPTION_END_OFFSET_PRECEDING) offset = -offset; if (pos > winstate->currentpos + offset) - return false; + return -1; } - else if (frameOptions & FRAMEOPTION_RANGE) + else if (frameOptions & (FRAMEOPTION_RANGE | FRAMEOPTION_GROUPS)) { - /* parser should have rejected this */ - elog(ERROR, "window frame with value offset is not implemented"); + /* hard cases, so delegate to update_frametailpos */ + update_frametailpos(winstate); + if (pos >= winstate->frametailpos) + return -1; } else Assert(false); } + /* Check exclusion clause */ + if (frameOptions & FRAMEOPTION_EXCLUDE_CURRENT_ROW) + { + if (pos == winstate->currentpos) + return 0; + } + else if ((frameOptions & FRAMEOPTION_EXCLUDE_GROUP) || + ((frameOptions & FRAMEOPTION_EXCLUDE_TIES) && + pos != winstate->currentpos)) + { + WindowAgg *node = (WindowAgg *) winstate->ss.ps.plan; + + /* If no ORDER BY, all rows are peers with each other */ + if (node->ordNumCols == 0) + return 0; + /* Otherwise, check the group boundaries */ + if (pos >= winstate->groupheadpos) + { + update_grouptailpos(winstate); + if (pos < winstate->grouptailpos) + return 0; + } + } + /* If we get here, it's in frame */ - return true; + return 1; } /* * update_frameheadpos * make frameheadpos valid for the current row * - * Uses the winobj's read pointer for any required fetches; hence, if the - * frame mode is one that requires row comparisons, the winobj's mark must - * not be past the currently known frame head. Also uses the specified slot - * for any required fetches. + * Note that frameheadpos is computed without regard for any window exclusion + * clause; the current row and/or its peers are considered part of the frame + * for this purpose even if they must be excluded later. + * + * May clobber winstate->temp_slot_2. */ static void -update_frameheadpos(WindowObject winobj, TupleTableSlot *slot) +update_frameheadpos(WindowAggState *winstate) { - WindowAggState *winstate = winobj->winstate; WindowAgg *node = (WindowAgg *) winstate->ss.ps.plan; int frameOptions = winstate->frameOptions; + MemoryContext oldcontext; if (winstate->framehead_valid) return; /* already known for current row */ + /* We may be called in a short-lived context */ + oldcontext = MemoryContextSwitchTo(winstate->ss.ps.ps_ExprContext->ecxt_per_query_memory); + if (frameOptions & FRAMEOPTION_START_UNBOUNDED_PRECEDING) { /* In UNBOUNDED PRECEDING mode, frame head is always row 0 */ @@ -1402,58 +1479,67 @@ update_frameheadpos(WindowObject winobj, TupleTableSlot *slot) winstate->frameheadpos = winstate->currentpos; winstate->framehead_valid = true; } - else if (frameOptions & FRAMEOPTION_RANGE) + else if (frameOptions & (FRAMEOPTION_RANGE | FRAMEOPTION_GROUPS)) { - int64 fhprev; - /* If no ORDER BY, all rows are peers with each other */ if (node->ordNumCols == 0) { winstate->frameheadpos = 0; winstate->framehead_valid = true; + MemoryContextSwitchTo(oldcontext); return; } /* - * In RANGE START_CURRENT mode, frame head is the first row that - * is a peer of current row. We search backwards from current, - * which could be a bit inefficient if peer sets are large. Might - * be better to have a separate read pointer that moves forward - * tracking the frame head. + * In RANGE or GROUPS START_CURRENT_ROW mode, frame head is the + * first row that is a peer of current row. We keep a copy of the + * last-known frame head row in framehead_slot, and advance as + * necessary. Note that if we reach end of partition, we will + * leave frameheadpos = end+1 and framehead_slot empty. */ - fhprev = winstate->currentpos - 1; - for (;;) + tuplestore_select_read_pointer(winstate->buffer, + winstate->framehead_ptr); + if (winstate->frameheadpos == 0 && + TupIsNull(winstate->framehead_slot)) { - /* assume the frame head can't go backwards */ - if (fhprev < winstate->frameheadpos) - break; - if (!window_gettupleslot(winobj, fhprev, slot)) - break; /* start of partition */ - if (!are_peers(winstate, slot, winstate->ss.ss_ScanTupleSlot)) - break; /* not peer of current row */ - fhprev--; + /* fetch first row into framehead_slot, if we didn't already */ + if (!tuplestore_gettupleslot(winstate->buffer, true, true, + winstate->framehead_slot)) + elog(ERROR, "unexpected end of tuplestore"); + } + + while (!TupIsNull(winstate->framehead_slot)) + { + if (are_peers(winstate, winstate->framehead_slot, + winstate->ss.ss_ScanTupleSlot)) + break; /* this row is the correct frame head */ + /* Note we advance frameheadpos even if the fetch fails */ + winstate->frameheadpos++; + spool_tuples(winstate, winstate->frameheadpos); + if (!tuplestore_gettupleslot(winstate->buffer, true, true, + winstate->framehead_slot)) + break; /* end of partition */ } - winstate->frameheadpos = fhprev + 1; winstate->framehead_valid = true; } else Assert(false); } - else if (frameOptions & FRAMEOPTION_START_VALUE) + else if (frameOptions & FRAMEOPTION_START_OFFSET) { if (frameOptions & FRAMEOPTION_ROWS) { /* In ROWS mode, bound is physically n before/after current */ int64 offset = DatumGetInt64(winstate->startOffsetValue); - if (frameOptions & FRAMEOPTION_START_VALUE_PRECEDING) + if (frameOptions & FRAMEOPTION_START_OFFSET_PRECEDING) offset = -offset; winstate->frameheadpos = winstate->currentpos + offset; /* frame head can't go before first row */ if (winstate->frameheadpos < 0) winstate->frameheadpos = 0; - else if (winstate->frameheadpos > winstate->currentpos) + else if (winstate->frameheadpos > winstate->currentpos + 1) { /* make sure frameheadpos is not past end of partition */ spool_tuples(winstate, winstate->frameheadpos - 1); @@ -1464,40 +1550,172 @@ update_frameheadpos(WindowObject winobj, TupleTableSlot *slot) } else if (frameOptions & FRAMEOPTION_RANGE) { - /* parser should have rejected this */ - elog(ERROR, "window frame with value offset is not implemented"); + /* + * In RANGE START_OFFSET mode, frame head is the first row that + * satisfies the in_range constraint relative to the current row. + * We keep a copy of the last-known frame head row in + * framehead_slot, and advance as necessary. Note that if we + * reach end of partition, we will leave frameheadpos = end+1 and + * framehead_slot empty. + */ + bool sub, + less; + + /* Precompute flags for in_range checks */ + if (frameOptions & FRAMEOPTION_START_OFFSET_PRECEDING) + sub = true; /* subtract startOffset from current row */ + else + sub = false; /* add it */ + less = false; /* normally, we want frame head >= sum */ + /* If sort order is descending, flip both flags */ + if (!winstate->inRangeAsc) + { + sub = !sub; + less = true; + } + + tuplestore_select_read_pointer(winstate->buffer, + winstate->framehead_ptr); + if (winstate->frameheadpos == 0 && + TupIsNull(winstate->framehead_slot)) + { + /* fetch first row into framehead_slot, if we didn't already */ + if (!tuplestore_gettupleslot(winstate->buffer, true, true, + winstate->framehead_slot)) + elog(ERROR, "unexpected end of tuplestore"); + } + + while (!TupIsNull(winstate->framehead_slot)) + { + Datum headval, + currval; + bool headisnull, + currisnull; + + headval = slot_getattr(winstate->framehead_slot, 1, + &headisnull); + currval = slot_getattr(winstate->ss.ss_ScanTupleSlot, 1, + &currisnull); + if (headisnull || currisnull) + { + /* order of the rows depends only on nulls_first */ + if (winstate->inRangeNullsFirst) + { + /* advance head if head is null and curr is not */ + if (!headisnull || currisnull) + break; + } + else + { + /* advance head if head is not null and curr is null */ + if (headisnull || !currisnull) + break; + } + } + else + { + if (DatumGetBool(FunctionCall5Coll(&winstate->startInRangeFunc, + winstate->inRangeColl, + headval, + currval, + winstate->startOffsetValue, + BoolGetDatum(sub), + BoolGetDatum(less)))) + break; /* this row is the correct frame head */ + } + /* Note we advance frameheadpos even if the fetch fails */ + winstate->frameheadpos++; + spool_tuples(winstate, winstate->frameheadpos); + if (!tuplestore_gettupleslot(winstate->buffer, true, true, + winstate->framehead_slot)) + break; /* end of partition */ + } + winstate->framehead_valid = true; + } + else if (frameOptions & FRAMEOPTION_GROUPS) + { + /* + * In GROUPS START_OFFSET mode, frame head is the first row of the + * first peer group whose number satisfies the offset constraint. + * We keep a copy of the last-known frame head row in + * framehead_slot, and advance as necessary. Note that if we + * reach end of partition, we will leave frameheadpos = end+1 and + * framehead_slot empty. + */ + int64 offset = DatumGetInt64(winstate->startOffsetValue); + int64 minheadgroup; + + if (frameOptions & FRAMEOPTION_START_OFFSET_PRECEDING) + minheadgroup = winstate->currentgroup - offset; + else + minheadgroup = winstate->currentgroup + offset; + + tuplestore_select_read_pointer(winstate->buffer, + winstate->framehead_ptr); + if (winstate->frameheadpos == 0 && + TupIsNull(winstate->framehead_slot)) + { + /* fetch first row into framehead_slot, if we didn't already */ + if (!tuplestore_gettupleslot(winstate->buffer, true, true, + winstate->framehead_slot)) + elog(ERROR, "unexpected end of tuplestore"); + } + + while (!TupIsNull(winstate->framehead_slot)) + { + if (winstate->frameheadgroup >= minheadgroup) + break; /* this row is the correct frame head */ + ExecCopySlot(winstate->temp_slot_2, winstate->framehead_slot); + /* Note we advance frameheadpos even if the fetch fails */ + winstate->frameheadpos++; + spool_tuples(winstate, winstate->frameheadpos); + if (!tuplestore_gettupleslot(winstate->buffer, true, true, + winstate->framehead_slot)) + break; /* end of partition */ + if (!are_peers(winstate, winstate->temp_slot_2, + winstate->framehead_slot)) + winstate->frameheadgroup++; + } + ExecClearTuple(winstate->temp_slot_2); + winstate->framehead_valid = true; } else Assert(false); } else Assert(false); + + MemoryContextSwitchTo(oldcontext); } /* * update_frametailpos * make frametailpos valid for the current row * - * Uses the winobj's read pointer for any required fetches; hence, if the - * frame mode is one that requires row comparisons, the winobj's mark must - * not be past the currently known frame tail. Also uses the specified slot - * for any required fetches. + * Note that frametailpos is computed without regard for any window exclusion + * clause; the current row and/or its peers are considered part of the frame + * for this purpose even if they must be excluded later. + * + * May clobber winstate->temp_slot_2. */ static void -update_frametailpos(WindowObject winobj, TupleTableSlot *slot) +update_frametailpos(WindowAggState *winstate) { - WindowAggState *winstate = winobj->winstate; WindowAgg *node = (WindowAgg *) winstate->ss.ps.plan; int frameOptions = winstate->frameOptions; + MemoryContext oldcontext; if (winstate->frametail_valid) return; /* already known for current row */ + /* We may be called in a short-lived context */ + oldcontext = MemoryContextSwitchTo(winstate->ss.ps.ps_ExprContext->ecxt_per_query_memory); + if (frameOptions & FRAMEOPTION_END_UNBOUNDED_FOLLOWING) { /* In UNBOUNDED FOLLOWING mode, all partition rows are in frame */ spool_tuples(winstate, -1); - winstate->frametailpos = winstate->spooled_rows - 1; + winstate->frametailpos = winstate->spooled_rows; winstate->frametail_valid = true; } else if (frameOptions & FRAMEOPTION_END_CURRENT_ROW) @@ -1505,77 +1723,276 @@ update_frametailpos(WindowObject winobj, TupleTableSlot *slot) if (frameOptions & FRAMEOPTION_ROWS) { /* In ROWS mode, exactly the rows up to current are in frame */ - winstate->frametailpos = winstate->currentpos; + winstate->frametailpos = winstate->currentpos + 1; winstate->frametail_valid = true; } - else if (frameOptions & FRAMEOPTION_RANGE) + else if (frameOptions & (FRAMEOPTION_RANGE | FRAMEOPTION_GROUPS)) { - int64 ftnext; - /* If no ORDER BY, all rows are peers with each other */ if (node->ordNumCols == 0) { spool_tuples(winstate, -1); - winstate->frametailpos = winstate->spooled_rows - 1; + winstate->frametailpos = winstate->spooled_rows; winstate->frametail_valid = true; + MemoryContextSwitchTo(oldcontext); return; } /* - * Else we have to search for the first non-peer of the current - * row. We assume the current value of frametailpos is a lower - * bound on the possible frame tail location, ie, frame tail never - * goes backward, and that currentpos is also a lower bound, ie, - * frame end always >= current row. + * In RANGE or GROUPS END_CURRENT_ROW mode, frame end is the last + * row that is a peer of current row, frame tail is the row after + * that (if any). We keep a copy of the last-known frame tail row + * in frametail_slot, and advance as necessary. Note that if we + * reach end of partition, we will leave frametailpos = end+1 and + * frametail_slot empty. */ - ftnext = Max(winstate->frametailpos, winstate->currentpos) + 1; - for (;;) + tuplestore_select_read_pointer(winstate->buffer, + winstate->frametail_ptr); + if (winstate->frametailpos == 0 && + TupIsNull(winstate->frametail_slot)) + { + /* fetch first row into frametail_slot, if we didn't already */ + if (!tuplestore_gettupleslot(winstate->buffer, true, true, + winstate->frametail_slot)) + elog(ERROR, "unexpected end of tuplestore"); + } + + while (!TupIsNull(winstate->frametail_slot)) { - if (!window_gettupleslot(winobj, ftnext, slot)) + if (winstate->frametailpos > winstate->currentpos && + !are_peers(winstate, winstate->frametail_slot, + winstate->ss.ss_ScanTupleSlot)) + break; /* this row is the frame tail */ + /* Note we advance frametailpos even if the fetch fails */ + winstate->frametailpos++; + spool_tuples(winstate, winstate->frametailpos); + if (!tuplestore_gettupleslot(winstate->buffer, true, true, + winstate->frametail_slot)) break; /* end of partition */ - if (!are_peers(winstate, slot, winstate->ss.ss_ScanTupleSlot)) - break; /* not peer of current row */ - ftnext++; } - winstate->frametailpos = ftnext - 1; winstate->frametail_valid = true; } else Assert(false); } - else if (frameOptions & FRAMEOPTION_END_VALUE) + else if (frameOptions & FRAMEOPTION_END_OFFSET) { if (frameOptions & FRAMEOPTION_ROWS) { /* In ROWS mode, bound is physically n before/after current */ int64 offset = DatumGetInt64(winstate->endOffsetValue); - if (frameOptions & FRAMEOPTION_END_VALUE_PRECEDING) + if (frameOptions & FRAMEOPTION_END_OFFSET_PRECEDING) offset = -offset; - winstate->frametailpos = winstate->currentpos + offset; - /* smallest allowable value of frametailpos is -1 */ + winstate->frametailpos = winstate->currentpos + offset + 1; + /* smallest allowable value of frametailpos is 0 */ if (winstate->frametailpos < 0) - winstate->frametailpos = -1; - else if (winstate->frametailpos > winstate->currentpos) + winstate->frametailpos = 0; + else if (winstate->frametailpos > winstate->currentpos + 1) { - /* make sure frametailpos is not past last row of partition */ - spool_tuples(winstate, winstate->frametailpos); - if (winstate->frametailpos >= winstate->spooled_rows) - winstate->frametailpos = winstate->spooled_rows - 1; + /* make sure frametailpos is not past end of partition */ + spool_tuples(winstate, winstate->frametailpos - 1); + if (winstate->frametailpos > winstate->spooled_rows) + winstate->frametailpos = winstate->spooled_rows; } winstate->frametail_valid = true; } else if (frameOptions & FRAMEOPTION_RANGE) { - /* parser should have rejected this */ - elog(ERROR, "window frame with value offset is not implemented"); + /* + * In RANGE END_OFFSET mode, frame end is the last row that + * satisfies the in_range constraint relative to the current row, + * frame tail is the row after that (if any). We keep a copy of + * the last-known frame tail row in frametail_slot, and advance as + * necessary. Note that if we reach end of partition, we will + * leave frametailpos = end+1 and frametail_slot empty. + */ + bool sub, + less; + + /* Precompute flags for in_range checks */ + if (frameOptions & FRAMEOPTION_END_OFFSET_PRECEDING) + sub = true; /* subtract endOffset from current row */ + else + sub = false; /* add it */ + less = true; /* normally, we want frame tail <= sum */ + /* If sort order is descending, flip both flags */ + if (!winstate->inRangeAsc) + { + sub = !sub; + less = false; + } + + tuplestore_select_read_pointer(winstate->buffer, + winstate->frametail_ptr); + if (winstate->frametailpos == 0 && + TupIsNull(winstate->frametail_slot)) + { + /* fetch first row into frametail_slot, if we didn't already */ + if (!tuplestore_gettupleslot(winstate->buffer, true, true, + winstate->frametail_slot)) + elog(ERROR, "unexpected end of tuplestore"); + } + + while (!TupIsNull(winstate->frametail_slot)) + { + Datum tailval, + currval; + bool tailisnull, + currisnull; + + tailval = slot_getattr(winstate->frametail_slot, 1, + &tailisnull); + currval = slot_getattr(winstate->ss.ss_ScanTupleSlot, 1, + &currisnull); + if (tailisnull || currisnull) + { + /* order of the rows depends only on nulls_first */ + if (winstate->inRangeNullsFirst) + { + /* advance tail if tail is null or curr is not */ + if (!tailisnull) + break; + } + else + { + /* advance tail if tail is not null or curr is null */ + if (!currisnull) + break; + } + } + else + { + if (!DatumGetBool(FunctionCall5Coll(&winstate->endInRangeFunc, + winstate->inRangeColl, + tailval, + currval, + winstate->endOffsetValue, + BoolGetDatum(sub), + BoolGetDatum(less)))) + break; /* this row is the correct frame tail */ + } + /* Note we advance frametailpos even if the fetch fails */ + winstate->frametailpos++; + spool_tuples(winstate, winstate->frametailpos); + if (!tuplestore_gettupleslot(winstate->buffer, true, true, + winstate->frametail_slot)) + break; /* end of partition */ + } + winstate->frametail_valid = true; + } + else if (frameOptions & FRAMEOPTION_GROUPS) + { + /* + * In GROUPS END_OFFSET mode, frame end is the last row of the + * last peer group whose number satisfies the offset constraint, + * and frame tail is the row after that (if any). We keep a copy + * of the last-known frame tail row in frametail_slot, and advance + * as necessary. Note that if we reach end of partition, we will + * leave frametailpos = end+1 and frametail_slot empty. + */ + int64 offset = DatumGetInt64(winstate->endOffsetValue); + int64 maxtailgroup; + + if (frameOptions & FRAMEOPTION_END_OFFSET_PRECEDING) + maxtailgroup = winstate->currentgroup - offset; + else + maxtailgroup = winstate->currentgroup + offset; + + tuplestore_select_read_pointer(winstate->buffer, + winstate->frametail_ptr); + if (winstate->frametailpos == 0 && + TupIsNull(winstate->frametail_slot)) + { + /* fetch first row into frametail_slot, if we didn't already */ + if (!tuplestore_gettupleslot(winstate->buffer, true, true, + winstate->frametail_slot)) + elog(ERROR, "unexpected end of tuplestore"); + } + + while (!TupIsNull(winstate->frametail_slot)) + { + if (winstate->frametailgroup > maxtailgroup) + break; /* this row is the correct frame tail */ + ExecCopySlot(winstate->temp_slot_2, winstate->frametail_slot); + /* Note we advance frametailpos even if the fetch fails */ + winstate->frametailpos++; + spool_tuples(winstate, winstate->frametailpos); + if (!tuplestore_gettupleslot(winstate->buffer, true, true, + winstate->frametail_slot)) + break; /* end of partition */ + if (!are_peers(winstate, winstate->temp_slot_2, + winstate->frametail_slot)) + winstate->frametailgroup++; + } + ExecClearTuple(winstate->temp_slot_2); + winstate->frametail_valid = true; } else Assert(false); } else Assert(false); + + MemoryContextSwitchTo(oldcontext); +} + +/* + * update_grouptailpos + * make grouptailpos valid for the current row + * + * May clobber winstate->temp_slot_2. + */ +static void +update_grouptailpos(WindowAggState *winstate) +{ + WindowAgg *node = (WindowAgg *) winstate->ss.ps.plan; + MemoryContext oldcontext; + + if (winstate->grouptail_valid) + return; /* already known for current row */ + + /* We may be called in a short-lived context */ + oldcontext = MemoryContextSwitchTo(winstate->ss.ps.ps_ExprContext->ecxt_per_query_memory); + + /* If no ORDER BY, all rows are peers with each other */ + if (node->ordNumCols == 0) + { + spool_tuples(winstate, -1); + winstate->grouptailpos = winstate->spooled_rows; + winstate->grouptail_valid = true; + MemoryContextSwitchTo(oldcontext); + return; + } + + /* + * Because grouptail_valid is reset only when current row advances into a + * new peer group, we always reach here knowing that grouptailpos needs to + * be advanced by at least one row. Hence, unlike the otherwise similar + * case for frame tail tracking, we do not need persistent storage of the + * group tail row. + */ + Assert(winstate->grouptailpos <= winstate->currentpos); + tuplestore_select_read_pointer(winstate->buffer, + winstate->grouptail_ptr); + for (;;) + { + /* Note we advance grouptailpos even if the fetch fails */ + winstate->grouptailpos++; + spool_tuples(winstate, winstate->grouptailpos); + if (!tuplestore_gettupleslot(winstate->buffer, true, true, + winstate->temp_slot_2)) + break; /* end of partition */ + if (winstate->grouptailpos > winstate->currentpos && + !are_peers(winstate, winstate->temp_slot_2, + winstate->ss.ss_ScanTupleSlot)) + break; /* this row is the group tail */ + } + ExecClearTuple(winstate->temp_slot_2); + winstate->grouptail_valid = true; + + MemoryContextSwitchTo(oldcontext); } @@ -1602,7 +2019,9 @@ ExecWindowAgg(PlanState *pstate) return NULL; /* - * Compute frame offset values, if any, during first call. + * Compute frame offset values, if any, during first call (or after a + * rescan). These are assumed to hold constant throughout the scan; if + * user gives us a volatile expression, we'll only use its initial value. */ if (winstate->all_first) { @@ -1613,7 +2032,7 @@ ExecWindowAgg(PlanState *pstate) int16 len; bool byval; - if (frameOptions & FRAMEOPTION_START_VALUE) + if (frameOptions & FRAMEOPTION_START_OFFSET) { Assert(winstate->startOffset != NULL); value = ExecEvalExprSwitchContext(winstate->startOffset, @@ -1627,18 +2046,18 @@ ExecWindowAgg(PlanState *pstate) get_typlenbyval(exprType((Node *) winstate->startOffset->expr), &len, &byval); winstate->startOffsetValue = datumCopy(value, byval, len); - if (frameOptions & FRAMEOPTION_ROWS) + if (frameOptions & (FRAMEOPTION_ROWS | FRAMEOPTION_GROUPS)) { /* value is known to be int8 */ int64 offset = DatumGetInt64(value); if (offset < 0) ereport(ERROR, - (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + (errcode(ERRCODE_INVALID_PRECEDING_FOLLOWING_SIZE), errmsg("frame starting offset must not be negative"))); } } - if (frameOptions & FRAMEOPTION_END_VALUE) + if (frameOptions & FRAMEOPTION_END_OFFSET) { Assert(winstate->endOffset != NULL); value = ExecEvalExprSwitchContext(winstate->endOffset, @@ -1652,14 +2071,14 @@ ExecWindowAgg(PlanState *pstate) get_typlenbyval(exprType((Node *) winstate->endOffset->expr), &len, &byval); winstate->endOffsetValue = datumCopy(value, byval, len); - if (frameOptions & FRAMEOPTION_ROWS) + if (frameOptions & (FRAMEOPTION_ROWS | FRAMEOPTION_GROUPS)) { /* value is known to be int8 */ int64 offset = DatumGetInt64(value); if (offset < 0) ereport(ERROR, - (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + (errcode(ERRCODE_INVALID_PRECEDING_FOLLOWING_SIZE), errmsg("frame ending offset must not be negative"))); } } @@ -1679,6 +2098,7 @@ ExecWindowAgg(PlanState *pstate) /* This might mean that the frame moves, too */ winstate->framehead_valid = false; winstate->frametail_valid = false; + /* we don't need to invalidate grouptail here; see below */ } /* @@ -1718,12 +2138,38 @@ ExecWindowAgg(PlanState *pstate) * out of the tuplestore, since window function evaluation might cause the * tuplestore to dump its state to disk.) * + * In GROUPS mode, or when tracking a group-oriented exclusion clause, we + * must also detect entering a new peer group and update associated state + * when that happens. We use temp_slot_2 to temporarily hold the previous + * row for this purpose. + * * Current row must be in the tuplestore, since we spooled it above. */ tuplestore_select_read_pointer(winstate->buffer, winstate->current_ptr); - if (!tuplestore_gettupleslot(winstate->buffer, true, true, - winstate->ss.ss_ScanTupleSlot)) - elog(ERROR, "unexpected end of tuplestore"); + if ((winstate->frameOptions & (FRAMEOPTION_GROUPS | + FRAMEOPTION_EXCLUDE_GROUP | + FRAMEOPTION_EXCLUDE_TIES)) && + winstate->currentpos > 0) + { + ExecCopySlot(winstate->temp_slot_2, winstate->ss.ss_ScanTupleSlot); + if (!tuplestore_gettupleslot(winstate->buffer, true, true, + winstate->ss.ss_ScanTupleSlot)) + elog(ERROR, "unexpected end of tuplestore"); + if (!are_peers(winstate, winstate->temp_slot_2, + winstate->ss.ss_ScanTupleSlot)) + { + winstate->currentgroup++; + winstate->groupheadpos = winstate->currentpos; + winstate->grouptail_valid = false; + } + ExecClearTuple(winstate->temp_slot_2); + } + else + { + if (!tuplestore_gettupleslot(winstate->buffer, true, true, + winstate->ss.ss_ScanTupleSlot)) + elog(ERROR, "unexpected end of tuplestore"); + } /* * Evaluate true window functions @@ -1747,6 +2193,23 @@ ExecWindowAgg(PlanState *pstate) eval_windowaggregates(winstate); /* + * If we have created auxiliary read pointers for the frame or group + * boundaries, force them to be kept up-to-date, because we don't know + * whether the window function(s) will do anything that requires that. + * Failing to advance the pointers would result in being unable to trim + * data from the tuplestore, which is bad. (If we could know in advance + * whether the window functions will use frame boundary info, we could + * skip creating these pointers in the first place ... but unfortunately + * the window function API doesn't require that.) + */ + if (winstate->framehead_ptr >= 0) + update_frameheadpos(winstate); + if (winstate->frametail_ptr >= 0) + update_frametailpos(winstate); + if (winstate->grouptail_ptr >= 0) + update_grouptailpos(winstate); + + /* * Truncate any no-longer-needed rows from the tuplestore. */ tuplestore_trim(winstate->buffer); @@ -1777,6 +2240,7 @@ ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags) ExprContext *tmpcontext; WindowStatePerFunc perfunc; WindowStatePerAgg peragg; + int frameOptions = node->frameOptions; int numfuncs, wfuncno, numaggs, @@ -1832,6 +2296,20 @@ ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags) winstate->temp_slot_2 = ExecInitExtraTupleSlot(estate); /* + * create frame head and tail slots only if needed (must match logic in + * update_frameheadpos and update_frametailpos) + */ + winstate->framehead_slot = winstate->frametail_slot = NULL; + + if (frameOptions & (FRAMEOPTION_RANGE | FRAMEOPTION_GROUPS)) + { + if (!(frameOptions & FRAMEOPTION_START_UNBOUNDED_PRECEDING)) + winstate->framehead_slot = ExecInitExtraTupleSlot(estate); + if (!(frameOptions & FRAMEOPTION_END_UNBOUNDED_FOLLOWING)) + winstate->frametail_slot = ExecInitExtraTupleSlot(estate); + } + + /* * WindowAgg nodes never have quals, since they can only occur at the * logical top level of a query (ie, after any WHERE or HAVING filters) */ @@ -1858,6 +2336,12 @@ ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags) winstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor); ExecSetSlotDescriptor(winstate->temp_slot_2, winstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor); + if (winstate->framehead_slot) + ExecSetSlotDescriptor(winstate->framehead_slot, + winstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor); + if (winstate->frametail_slot) + ExecSetSlotDescriptor(winstate->frametail_slot, + winstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor); /* * Initialize result tuple type and projection info. @@ -1991,7 +2475,7 @@ ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags) } /* copy frame options to state node for easy access */ - winstate->frameOptions = node->frameOptions; + winstate->frameOptions = frameOptions; /* initialize frame bound offset expressions */ winstate->startOffset = ExecInitExpr((Expr *) node->startOffset, @@ -1999,6 +2483,15 @@ ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags) winstate->endOffset = ExecInitExpr((Expr *) node->endOffset, (PlanState *) winstate); + /* Lookup in_range support functions if needed */ + if (OidIsValid(node->startInRangeFunc)) + fmgr_info(node->startInRangeFunc, &winstate->startInRangeFunc); + if (OidIsValid(node->endInRangeFunc)) + fmgr_info(node->endInRangeFunc, &winstate->endInRangeFunc); + winstate->inRangeColl = node->inRangeColl; + winstate->inRangeAsc = node->inRangeAsc; + winstate->inRangeNullsFirst = node->inRangeNullsFirst; + winstate->all_first = true; winstate->partition_spooled = false; winstate->more_partitions = false; @@ -2023,6 +2516,10 @@ ExecEndWindowAgg(WindowAggState *node) ExecClearTuple(node->agg_row_slot); ExecClearTuple(node->temp_slot_1); ExecClearTuple(node->temp_slot_2); + if (node->framehead_slot) + ExecClearTuple(node->framehead_slot); + if (node->frametail_slot) + ExecClearTuple(node->frametail_slot); /* * Free both the expr contexts. @@ -2068,6 +2565,10 @@ ExecReScanWindowAgg(WindowAggState *node) ExecClearTuple(node->agg_row_slot); ExecClearTuple(node->temp_slot_1); ExecClearTuple(node->temp_slot_2); + if (node->framehead_slot) + ExecClearTuple(node->framehead_slot); + if (node->frametail_slot) + ExecClearTuple(node->frametail_slot); /* Forget current wfunc values */ MemSet(econtext->ecxt_aggvalues, 0, sizeof(Datum) * node->numfuncs); @@ -2574,7 +3075,7 @@ WinSetMarkPosition(WindowObject winobj, int64 markpos) /* * WinRowsArePeers - * Compare two rows (specified by absolute position in window) to see + * Compare two rows (specified by absolute position in partition) to see * if they are equal according to the ORDER BY clause. * * NB: this does not consider the window frame mode. @@ -2596,6 +3097,10 @@ WinRowsArePeers(WindowObject winobj, int64 pos1, int64 pos2) if (node->ordNumCols == 0) return true; + /* + * Note: OK to use temp_slot_2 here because we aren't calling any + * frame-related functions (those tend to clobber temp_slot_2). + */ slot1 = winstate->temp_slot_1; slot2 = winstate->temp_slot_2; @@ -2680,30 +3185,7 @@ WinGetFuncArgInPartition(WindowObject winobj, int argno, if (isout) *isout = false; if (set_mark) - { - int frameOptions = winstate->frameOptions; - int64 mark_pos = abs_pos; - - /* - * In RANGE mode with a moving frame head, we must not let the - * mark advance past frameheadpos, since that row has to be - * fetchable during future update_frameheadpos calls. - * - * XXX it is very ugly to pollute window functions' marks with - * this consideration; it could for instance mask a logic bug that - * lets a window function fetch rows before what it had claimed - * was its mark. Perhaps use a separate mark for frame head - * probes? - */ - if ((frameOptions & FRAMEOPTION_RANGE) && - !(frameOptions & FRAMEOPTION_START_UNBOUNDED_PRECEDING)) - { - update_frameheadpos(winobj, winstate->temp_slot_2); - if (mark_pos > winstate->frameheadpos) - mark_pos = winstate->frameheadpos; - } - WinSetMarkPosition(winobj, mark_pos); - } + WinSetMarkPosition(winobj, abs_pos); econtext->ecxt_outertuple = slot; return ExecEvalExpr((ExprState *) list_nth(winobj->argstates, argno), econtext, isnull); @@ -2714,19 +3196,34 @@ WinGetFuncArgInPartition(WindowObject winobj, int argno, * WinGetFuncArgInFrame * Evaluate a window function's argument expression on a specified * row of the window frame. The row is identified in lseek(2) style, - * i.e. relative to the current, first, or last row. + * i.e. relative to the first or last row of the frame. (We do not + * support WINDOW_SEEK_CURRENT here, because it's not very clear what + * that should mean if the current row isn't part of the frame.) * * argno: argument number to evaluate (counted from 0) * relpos: signed rowcount offset from the seek position - * seektype: WINDOW_SEEK_CURRENT, WINDOW_SEEK_HEAD, or WINDOW_SEEK_TAIL - * set_mark: If the row is found and set_mark is true, the mark is moved to - * the row as a side-effect. + * seektype: WINDOW_SEEK_HEAD or WINDOW_SEEK_TAIL + * set_mark: If the row is found/in frame and set_mark is true, the mark is + * moved to the row as a side-effect. * isnull: output argument, receives isnull status of result * isout: output argument, set to indicate whether target row position * is out of frame (can pass NULL if caller doesn't care about this) * - * Specifying a nonexistent row is not an error, it just causes a null result - * (plus setting *isout true, if isout isn't NULL). + * Specifying a nonexistent or not-in-frame row is not an error, it just + * causes a null result (plus setting *isout true, if isout isn't NULL). + * + * Note that some exclusion-clause options lead to situations where the + * rows that are in-frame are not consecutive in the partition. But we + * count only in-frame rows when measuring relpos. + * + * The set_mark flag is interpreted as meaning that the caller will specify + * a constant (or, perhaps, monotonically increasing) relpos in successive + * calls, so that *if there is no exclusion clause* there will be no need + * to fetch a row before the previously fetched row. But we do not expect + * the caller to know how to account for exclusion clauses. Therefore, + * if there is an exclusion clause we take responsibility for adjusting the + * mark request to something that will be safe given the above assumption + * about relpos. */ Datum WinGetFuncArgInFrame(WindowObject winobj, int argno, @@ -2736,8 +3233,8 @@ WinGetFuncArgInFrame(WindowObject winobj, int argno, WindowAggState *winstate; ExprContext *econtext; TupleTableSlot *slot; - bool gottuple; int64 abs_pos; + int64 mark_pos; Assert(WindowObjectIsValid(winobj)); winstate = winobj->winstate; @@ -2747,66 +3244,167 @@ WinGetFuncArgInFrame(WindowObject winobj, int argno, switch (seektype) { case WINDOW_SEEK_CURRENT: - abs_pos = winstate->currentpos + relpos; + elog(ERROR, "WINDOW_SEEK_CURRENT is not supported for WinGetFuncArgInFrame"); + abs_pos = mark_pos = 0; /* keep compiler quiet */ break; case WINDOW_SEEK_HEAD: - update_frameheadpos(winobj, slot); + /* rejecting relpos < 0 is easy and simplifies code below */ + if (relpos < 0) + goto out_of_frame; + update_frameheadpos(winstate); abs_pos = winstate->frameheadpos + relpos; + mark_pos = abs_pos; + + /* + * Account for exclusion option if one is active, but advance only + * abs_pos not mark_pos. This prevents changes of the current + * row's peer group from resulting in trying to fetch a row before + * some previous mark position. + * + * Note that in some corner cases such as current row being + * outside frame, these calculations are theoretically too simple, + * but it doesn't matter because we'll end up deciding the row is + * out of frame. We do not attempt to avoid fetching rows past + * end of frame; that would happen in some cases anyway. + */ + switch (winstate->frameOptions & FRAMEOPTION_EXCLUSION) + { + case 0: + /* no adjustment needed */ + break; + case FRAMEOPTION_EXCLUDE_CURRENT_ROW: + if (abs_pos >= winstate->currentpos && + winstate->currentpos >= winstate->frameheadpos) + abs_pos++; + break; + case FRAMEOPTION_EXCLUDE_GROUP: + update_grouptailpos(winstate); + if (abs_pos >= winstate->groupheadpos && + winstate->grouptailpos > winstate->frameheadpos) + { + int64 overlapstart = Max(winstate->groupheadpos, + winstate->frameheadpos); + + abs_pos += winstate->grouptailpos - overlapstart; + } + break; + case FRAMEOPTION_EXCLUDE_TIES: + update_grouptailpos(winstate); + if (abs_pos >= winstate->groupheadpos && + winstate->grouptailpos > winstate->frameheadpos) + { + int64 overlapstart = Max(winstate->groupheadpos, + winstate->frameheadpos); + + if (abs_pos == overlapstart) + abs_pos = winstate->currentpos; + else + abs_pos += winstate->grouptailpos - overlapstart - 1; + } + break; + default: + elog(ERROR, "unrecognized frame option state: 0x%x", + winstate->frameOptions); + break; + } break; case WINDOW_SEEK_TAIL: - update_frametailpos(winobj, slot); - abs_pos = winstate->frametailpos + relpos; + /* rejecting relpos > 0 is easy and simplifies code below */ + if (relpos > 0) + goto out_of_frame; + update_frametailpos(winstate); + abs_pos = winstate->frametailpos - 1 + relpos; + + /* + * Account for exclusion option if one is active. If there is no + * exclusion, we can safely set the mark at the accessed row. But + * if there is, we can only mark the frame start, because we can't + * be sure how far back in the frame the exclusion might cause us + * to fetch in future. Furthermore, we have to actually check + * against frameheadpos here, since it's unsafe to try to fetch a + * row before frame start if the mark might be there already. + */ + switch (winstate->frameOptions & FRAMEOPTION_EXCLUSION) + { + case 0: + /* no adjustment needed */ + mark_pos = abs_pos; + break; + case FRAMEOPTION_EXCLUDE_CURRENT_ROW: + if (abs_pos <= winstate->currentpos && + winstate->currentpos < winstate->frametailpos) + abs_pos--; + update_frameheadpos(winstate); + if (abs_pos < winstate->frameheadpos) + goto out_of_frame; + mark_pos = winstate->frameheadpos; + break; + case FRAMEOPTION_EXCLUDE_GROUP: + update_grouptailpos(winstate); + if (abs_pos < winstate->grouptailpos && + winstate->groupheadpos < winstate->frametailpos) + { + int64 overlapend = Min(winstate->grouptailpos, + winstate->frametailpos); + + abs_pos -= overlapend - winstate->groupheadpos; + } + update_frameheadpos(winstate); + if (abs_pos < winstate->frameheadpos) + goto out_of_frame; + mark_pos = winstate->frameheadpos; + break; + case FRAMEOPTION_EXCLUDE_TIES: + update_grouptailpos(winstate); + if (abs_pos < winstate->grouptailpos && + winstate->groupheadpos < winstate->frametailpos) + { + int64 overlapend = Min(winstate->grouptailpos, + winstate->frametailpos); + + if (abs_pos == overlapend - 1) + abs_pos = winstate->currentpos; + else + abs_pos -= overlapend - 1 - winstate->groupheadpos; + } + update_frameheadpos(winstate); + if (abs_pos < winstate->frameheadpos) + goto out_of_frame; + mark_pos = winstate->frameheadpos; + break; + default: + elog(ERROR, "unrecognized frame option state: 0x%x", + winstate->frameOptions); + mark_pos = 0; /* keep compiler quiet */ + break; + } break; default: elog(ERROR, "unrecognized window seek type: %d", seektype); - abs_pos = 0; /* keep compiler quiet */ + abs_pos = mark_pos = 0; /* keep compiler quiet */ break; } - gottuple = window_gettupleslot(winobj, abs_pos, slot); - if (gottuple) - gottuple = row_is_in_frame(winstate, abs_pos, slot); + if (!window_gettupleslot(winobj, abs_pos, slot)) + goto out_of_frame; - if (!gottuple) - { - if (isout) - *isout = true; - *isnull = true; - return (Datum) 0; - } - else - { - if (isout) - *isout = false; - if (set_mark) - { - int frameOptions = winstate->frameOptions; - int64 mark_pos = abs_pos; + /* The code above does not detect all out-of-frame cases, so check */ + if (row_is_in_frame(winstate, abs_pos, slot) <= 0) + goto out_of_frame; - /* - * In RANGE mode with a moving frame head, we must not let the - * mark advance past frameheadpos, since that row has to be - * fetchable during future update_frameheadpos calls. - * - * XXX it is very ugly to pollute window functions' marks with - * this consideration; it could for instance mask a logic bug that - * lets a window function fetch rows before what it had claimed - * was its mark. Perhaps use a separate mark for frame head - * probes? - */ - if ((frameOptions & FRAMEOPTION_RANGE) && - !(frameOptions & FRAMEOPTION_START_UNBOUNDED_PRECEDING)) - { - update_frameheadpos(winobj, winstate->temp_slot_2); - if (mark_pos > winstate->frameheadpos) - mark_pos = winstate->frameheadpos; - } - WinSetMarkPosition(winobj, mark_pos); - } - econtext->ecxt_outertuple = slot; - return ExecEvalExpr((ExprState *) list_nth(winobj->argstates, argno), - econtext, isnull); - } + if (isout) + *isout = false; + if (set_mark) + WinSetMarkPosition(winobj, mark_pos); + econtext->ecxt_outertuple = slot; + return ExecEvalExpr((ExprState *) list_nth(winobj->argstates, argno), + econtext, isnull); + +out_of_frame: + if (isout) + *isout = true; + *isnull = true; + return (Datum) 0; } /* |