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Diffstat (limited to '')
| -rw-r--r-- | src/backend/utils/adt/windowfuncs.c | 29 |
1 files changed, 23 insertions, 6 deletions
diff --git a/src/backend/utils/adt/windowfuncs.c b/src/backend/utils/adt/windowfuncs.c index b87a624..0c7cc55 100644 --- a/src/backend/utils/adt/windowfuncs.c +++ b/src/backend/utils/adt/windowfuncs.c @@ -14,6 +14,7 @@ #include "postgres.h" #include "nodes/supportnodes.h" +#include "optimizer/optimizer.h" #include "utils/builtins.h" #include "windowapi.h" @@ -486,13 +487,29 @@ window_ntile_support(PG_FUNCTION_ARGS) if (IsA(rawreq, SupportRequestWFuncMonotonic)) { SupportRequestWFuncMonotonic *req = (SupportRequestWFuncMonotonic *) rawreq; + WindowFunc *wfunc = req->window_func; - /* - * ntile() is monotonically increasing as the number of buckets cannot - * change after the first call - */ - req->monotonic = MONOTONICFUNC_INCREASING; - PG_RETURN_POINTER(req); + if (list_length(wfunc->args) == 1) + { + Node *expr = eval_const_expressions(NULL, linitial(wfunc->args)); + + /* + * Due to the Node representation of WindowClause runConditions in + * version prior to v17, we need to insist that ntile arg is Const + * to allow safe application of the runCondition optimization. + */ + if (IsA(expr, Const)) + { + /* + * ntile() is monotonically increasing as the number of + * buckets cannot change after the first call + */ + req->monotonic = MONOTONICFUNC_INCREASING; + PG_RETURN_POINTER(req); + } + } + + PG_RETURN_POINTER(NULL); } if (IsA(rawreq, SupportRequestOptimizeWindowClause)) |