diff options
Diffstat (limited to 'src/backend/optimizer/util')
| -rw-r--r-- | src/backend/optimizer/util/clauses.c | 10 | ||||
| -rw-r--r-- | src/backend/optimizer/util/tlist.c | 60 |
2 files changed, 67 insertions, 3 deletions
diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c index 6ac25dc6638..b692e18e3d4 100644 --- a/src/backend/optimizer/util/clauses.c +++ b/src/backend/optimizer/util/clauses.c @@ -672,9 +672,13 @@ find_window_functions_walker(Node *node, WindowFuncLists *lists) if (wfunc->winref > lists->maxWinRef) elog(ERROR, "WindowFunc contains out-of-range winref %u", wfunc->winref); - lists->windowFuncs[wfunc->winref] = - lappend(lists->windowFuncs[wfunc->winref], wfunc); - lists->numWindowFuncs++; + /* eliminate duplicates, so that we avoid repeated computation */ + if (!list_member(lists->windowFuncs[wfunc->winref], wfunc)) + { + lists->windowFuncs[wfunc->winref] = + lappend(lists->windowFuncs[wfunc->winref], wfunc); + lists->numWindowFuncs++; + } /* * We assume that the parser checked that there are no window diff --git a/src/backend/optimizer/util/tlist.c b/src/backend/optimizer/util/tlist.c index c51642fde5b..ccea3bf9d27 100644 --- a/src/backend/optimizer/util/tlist.c +++ b/src/backend/optimizer/util/tlist.c @@ -624,6 +624,66 @@ make_tlist_from_pathtarget(PathTarget *target) } /* + * copy_pathtarget + * Copy a PathTarget. + * + * The new PathTarget has its own List cells, but shares the underlying + * target expression trees with the old one. We duplicate the List cells + * so that items can be added to one target without damaging the other. + */ +PathTarget * +copy_pathtarget(PathTarget *src) +{ + PathTarget *dst = (PathTarget *) palloc(sizeof(PathTarget)); + + /* Copy scalar fields */ + memcpy(dst, src, sizeof(PathTarget)); + /* Shallow-copy the expression list */ + dst->exprs = list_copy(src->exprs); + /* Duplicate sortgrouprefs if any (if not, the memcpy handled this) */ + if (src->sortgrouprefs) + { + Size nbytes = list_length(src->exprs) * sizeof(Index); + + dst->sortgrouprefs = (Index *) palloc(nbytes); + memcpy(dst->sortgrouprefs, src->sortgrouprefs, nbytes); + } + return dst; +} + +/* + * add_column_to_pathtarget + * Append a target column to the PathTarget. + * + * As with make_pathtarget_from_tlist, we leave it to the caller to update + * the cost and width fields. + */ +void +add_column_to_pathtarget(PathTarget *target, Expr *expr, Index sortgroupref) +{ + /* Updating the exprs list is easy ... */ + target->exprs = lappend(target->exprs, expr); + /* ... the sortgroupref data, a bit less so */ + if (target->sortgrouprefs) + { + int nexprs = list_length(target->exprs); + + /* This might look inefficient, but actually it's usually cheap */ + target->sortgrouprefs = (Index *) + repalloc(target->sortgrouprefs, nexprs * sizeof(Index)); + target->sortgrouprefs[nexprs - 1] = sortgroupref; + } + else if (sortgroupref) + { + /* Adding sortgroupref labeling to a previously unlabeled target */ + int nexprs = list_length(target->exprs); + + target->sortgrouprefs = (Index *) palloc0(nexprs * sizeof(Index)); + target->sortgrouprefs[nexprs - 1] = sortgroupref; + } +} + +/* * apply_pathtarget_labeling_to_tlist * Apply any sortgrouprefs in the PathTarget to matching tlist entries * |