diff options
Diffstat (limited to 'src/backend/optimizer/path/indxpath.c')
| -rw-r--r-- | src/backend/optimizer/path/indxpath.c | 32 |
1 files changed, 31 insertions, 1 deletions
diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c index f295558f767..5f464153942 100644 --- a/src/backend/optimizer/path/indxpath.c +++ b/src/backend/optimizer/path/indxpath.c @@ -67,6 +67,7 @@ typedef struct List *quals; /* the WHERE clauses it uses */ List *preds; /* predicates of its partial index(es) */ Bitmapset *clauseids; /* quals+preds represented as a bitmapset */ + bool unclassifiable; /* has too many quals+preds to process? */ } PathClauseUsage; /* Callback argument for ec_member_matches_indexcol */ @@ -1447,9 +1448,18 @@ choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel, List *paths) Path *ipath = (Path *) lfirst(l); pathinfo = classify_index_clause_usage(ipath, &clauselist); + + /* If it's unclassifiable, treat it as distinct from all others */ + if (pathinfo->unclassifiable) + { + pathinfoarray[npaths++] = pathinfo; + continue; + } + for (i = 0; i < npaths; i++) { - if (bms_equal(pathinfo->clauseids, pathinfoarray[i]->clauseids)) + if (!pathinfoarray[i]->unclassifiable && + bms_equal(pathinfo->clauseids, pathinfoarray[i]->clauseids)) break; } if (i < npaths) @@ -1484,6 +1494,10 @@ choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel, List *paths) * For each surviving index, consider it as an "AND group leader", and see * whether adding on any of the later indexes results in an AND path with * cheaper total cost than before. Then take the cheapest AND group. + * + * Note: paths that are either clauseless or unclassifiable will have + * empty clauseids, so that they will not be rejected by the clauseids + * filter here, nor will they cause later paths to be rejected by it. */ for (i = 0; i < npaths; i++) { @@ -1711,6 +1725,21 @@ classify_index_clause_usage(Path *path, List **clauselist) result->preds = NIL; find_indexpath_quals(path, &result->quals, &result->preds); + /* + * Some machine-generated queries have outlandish numbers of qual clauses. + * To avoid getting into O(N^2) behavior even in this preliminary + * classification step, we want to limit the number of entries we can + * accumulate in *clauselist. Treat any path with more than 100 quals + + * preds as unclassifiable, which will cause calling code to consider it + * distinct from all other paths. + */ + if (list_length(result->quals) + list_length(result->preds) > 100) + { + result->clauseids = NULL; + result->unclassifiable = true; + return result; + } + /* Build up a bitmapset representing the quals and preds */ clauseids = NULL; foreach(lc, result->quals) @@ -1728,6 +1757,7 @@ classify_index_clause_usage(Path *path, List **clauselist) find_list_position(node, clauselist)); } result->clauseids = clauseids; + result->unclassifiable = false; return result; } |