From: Tim Beale Date: Sun, 3 Feb 2019 21:49:03 +0000 (+1300) Subject: ldb: Avoid inefficient one-level searches X-Git-Tag: ldb-1.3.7~1 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d3a9f298f49b9e9950315007667cb10a3e51ffde;p=thirdparty%2Fsamba.git ldb: Avoid inefficient one-level searches Commit 88ae60ed186c9 introduced a problem that made one-level searches inefficient if there were a lot of child objects in the same level, and the requested object didn't exist. Basically, it ignored the case where ldb_kv_index_dn() returned LDB_ERR_NO_SUCH_OBJECT, i.e. the indexed lookup was successful, but didn't find a match. At which point, there was no more processing we needed to do. The behaviour after 88ae60ed186c9 was to fall-through and run the ldb_kv_index_filter() function over *all* the children. This still returned the correct result, but could be costly if there were a lot of children. The case 88ae60ed186c9 was trying to fix was where we could not do an indexed search (e.g. trying to match on a 'attribute=*' filter). In which case we want to ignore the LDB_ERR_OPERATIONS_ERROR and just run ldb_kv_index_filter() over all the children. This is still more efficient than the fallback of doing a full database scan. This patch adds in a short-circuit for the NO_SUCH_OBJECT case, so we can skip the unnecessary ldb_kv_index_filter() work. BUG: https://bugzilla.samba.org/show_bug.cgi?id=13762 Signed-off-by: Tim Beale Reviewed-by: Andrew Bartlett (Manual merge of commit 9a893f9613bd6440ab in master) --- diff --git a/lib/ldb/ldb_tdb/ldb_index.c b/lib/ldb/ldb_tdb/ldb_index.c index 429c8f5aa24..f07c9a818c4 100644 --- a/lib/ldb/ldb_tdb/ldb_index.c +++ b/lib/ldb/ldb_tdb/ldb_index.c @@ -1835,13 +1835,23 @@ int ltdb_search_indexed(struct ltdb_context *ac, uint32_t *match_count) } /* * Here we load the index for the tree. - * - * We only care if this is successful, if the - * index can't trim the result list down then - * the ONELEVEL index is still good enough. */ ret = ltdb_index_dn(ac->module, ltdb, ac->tree, idx_one_tree_list); + + /* + * We can stop if we're sure the object doesn't exist + */ + if (ret == LDB_ERR_NO_SUCH_OBJECT) { + talloc_free(idx_one_tree_list); + talloc_free(dn_list); + return LDB_ERR_NO_SUCH_OBJECT; + } + + /* We only care if this is successful, if the + * index can't trim the result list down then + * the ONELEVEL index is still good enough. + */ if (ret == LDB_SUCCESS) { if (!list_intersect(ldb, ltdb, dn_list,