From c8dbd772f751471fd2824bbb27ac9b8b392af465 Mon Sep 17 00:00:00 2001 From: Howard Chu Date: Sat, 9 Apr 2016 20:42:45 +0100 Subject: [PATCH] mdb_drop optimization If we know there are no sub-DBs and no overflow pages, skip leaf scan. --- libraries/liblmdb/mdb.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c index acab07b829..2d8e458f7e 100644 --- a/libraries/liblmdb/mdb.c +++ b/libraries/liblmdb/mdb.c @@ -10501,8 +10501,11 @@ mdb_drop0(MDB_cursor *mc, int subs) /* DUPSORT sub-DBs have no ovpages/DBs. Omit scanning leaves. * This also avoids any P_LEAF2 pages, which have no nodes. + * Also if the DB doesn't have sub-DBs and has no overflow + * pages, omit scanning leaves. */ - if (mc->mc_flags & C_SUB) + if ((mc->mc_flags & C_SUB) || + (!subs && !mc->mc_db->md_overflow_pages)) mdb_cursor_pop(mc); mdb_cursor_copy(mc, &mx); @@ -10529,6 +10532,9 @@ mdb_drop0(MDB_cursor *mc, int subs) pg, omp->mp_pages); if (rc) goto done; + mc->mc_db->md_overflow_pages -= omp->mp_pages; + if (!mc->mc_db->md_overflow_pages && !subs) + break; } else if (subs && (ni->mn_flags & F_SUBDATA)) { mdb_xcursor_init1(mc, ni); rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0); @@ -10536,6 +10542,8 @@ mdb_drop0(MDB_cursor *mc, int subs) goto done; } } + if (!subs && !mc->mc_db->md_overflow_pages) + goto pop; } else { if ((rc = mdb_midl_need(&txn->mt_free_pgs, n)) != 0) goto done; @@ -10557,6 +10565,7 @@ mdb_drop0(MDB_cursor *mc, int subs) /* no more siblings, go back to beginning * of previous level. */ +pop: mdb_cursor_pop(mc); mc->mc_ki[0] = 0; for (i=1; imc_snum; i++) { -- 2.39.5