Properly update the range of free-list writes when loose pages will be returned to the free-list

Author: kriszyp

dependencies/lmdb/libraries/liblmdb/mdb.c

@@ -4251,7 +4251,7 @@ mdb_freelist_save(MDB_txn *txn)
 				unsigned end = mop_len;
 				mop_len -= len;
 				unsigned start = mop_len > 0 ? mop_len - 1 : 0;
-				char do_write = env->me_freelist_written_start <= end && env->me_freelist_written_end >= start;
+				char do_write = freelist_written_start <= end && freelist_written_end >= start;
 				fl_writes[i++] = do_write;
 				// determine if it is in the range of actively written pages
 				if (freelist_written_start <= end && freelist_written_end >= start) {
@@ -4303,9 +4303,11 @@ mdb_freelist_save(MDB_txn *txn)
 			mop[0] = 0;
 		}
 		mop_len = (mop ? mop[0] : 0) + txn->mt_loose_count;
-		//fprintf(stderr, "mop_len %u = mop[0] %u + txn->mt_loose_count %u, reserved_sape,", mop_len, (mop ? mop[0] : 0), txn->mt_loose_count, reserved_space);
-		if (freelist_written_start != env->me_freelist_written_start)
-		freelist_written_end = env->me_freelist_written_end;
+		if (txn->mt_loose_count > 0) {
+			// loose pages are appended to the end, so we have to expand the range to the end
+			env->me_freelist_written_end = mop_len;
+			env->me_freelist_written_start = 1;
+		}
 	} while(reserved_space != mop_len ||
 		 (start_written > env->me_freelist_start && env->me_freelist_start > 0) ||
 		 freecnt < txn->mt_free_pgs[0] ||
@@ -4317,7 +4319,8 @@ mdb_freelist_save(MDB_txn *txn)
 	 */
 	if (txn->mt_loose_pgs) {
 		MDB_page *mp = txn->mt_loose_pgs;
-		if (!env->me_pghead) env->me_pghead = mdb_midl_alloc(1);
+		if (!env->me_pghead)
+			env->me_pghead = mdb_midl_alloc(1);
 		unsigned count = txn->mt_loose_count;
 		lost_loose += count;
 		for (; mp; mp = NEXT_LOOSE_PAGE(mp))

test/index.test.js

@@ -417,21 +417,37 @@ describe('lmdb-js', function () {
 				//await new Promise((resolve) => setTimeout(resolve, 3000));
 
 				let promise;
+				let deleting;
 				let additive = 'this is more text';
 				for (let i = 0; i < 6; i++) additive += additive;
 				let read_txn = db.useReadTransaction();
-				for (let i = 0; i < 500; i++) {
+				for (let i = 0; i < 5000; i++) {
 					if (Math.random() < 0.3) {
 						read_txn.done();
 						read_txn = db.useReadTransaction();
 					}
 					let text = 'this is a test';
 					while (random() < 0.95) text += additive;
-					if (random() < 0.4) promise = db.remove(i % 40);
-					else promise = db.put(i % 40, text);
+					if (random() < 0.4) promise = db.remove(random());
+					else promise = db.put(random(), text);
 					if (random() < 0.05) {
 						await promise;
 					}
+					if (random() < 0.0001) {
+						if (!deleting) {
+							deleting = true;
+							(async () => {
+								let j = 0;
+								console.log('deleting all entries');
+								for (let { key, value } of db.getRange({})) {
+									let promise = db.remove(key);
+									if (++j % 1000 === 0) await promise;
+								}
+								console.log('finished deleting all entries', j);
+								deleting = false;
+							})();
+						}
+					}
 				}
 				await promise;
 			});