| Source | Destination | Time |
|---|---|---|
| LMDB | Dummy | 0:02.72 |
| LMDB | Dummy | 0:02.80 |
| LMDB | Dummy | 0:02.25 |
| LevelDB | Dummy | 0:09.72 |
| LevelDB | Dummy | 0:09.67 |
| LevelDB | Dummy | 0:09.91 |
| LMDB | Dummy | 0:13.63 |
| LevelDB | Dummy | 0:16.14 |
| LMDB | LevelDB | 0:16.88 |
| LMDB | LevelDB | 0:17.22 |
| LMDB | LevelDB | 0:17.49 |
| LMDB | SQLite3 | 0:19.98 |
| LevelDB | LMDB | 0:19.34 |
| LevelDB | LMDB | 0:19.05 |
| LevelDB | LMDB | 0:19.11 |
| SQLite3 | Dummy | 0:20.82 |
| SQLite3 | Dummy | 0:20.85 |
| LMDB | SQLite3 | 0:20.39 |
| SQLite3 | Dummy | 0:21.21 |
| LMDB | SQLite3 | 0:21.17 |
| LMDB | LevelDB | 0:27.67 |
| LevelDB | LMDB | 0:27.58 |
| SQLite3 | LMDB | 0:30.79 |
| LMDB | SQLite3 | 0:31.67 |
| SQLite3 | LMDB | 0:31.56 |
| SQLite3 | LMDB | 0:31.90 |
| SQLite3 | Dummy | 0:32.31 |
| SQLite3 | LevelDB | 0:38.69 |
| SQLite3 | LevelDB | 0:39.08 |
| SQLite3 | LevelDB | 0:39.96 |
| LevelDB | SQLite3 | 0:40.76 |
| LevelDB | SQLite3 | 0:41.22 |
| LevelDB | SQLite3 | 0:42.07 |
| LevelDB | SQLite3 | 0:46.66 |
| SQLite3 | LMDB | 0:50.61 |
| SQLite3 | LevelDB | 1:01.14 |
As you can see, LMDB, performs quite well. The only time LevelDB beats it on read is when you compare LMDB after clearing caches to LevelDB with primed caches. SQLite3's performance is an embarrassment, but it's also the only time we can directly compare LevelDB and LMDB on write. As you can see, SQLite3->LMDB is faster than SQLite3->LevelDB.
For this test, I created all the databases by using emergeblocks on a world with an LMDB backend, then migrated it to the other backends. Before each database was tested, a sync was performed with the caches dropped right after. Since editing world.mt was to happen so often, vi was fired up with that file after the caches were dropped. No sync or crash drop was performed in the middle of the sequence, so the first value is cacheless, while the three after are migrations with the cache primed by the previous run. The command used was a server-mode migration from the database listed to dummy in order to estimate the raw read of the databases.
2016-06-06 23:50:41: ACTION[Main]: Successfully migrated 1483063 blocks 2.42user 0.41system 0:13.63elapsed 20%CPU (0avgtext+0avgdata 499612maxresident)k 432952inputs+32outputs (762major+79373minor)pagefaults 0swaps
2016-06-06 23:50:53: ACTION[Main]: Successfully migrated 1483063 blocks 2.43user 0.28system 0:02.72elapsed 99%CPU (0avgtext+0avgdata 499980maxresident)k 0inputs+8outputs (0major+78099minor)pagefaults 0swaps
2016-06-06 23:51:02: ACTION[Main]: Successfully migrated 1483063 blocks 2.50user 0.29system 0:02.80elapsed 99%CPU (0avgtext+0avgdata 500016maxresident)k 0inputs+32outputs (0major+78098minor)pagefaults 0swaps
2016-06-06 23:51:10: ACTION[Main]: Successfully migrated 1483063 blocks 2.03user 0.21system 0:02.25elapsed 99%CPU (0avgtext+0avgdata 500024maxresident)k 0inputs+8outputs (0major+78099minor)pagefaults 0swaps
2016-06-06 23:51:55: ACTION[Main]: Successfully migrated 1483063 blocks 10.69user 0.34system 0:16.14elapsed 68%CPU (0avgtext+0avgdata 352388maxresident)k 117896inputs+72outputs (229major+78620minor)pagefaults 0swaps
2016-06-06 23:52:14: ACTION[Main]: Successfully migrated 1483063 blocks 9.36user 0.26system 0:09.72elapsed 98%CPU (0avgtext+0avgdata 352960maxresident)k 0inputs+64outputs (0major+78316minor)pagefaults 0swaps
2016-06-06 23:52:30: ACTION[Main]: Successfully migrated 1483063 blocks 9.21user 0.36system 0:09.67elapsed 98%CPU (0avgtext+0avgdata 352960maxresident)k 0inputs+48outputs (0major+78317minor)pagefaults 0swaps
2016-06-06 23:52:48: ACTION[Main]: Successfully migrated 1483063 blocks 9.50user 0.32system 0:09.91elapsed 99%CPU (0avgtext+0avgdata 352860maxresident)k 0inputs+40outputs (0major+78313minor)pagefaults 0swaps
2016-06-06 23:53:45: ACTION[Main]: Successfully migrated 1483063 blocks 13.87user 9.66system 0:32.31elapsed 72%CPU (0avgtext+0avgdata 319616maxresident)k 405192inputs+40outputs (190major+79005minor)pagefaults 0swaps
2016-06-06 23:54:13: ACTION[Main]: Successfully migrated 1483063 blocks 12.16user 8.63system 0:20.82elapsed 99%CPU (0avgtext+0avgdata 320252maxresident)k 0inputs+24outputs (0major+79055minor)pagefaults 0swaps
2016-06-06 23:54:41: ACTION[Main]: Successfully migrated 1483063 blocks 12.06user 8.77system 0:20.85elapsed 99%CPU (0avgtext+0avgdata 320216maxresident)k 0inputs+32outputs (0major+79056minor)pagefaults 0swaps
2016-06-06 23:55:10: ACTION[Main]: Successfully migrated 1483063 blocks 12.69user 8.50system 0:21.21elapsed 99%CPU (0avgtext+0avgdata 320208maxresident)k 0inputs+32outputs (0major+79055minor)pagefaults 0swaps
For the write portion, I migrated from each backend to each other. Once again, caches are dropped before the first, but the remaining three runs occur with the cache primed by the previous run.
2016-06-07 10:12:57: ACTION[Main]: Successfully migrated 1483063 blocks 12.93user 5.26system 0:27.67elapsed 65%CPU (0avgtext+0avgdata 245768maxresident)k 425872inputs+576888outputs (740major+14182minor)pagefaults 0swaps
2016-06-07 10:14:59: ACTION[Main]: Successfully migrated 1483063 blocks 12.71user 5.05system 0:17.22elapsed 103%CPU (0avgtext+0avgdata 247788maxresident)k 208inputs+583288outputs (0major+13104minor)pagefaults 0swaps
2016-06-07 10:16:09: ACTION[Main]: Successfully migrated 1483063 blocks 13.16user 5.25system 0:17.49elapsed 105%CPU (0avgtext+0avgdata 246012maxresident)k 8inputs+578512outputs (0major+12998minor)pagefaults 0swaps
2016-06-07 10:16:58: ACTION[Main]: Successfully migrated 1483063 blocks 13.12user 5.10system 0:16.88elapsed 107%CPU (0avgtext+0avgdata 246028maxresident)k 0inputs+577240outputs (0major+13013minor)pagefaults 0swaps
2016-06-07 10:19:13: ACTION[Main]: Successfully migrated 1483063 blocks 9.93user 0.68system 0:31.67elapsed 33%CPU (0avgtext+0avgdata 227012maxresident)k 426160inputs+368864outputs (740major+11052minor)pagefaults 0swaps
2016-06-07 10:20:21: ACTION[Main]: Successfully migrated 1483063 blocks 9.44user 0.62system 0:21.17elapsed 47%CPU (0avgtext+0avgdata 227428maxresident)k 288inputs+368928outputs (0major+9779minor)pagefaults 0swaps
2016-06-07 10:21:16: ACTION[Main]: Successfully migrated 1483063 blocks 9.51user 0.62system 0:20.39elapsed 49%CPU (0avgtext+0avgdata 227432maxresident)k 104inputs+368912outputs (0major+9780minor)pagefaults 0swaps
2016-06-07 10:22:20: ACTION[Main]: Successfully migrated 1483063 blocks 9.13user 0.49system 0:19.98elapsed 48%CPU (0avgtext+0avgdata 227392maxresident)k 128inputs+368568outputs (0major+9780minor)pagefaults 0swaps
2016-06-07 10:25:40: ACTION[Main]: Successfully migrated 1483063 blocks 14.16user 0.74system 0:27.58elapsed 54%CPU (0avgtext+0avgdata 111584maxresident)k 116944inputs+513800outputs (205major+16562minor)pagefaults 0swaps
2016-06-07 10:26:39: ACTION[Main]: Successfully migrated 1483063 blocks 10.51user 0.40system 0:19.34elapsed 56%CPU (0avgtext+0avgdata 110776maxresident)k 104inputs+394208outputs (1major+16224minor)pagefaults 0swaps
2016-06-07 10:27:39: ACTION[Main]: Successfully migrated 1483063 blocks 10.63user 0.41system 0:19.05elapsed 57%CPU (0avgtext+0avgdata 109036maxresident)k 8inputs+394112outputs (1major+15853minor)pagefaults 0swaps
2016-06-07 10:29:21: ACTION[Main]: Successfully migrated 1483063 blocks 10.83user 0.38system 0:19.11elapsed 58%CPU (0avgtext+0avgdata 104480maxresident)k 0inputs+394136outputs (1major+14707minor)pagefaults 0swaps
2016-06-07 10:32:53: ACTION[Main]: Successfully migrated 1483063 blocks 23.62user 0.80system 0:46.66elapsed 52%CPU (0avgtext+0avgdata 79812maxresident)k 110592inputs+377144outputs (198major+10158minor)pagefaults 0swaps
2016-06-07 10:34:02: ACTION[Main]: Successfully migrated 1483063 blocks 23.54user 0.64system 0:42.07elapsed 57%CPU (0avgtext+0avgdata 80288maxresident)k 136inputs+376792outputs (0major+9962minor)pagefaults 0swaps
2016-06-07 10:35:27: ACTION[Main]: Successfully migrated 1483063 blocks 22.96user 0.61system 0:40.76elapsed 57%CPU (0avgtext+0avgdata 80292maxresident)k 24inputs+376008outputs (0major+9969minor)pagefaults 0swaps
2016-06-07 10:36:35: ACTION[Main]: Successfully migrated 1483063 blocks 22.86user 0.62system 0:41.22elapsed 56%CPU (0avgtext+0avgdata 80276maxresident)k 32inputs+376480outputs (0major+9966minor)pagefaults 0swaps
2016-06-07 10:41:23: ACTION[Main]: Successfully migrated 1483063 blocks 16.38user 11.76system 0:50.61elapsed 55%CPU (0avgtext+0avgdata 40752maxresident)k 396168inputs+365800outputs (165major+8336minor)pagefaults 0swaps
2016-06-07 10:47:30: ACTION[Main]: Successfully migrated 1483063 blocks 13.60user 9.45system 0:31.56elapsed 73%CPU (0avgtext+0avgdata 42860maxresident)k 8inputs+365416outputs (1major+8972minor)pagefaults 0swaps
2016-06-07 10:51:09: ACTION[Main]: Successfully migrated 1483063 blocks 13.08user 9.64system 0:30.79elapsed 73%CPU (0avgtext+0avgdata 42532maxresident)k 0inputs+365376outputs (1major+8974minor)pagefaults 0swaps
2016-06-07 10:52:23: ACTION[Main]: Successfully migrated 1483063 blocks 13.70user 9.78system 0:31.90elapsed 73%CPU (0avgtext+0avgdata 43712maxresident)k 0inputs+365416outputs (1major+9145minor)pagefaults 0swaps
2016-06-07 10:55:11: ACTION[Main]: Successfully migrated 1483063 blocks 29.69user 17.90system 1:01.14elapsed 77%CPU (0avgtext+0avgdata 61004maxresident)k 396376inputs+599200outputs (164major+9970minor)pagefaults 0swaps
2016-06-07 10:56:34: ACTION[Main]: Successfully migrated 1483063 blocks 26.75user 16.13system 0:39.08elapsed 109%CPU (0avgtext+0avgdata 62760maxresident)k 184inputs+599208outputs (0major+10379minor)pagefaults 0swaps
2016-06-07 10:57:35: ACTION[Main]: Successfully migrated 1483063 blocks 27.24user 16.47system 0:39.96elapsed 109%CPU (0avgtext+0avgdata 63236maxresident)k 16inputs+599200outputs (0major+10477minor)pagefaults 0swaps
2016-06-07 10:58:33: ACTION[Main]: Successfully migrated 1483063 blocks 26.26user 16.20system 0:38.69elapsed 109%CPU (0avgtext+0avgdata 61440maxresident)k 16inputs+599184outputs (0major+10067minor)pagefaults 0swaps