我有一个非常简单的测试程序，使用ACKNOWLEDGED批量插入比使用UNACKNOWLEDGED执行速度更快。而且它不仅仅是快一点 - 我看到的因素接近100倍！
我对这两个写问题之间差异的理解仅仅是ACKNOWLEDGED客户端等待服务器确认操作已经执行（但不一定是持久的），而UNACKNOWLEDGED客户端只知道请求发送到线路上。因此，前者实际上可以以更高的速度执行似乎是荒谬的，但这就是我所看到的。
我在64位Windows 7上使用Java驱动程序（v2.12.0）和Oracle JDK v1.7.0_71以及mongo 3.0.0版本。我正在运行mongod ，完全开箱即用（全新安装），无分片或任何东西。在每次测试之前，我确保集合为空并且没有非默认索引。
我很感激能够深入了解为什么我一直看到与我期望相反的东西。
感谢。
这是我的代码：
package test;
import com.mongodb.BasicDBObject;
import com.mongodb.BulkWriteOperation;
import com.mongodb.BulkWriteResult;
import com.mongodb.DBCollection;
import com.mongodb.DBObject;
import com.mongodb.MongoClient;
import com.mongodb.ServerAddress;
import com.mongodb.WriteConcern;
import java.util.Arrays;
public class Test {
private static final int BATCHES = 100;
private static final int BATCH_SIZE = 1000;
private static final int COUNT = BATCHES * BATCH_SIZE;
public static void main(String[] argv) throws Exception {
DBCollection coll = new MongoClient(new ServerAddress()).getDB("test").getCollection("test");
for (String wcName : Arrays.asList("UNACKNOWLEDGED", "ACKNOWLEDGED")) {
WriteConcern wc = (WriteConcern) WriteConcern.class.getField(wcName).get(null);
coll.dropIndexes();
coll.remove(new BasicDBObject());
long start = System.currentTimeMillis();
BulkWriteOperation bulkOp = coll.initializeUnorderedBulkOperation();
for (int i = 1; i < COUNT; i++) {
DBObject doc = new BasicDBObject().append("int", i).append("string", Integer.toString(i));
bulkOp.insert(doc);
if (i % BATCH_SIZE == 0) {
BulkWriteResult results = bulkOp.execute(wc);
if (wc == WriteConcern.ACKNOWLEDGED && results.getInsertedCount() != 1000) {
throw new RuntimeException("Bogus insert count: " + results.getInsertedCount());
}
bulkOp = coll.initializeUnorderedBulkOperation();
}
}
long time = System.currentTimeMillis() - start;
double rate = COUNT / (time / 1000.0);
System.out.printf("%s[w=%s,j=%s]: Inserted %d documents in %s @ %f/sec\n",
wcName, wc.getW(), wc.getJ(), COUNT, duration(time), rate);
}
}
private static String duration(long msec) {
return String.format("%d:%02d:%02d.%03d",
msec / (60 * 60 * 1000),
(msec % (60 * 60 * 1000)) / (60 * 1000),
(msec % (60 * 1000)) / 1000,
msec % 1000);
}
}
这是典型的输出：
UNACKNOWLEDGED[w=0,j=false]: Inserted 100000 documents in 0:01:27.025 @ 1149.095088/sec
ACKNOWLEDGED[w=1,j=false]: Inserted 100000 documents in 0:00:00.927 @ 107874.865156/sec
根据Markus W. Mahlberg的要求，进行更广泛的测试。对于这些测试，我运行了包含四个写入问题的代码：UNACKNOWLEDGED，ACKNOWLEDGED，JOURNALED和FSYNCED。 （我希望这个顺序显示速度下降。）我运行了112次重复，每次重复执行100次1000次插入，每次写入四个问题，每次都进入一个没有索引的空集合。代码与原始帖子相同，但有两个额外的写入问题，输出为CSV格式以便于分析。
UNACKNOWLEDGED和ACKNOWLEDGED之间巨大的倒置性能差异令我感到困惑。
如果有人关心它，那么原始数据就在这里（＆＃34;时间＆＃34;经过100 * 1000次插入已经过了msec;＆＃34;率＆＃34;是docs /秒）：
"UNACK time","UNACK rate","ACK time","ACK rate","JRNL time","JRNL rate","FSYNC time","FSYNC rate"
92815,1077.4120562409094,1348,74183.9762611276,3380,29585.798816568047,3378,29603.31557134399
90209,1108.5368422219512,1303,76745.97083653108,3377,29612.081729345577,3375,29629.62962962963
91089,1097.8273995762386,1319,75815.01137225171,3382,29568.30277942046,3413,29299.73630237328
90159,1109.1516099335618,1320,75757.57575757576,3375,29629.62962962963,3377,29612.081729345577
89922,1112.0749093658949,1315,76045.62737642587,3380,29585.798816568047,3376,29620.853080568722
89997,1111.1481493827573,1306,76569.67840735069,3381,29577.048210588586,3379,29594.55460195324
90141,1109.373093264996,1319,75815.01137225171,3386,29533.372711163614,3378,29603.31557134399
89771,1113.9454835080371,1325,75471.69811320755,3387,29524.65308532625,3521,28401.022436807725
89716,1114.6283828971423,1325,75471.69811320755,3379,29594.55460195324,3379,29594.55460195324
90205,1108.5859985588381,1323,75585.78987150417,3377,29612.081729345577,3376,29620.853080568722
90092,1109.976468498868,1328,75301.2048192771,3382,29568.30277942046,3379,29594.55460195324
89822,1113.3129968159249,1322,75642.965204236,3385,29542.097488921714,3383,29559.562518474726
89821,1113.3253916122064,1310,76335.87786259541,3380,29585.798816568047,3383,29559.562518474726
89945,1111.7905386625162,1318,75872.53414264036,3379,29594.55460195324,3379,29594.55460195324
89917,1112.1367483345753,1352,73964.49704142011,3381,29577.048210588586,3377,29612.081729345577
90358,1106.7088691648773,1303,76745.97083653108,3377,29612.081729345577,3380,29585.798816568047
90187,1108.8072560346836,1348,74183.9762611276,3387,29524.65308532625,3395,29455.081001472754
90634,1103.3387029150208,1322,75642.965204236,3384,29550.827423167848,3381,29577.048210588586
90148,1109.2869503483162,1331,75131.48009015778,3389,29507.22927117144,3381,29577.048210588586
89767,1113.9951207013714,1321,75700.22710068131,3380,29585.798816568047,3382,29568.30277942046
89910,1112.2233344455567,1321,75700.22710068131,3381,29577.048210588586,3385,29542.097488921714
89852,1112.9412812180028,1316,75987.84194528875,3381,29577.048210588586,3401,29403.116730373422
89537,1116.8567184515898,1319,75815.01137225171,3380,29585.798816568047,3380,29585.798816568047
89763,1114.0447623185498,1331,75131.48009015778,3380,29585.798816568047,3382,29568.30277942046
90070,1110.2475852115022,1325,75471.69811320755,3383,29559.562518474726,3378,29603.31557134399
89771,1113.9454835080371,1302,76804.91551459293,3389,29507.22927117144,3378,29603.31557134399
90518,1104.7526458825869,1325,75471.69811320755,3383,29559.562518474726,3380,29585.798816568047
90314,1107.2480457071995,1322,75642.965204236,3380,29585.798816568047,3384,29550.827423167848
89874,1112.6688474976079,1329,75244.54477050414,3386,29533.372711163614,3379,29594.55460195324
89954,1111.6793027547415,1318,75872.53414264036,3381,29577.048210588586,3381,29577.048210588586
89903,1112.3099340400208,1325,75471.69811320755,3379,29594.55460195324,3388,29515.9386068477
89842,1113.0651588343983,1314,76103.500761035,3382,29568.30277942046,3377,29612.081729345577
89746,1114.2557885588217,1325,75471.69811320755,3378,29603.31557134399,3385,29542.097488921714
93249,1072.3975592231552,1327,75357.95026375283,3381,29577.048210588586,3377,29612.081729345577
93638,1067.9425019756936,1331,75131.48009015778,3377,29612.081729345577,3392,29481.132075471698
87775,1139.2765593847905,1340,74626.86567164179,3379,29594.55460195324,3378,29603.31557134399
86495,1156.136192843517,1271,78678.20613690009,3375,29629.62962962963,3376,29620.853080568722
85584,1168.442699570013,1276,78369.90595611285,3432,29137.529137529138,3376,29620.853080568722
86648,1154.094728095282,1278,78247.2613458529,3382,29568.30277942046,3411,29316.91586045148
85745,1166.2487608606916,1274,78492.93563579278,3380,29585.798816568047,3363,29735.355337496283
85813,1165.3246011676551,1279,78186.08287724786,3375,29629.62962962963,3376,29620.853080568722
85831,1165.0802157728558,1288,77639.75155279503,3376,29620.853080568722,3377,29612.081729345577
85807,1165.4060857505797,1259,79428.11755361399,3466,28851.702250432772,3375,29629.62962962963
85964,1163.2776511097668,1258,79491.2559618442,3378,29603.31557134399,3378,29603.31557134399
85854,1164.7680946723508,1257,79554.49482895785,3382,29568.30277942046,3375,29629.62962962963
85787,1165.6777833471272,1257,79554.49482895785,3377,29612.081729345577,3377,29612.081729345577
85537,1169.084723569917,1272,78616.35220125786,3377,29612.081729345577,3377,29612.081729345577
85408,1170.8505058074186,1271,78678.20613690009,3375,29629.62962962963,3425,29197.080291970804
85577,1168.5382754712132,1261,79302.14115781126,3378,29603.31557134399,3375,29629.62962962963
85663,1167.365140142185,1261,79302.14115781126,3377,29612.081729345577,3378,29603.31557134399
85812,1165.3381811401669,1273,78554.59544383347,3377,29612.081729345577,3378,29603.31557134399
85783,1165.7321380693145,1273,78554.59544383347,3377,29612.081729345577,3376,29620.853080568722
85682,1167.106276697556,1280,78125.0,3381,29577.048210588586,3376,29620.853080568722
85753,1166.1399601180133,1260,79365.07936507936,3379,29594.55460195324,3377,29612.081729345577
85573,1168.5928972923703,1332,75075.07507507507,3377,29612.081729345577,3377,29612.081729345577
86206,1160.0120641254668,1263,79176.56373713381,3376,29620.853080568722,3383,29559.562518474726
85593,1168.31983923919,1264,79113.92405063291,3380,29585.798816568047,3378,29603.31557134399
85903,1164.1036983574495,1261,79302.14115781126,3378,29603.31557134399,3377,29612.081729345577
85516,1169.3718134618082,1277,78308.53563038372,3375,29629.62962962963,3376,29620.853080568722
85553,1168.8660830128692,1291,77459.3338497289,3490,28653.295128939826,3377,29612.081729345577
85550,1168.907071887785,1293,77339.52049497294,3379,29594.55460195324,3379,29594.55460195324
85610,1168.0878402055835,1298,77041.60246533128,3384,29550.827423167848,3378,29603.31557134399
85522,1169.2897733916418,1267,78926.59826361484,3379,29594.55460195324,3379,29594.55460195324
85595,1168.2925404521293,1276,78369.90595611285,3379,29594.55460195324,3376,29620.853080568722
85451,1170.2613193526115,1286,77760.49766718507,3376,29620.853080568722,3391,29489.82601002654
85792,1165.609847071988,1252,79872.20447284346,3382,29568.30277942046,3376,29620.853080568722
86501,1156.0559993526085,1255,79681.2749003984,3379,29594.55460195324,3379,29594.55460195324
85718,1166.616113301757,1269,78802.20646178094,3382,29568.30277942046,3376,29620.853080568722
85605,1168.156065650371,1265,79051.38339920949,3378,29603.31557134399,3380,29585.798816568047
85398,1170.9876109510762,1274,78492.93563579278,3377,29612.081729345577,3395,29455.081001472754
86370,1157.809424568716,1273,78554.59544383347,3376,29620.853080568722,3376,29620.853080568722
85905,1164.0765962400326,1280,78125.0,3379,29594.55460195324,3379,29594.55460195324
86020,1162.5203441060219,1285,77821.01167315176,3375,29629.62962962963,3376,29620.853080568722
85726,1166.5072440099852,1272,78616.35220125786,3380,29585.798816568047,3380,29585.798816568047
85628,1167.8422945765403,1270,78740.15748031496,3379,29594.55460195324,3376,29620.853080568722
85989,1162.93944574306,1258,79491.2559618442,3376,29620.853080568722,3378,29603.31557134399
85981,1163.047650062223,1276,78369.90595611285,3376,29620.853080568722,3376,29620.853080568722
86558,1155.2947156819703,1269,78802.20646178094,3385,29542.097488921714,3378,29603.31557134399
85745,1166.2487608606916,1293,77339.52049497294,3378,29603.31557134399,3375,29629.62962962963
85544,1168.9890582624148,1266,78988.94154818325,3376,29620.853080568722,3377,29612.081729345577
85536,1169.0983913206135,1268,78864.35331230283,3380,29585.798816568047,3380,29585.798816568047
85477,1169.9053546568082,1278,78247.2613458529,3388,29515.9386068477,3377,29612.081729345577
85434,1170.4941826439124,1253,79808.45969672786,3378,29603.31557134399,3375,29629.62962962963
85609,1168.1014846569872,1276,78369.90595611285,3364,29726.516052318668,3376,29620.853080568722
85740,1166.316771635176,1258,79491.2559618442,3377,29612.081729345577,3377,29612.081729345577
85640,1167.6786548341897,1266,78988.94154818325,3378,29603.31557134399,3377,29612.081729345577
85648,1167.569587147394,1281,78064.012490242,3378,29603.31557134399,3376,29620.853080568722
85697,1166.9019919017,1287,77700.0777000777,3377,29612.081729345577,3378,29603.31557134399
85696,1166.9156086631815,1256,79617.83439490446,3379,29594.55460195324,3376,29620.853080568722
85782,1165.7457275419085,1258,79491.2559618442,3379,29594.55460195324,3379,29594.55460195324
85837,1164.9987767512844,1264,79113.92405063291,3379,29594.55460195324,3376,29620.853080568722
85632,1167.7877428998504,1278,78247.2613458529,3380,29585.798816568047,3459,28910.089621277824
85517,1169.3581393173288,1256,79617.83439490446,3379,29594.55460195324,3380,29585.798816568047
85990,1162.925921618793,1302,76804.91551459293,3380,29585.798816568047,3377,29612.081729345577
86690,1153.535586572846,1281,78064.012490242,3375,29629.62962962963,3381,29577.048210588586
86045,1162.1825788831425,1274,78492.93563579278,3380,29585.798816568047,3383,29559.562518474726
86146,1160.820003250296,1274,78492.93563579278,3382,29568.30277942046,3418,29256.87536571094
86027,1162.4257500552153,1280,78125.0,3382,29568.30277942046,3381,29577.048210588586
85992,1162.8988743138896,1281,78064.012490242,3376,29620.853080568722,3380,29585.798816568047
85857,1164.727395553071,1288,77639.75155279503,3382,29568.30277942046,3376,29620.853080568722
85853,1164.7816616775185,1284,77881.6199376947,3375,29629.62962962963,3374,29638.41138114997
86069,1161.8585088707896,1295,77220.07722007722,3378,29603.31557134399,3378,29603.31557134399
85842,1164.930919596468,1296,77160.49382716049,3378,29603.31557134399,3376,29620.853080568722
86195,1160.160102094089,1301,76863.95080707148,3376,29620.853080568722,3379,29594.55460195324
85523,1169.2761011657683,1305,76628.35249042146,3376,29620.853080568722,3378,29603.31557134399
85752,1166.1535591006625,1275,78431.37254901961,3374,29638.41138114997,3377,29612.081729345577
85441,1170.3982865369085,1286,77760.49766718507,3377,29612.081729345577,3380,29585.798816568047
85566,1168.6884977678048,1265,79051.38339920949,3377,29612.081729345577,3380,29585.798816568047
85523,1169.2761011657683,1267,78926.59826361484,3377,29612.081729345577,3376,29620.853080568722
86152,1160.7391586962578,1285,77821.01167315176,3374,29638.41138114997,3378,29603.31557134399
85684,1167.0790345922226,1272,78616.35220125786,3378,29603.31557134399,3384,29550.827423167848
86252,1159.3934053703103,1271,78678.20613690009,3376,29620.853080568722,3377,29612.081729345577