...
分析TsFile文件结构,然后把读取TsFile的耗时步骤进行分解和分类,最后进行实验测量统计。
TsFile结构
TsFile读耗时步骤分解与分类
耗时分类 | 耗时分解 |
(A)get_chunkMetadatas | (A)1_index_read_deserialize_MagicString_FileMetadataSize |
(A)2_index_read_deserialize_IndexRootNode_MetaOffset_BloomFilter | |
(A)3_2_index_read_deserialize_IndexRootNode_exclude_to_TimeseriesMetadata_forExactGet | |
(B)load_on_disk_chunk | (B)4_data_read_deserialize_ChunkHeader |
(B)5_data_read_ChunkData | |
(C)get_pageHeader | (C)6_data_deserialize_PageHeader |
(D-1)decompress_pageData | (D-1)7_1_data_ByteBuffer_to_ByteArray |
(D-1)7_2_data_decompress_PageDataByteArray | |
(D-1)7_3_data_ByteArray_to_ByteBuffer | |
(D-1)7_4_data_split_time_value_Buffer | |
(D-2)decode_pageData | (D-2)8_1_createBatchData |
(D-2)8_2_timeDecoder_hasNext | |
(D-2)8_3_timeDecoder_readLong | |
(D-2)8_4_valueDecoder_read | |
(D-2)8_5_checkValueSatisfyOrNot | |
(D-2)8_6_putIntoBatchData |
...
- 本次实验使用的人工数据集不具有代表性:其 编码压缩效率过低。甚至对于值列来说,和其它编码方式相比,采用PLAIN编码的空间大小是最小的。
- 在中车ZT11529数据集上的实验结果来看:
- 真实数据集的压缩率高、磁盘数据量相对小,此时【从磁盘加载Chunk数据的耗时】小于【解压缩和解码Page数据的耗时】
- D-1步骤内部的耗时瓶颈就是子步骤7_2_data_decompress_PageDataByteArray。注意:人工数据实验里发现另一个子步骤7_1_data_ByteBuffer_to_ByteArray(us)的占比也高,分析是因为人工数据压缩率很低,子步骤7_2_data_decompress_PageDataByteArray(us)耗时相对少,从而7_1_data_ByteBuffer_to_ByteArray(us)耗时占比相对偏高。
- D-1解压缩和D-2解码的空间压缩关系和耗时关系还有待探索
- 写数据的耗时可以也测量一下
- 注意RLE编码对于浮点数是有损的
实验设置
IoTDB版本
- v0.13.1
实验环境
- CPU:Intel(R) Core(TM) i7-8700 CPU @ 3.20GHz,(6核12线程)
- L1 cache 284KB, L2 cache 1536KB, L3 cache 12MB
- 内存:16G
- 硬盘:1.8T HDD /dev/sdb1 mounted on /disk
- 操作系统:Ubuntu 16.04.7 LTS
...
工具地址:
WRITE_READ_JAR_PATH
:RLTsFileReadCostBench-0.13.1-jar-with-dependencies.jar的地址Calculator_JAR_PATH
:把若干次重复读实验结果进行平均值和百分比统计计算的RLRepeatReadResultAvgPercCalculator-0.13.1-jar-with-dependencies.jar的地址TOOL_PATH
:用于替换脚本中变量值的自动脚本工具RLtool.sh的地址READ_SCRIPT_PATH
:RLReadExpScripts.sh的地址
写数据参数:见RLTsFileReadCostBench写数据参数
读数据参数:见RLTsFileReadCostBench读数据参数
REPEAT
:读实验重复次数
输出:不同压缩方式下的一个TsFile文件、一个TsFile空间统计结果文件(
*writeResult.csv
)、REPEAT个读TsFile耗时结果csv文件(*readResult-T*csv
)、一个把重复读实验结果横向拼接起来的csv文件(*readResult-combined.csv
)、一个把写结果和读结果拼接起来的csv文件(*allResult-combined.csv
)、一个把读结果取平均值并且按照不同粒度统计百分比的csv文件(*allResult-combined-processed.csv
其它类似,不再赘述。
...
实验具体结果
中车数据实验结果
改变压缩方式
RLCompressionRealExpScripts.sh
压缩方式 | GZIP | LZ4 | SNAPPY | UNCOMPRESSED |
dataset | /disk/rl/zc_data/ZT11529.csv | /disk/rl/zc_data/ZT11529.csv | /disk/rl/zc_data/ZT11529.csv | /disk/rl/zc_data/ZT11529.csv |
pagePointNum(ppn) | 10000 | 10000 | 10000 | 10000 |
numOfPagesInChunk(pic) | 100 | 100 | 100 | 100 |
chunksWritten(cw) | 13 | 13 | 13 | 13 |
timeEncoding(te) | TS_2DIFF | TS_2DIFF | TS_2DIFF | TS_2DIFF |
valueDataType(vt) | DOUBLE | DOUBLE | DOUBLE | DOUBLE |
valueEncoding(ve) | GORILLA | GORILLA | GORILLA | GORILLA |
compression(co) | GZIP | LZ4 | SNAPPY | UNCOMPRESSED |
totalPointNum | 12780287 | 12780287 | 12780287 | 12780287 |
tsfileSize(MB) | 19.34862614 | 23.77741051 | 23.15641212 | 36.30773735 |
chunkDataSize_stats_mean(MB) | 1.515139659 | 1.86007007 | 1.813184341 | 2.837062438 |
compressedPageSize_stats_mean(B) | 15824.16667 | 19440.275 | 18948.69 | 29684.7575 |
uncompressedPageSize_stats_mean(B) | 29684.7575 | 29684.7575 | 29684.7575 | 29684.7575 |
timeBufferSize_stats_mean(B) | 11461.4625 | 11461.4625 | 11461.4625 | 11461.4625 |
valueBufferSize_stats_mean(B) | 18221.26833 | 18221.26833 | 18221.26833 | 18221.26833 |
[2] category: (A)get ChunkStatistic->(B)load on-disk Chunk->(C)get PageStatistics->(D)load in-memory PageData | ||||
[Avg&Per] (A)get_chunkMetadatas | 87316.85010000001 us - 8.19883087518919% | 100289.6416 us - 12.59103802007131% | 89466.6045 us - 11.199530364576052% | 88760.777 us - 10.335699109318087% |
[Avg&Per] (B)load_on_disk_chunk | 160699.6025 us - 15.089285299443361% | 176784.88239999997 us - 22.19476647997349% | 105802.9384 us - 13.244531050378352% | 191518.85280000002 us - 22.301305860612082% |
[Avg&Per] (C)get_pageHeader | 2436.5129999999995 us - 0.22878239411203669% | 2198.3668000000007 us - 0.27599779517870476% | 2319.9517000000005 us - 0.29041416798711567% | 3134.228800000001 us - 0.3649635223062446% |
[Avg&Per] (D_1)decompress_pageData | 356587.5454999999 us - 33.482666568996265% | 31158.160799999983 us - 3.911805656191469% | 115629.7179 us - 14.474658381255693% | 29640.983400000016 us - 3.4515277590088287% |
[Avg&Per] (D_2)decode_pageData | 457950.96670000016 us - 43.000434862259155% | 486085.0215000002 us - 61.02639204858503% | 485623.25309999986 us - 60.790866035802786% | 545723.8052999998 us - 63.54650374875476% |
SUM | 1064991.4778 us | 796516.0731000002 us | 798842.4655999999 us | 858778.6472999998 us |
[3] D_1 compare each step inside | ||||
[Avg&Per] (D-1)7_1_data_ByteBuffer_to_ByteArray(us) | 1269.7615999999996 us - 0.36377892330196115% | 1808.5776999999991 us - 7.207505165727991% | 1687.9916000000003 us - 1.412377327892232% | 3197.6313 us - 41.86667970732365% |
[Avg&Per] (D-1)7_2_data_decompress_PageDataByteArray(us) | 345856.23130000004 us - 99.08569249502276% | 21247.39440000001 us - 84.67466169480036% | 116100.69619999993 us - 97.14384305311928% | 2432.4552000000012 us - 31.84820675254647% |
[Avg&Per] (D-1)7_3_data_ByteArray_to_ByteBuffer(us) | 374.18470000000025 us - 0.10720162531460037% | 442.10720000000003 us - 1.761876157051776% | 424.26030000000026 us - 0.35498732863644405% | 421.1930000000002 us - 5.51469221169019% |
[Avg&Per] (D-1)7_4_data_split_time_value_Buffer(us) | 1547.4220999999993 us - 0.443326956360674% | 1594.8989000000004 us - 6.355956982419887% | 1301.2614999999998 us - 1.0887922903520593% | 1586.372500000001 us - 20.770421328439692% |
[3] D_2 compare each step inside | ||||
[Avg&Per] (D-2)8_1_createBatchData(us) | 3430.8672 us - 0.22855030377902266% | 4174.8958 us - 0.275155541260775% | 3438.1465 us - 0.22874736939899784% | 3730.6205 us - 0.24721094086707432% |
[Avg&Per] (D-2)8_2_timeDecoder_hasNext(us) | 234016.77980000002 us - 15.589238228946503% | 236135.9462 us - 15.56305048087338% | 235278.4135 us - 15.65358490817499% | 234469.6457 us - 15.537217392727715% |
[Avg&Per] (D-2)8_3_timeDecoder_readLong(us) | 357893.9434 us - 23.841426880277478% | 360253.1425 us - 23.743262865502565% | 358341.1524 us - 23.84121675993312% | 363063.0738 us - 24.058508247673558% |
[Avg&Per] (D-2)8_4_valueDecoder_read(us) | 353821.6809 us - 23.570149451806063% | 359477.8899 us - 23.692168165422427% | 356440.4841 us - 23.714761161335133% | 355773.1939 us - 23.5754416723178% |
[Avg&Per] (D-2)8_5_checkValueSatisfyOrNot(us) | 223758.3096 us - 14.905861011513531% | 224938.2721 us - 14.825043539994219% | 224282.1638 us - 14.921980483485841% | 226053.6587 us - 14.979528915812129% |
[Avg&Per] (D-2)8_6_putIntoBatchData(us) | 328221.5562 us - 21.864774123677403% | 332305.597 us - 21.90131940694663% | 325251.7878 us - 21.639709317671908% | 325993.7043 us - 21.602092830601723% |
...
补充实验
时间戳和值都使用PLAIN编码,然后改变压缩。
RLValueEncodingRealExpScriptsRLCompressionRealExpScripts.sh
编码方式压缩方式 | GORILLAGZIP | PLAINLZ4 | RLESNAPPY | TS_2DIFFUNCOMPRESSED | |||
dataset | /disk/rl/zc_data/ZT11529.csv | /disk/rl/zc_data/ZT11529.csv | /disk/rl/zc_data/ZT11529.csv | /disk/rl/zc_data/ZT11529.csv | |||
pagePointNum(ppn) | 10000 | 10000 | 10000 | 10000 | |||
numOfPagesInChunk(pic) | 100 | 100 | 100 | 100 | |||
chunksWritten(cw) | 13 | 13 | 13 | 13 | |||
timeEncoding(te) | TS_2DIFF | TS_2DIFF | TS_2DIFF | PLAIN | PLAIN | PLAIN | PLAINTS_2DIFF |
valueDataType(vt) | DOUBLE | DOUBLE | DOUBLE | DOUBLE | |||
valueEncoding(ve) | GORILLAPLAIN | PLAIN | RLEPLAIN | TS_2DIFFPLAIN | |||
compression(co) | SNAPPYGZIPSNAPPY | LZ4 | SNAPPYSNAPPY | UNCOMPRESSED | |||
totalPointNum | 12780287 | 12780287 | 12780287 | 12780287 | |||
tsfileSize(MB) | 2350.156412127578783 | 2674.5996017571146107 | 2275.1014785881546879 | 20195.985507970946026 | |||
chunkDataSize_stats_mean(MB) | 13.813184341977135579 | 5.846096277 | 5.932730039 | 15.26517868 | |||
compressedPageSize_stats_mean(B) | 41639.28917 | 61236.7625 | 62145.18333 | 160003 | |||
uncompressedPageSize_stats_mean(B) | 160003 | 160003 | 160003 | 160003 | |||
timeBufferSize_stats_mean(B) | 80000 | 80000 | 80000 | 80000 | |||
valueBufferSize_stats_mean(B) | 80000 | 80000 | 80000 | 80000 | |||
total_time(us) | 2096685.5981 | 1244193.0404 | 1195582.1173 | 1895095.384 | |||
[2] category: (A)get ChunkStatistic->(B)load on-disk Chunk->(C)get PageStatistics->(D)load in-memory PageData | |||||||
[Avg&Per] (A)get_chunkMetadatas | 86791.3859 us - 4.1844839300349514% | 100869.9527 us - 8.731470875680406% | 99547.05960000001 us - 7.911992556094877% | 88166.6213 us - 4.659966496653105% | |||
[Avg&Per] (B)load_on_disk_chunk | 349328.55549999996 us - 16.84222128306944% | 452828.32 us - 39.197572537012675% | 450015.7795 us - 35.76721916082827% | 1155773.8993 us - 61.08737716190697% | |||
[Avg&Per] (C)get_pageHeader | 2818.293900000001 us - 0.13587875585087916% | 3913.898699999998 us - 0.3387935811871694% | 3502.114700000002 us - 0.27834780402685505% | 4450.306 us - 0.23521687180559223% | |||
[Avg&Per] (D_1)decompress_pageData | 1350175.8349000001 us - 65.09619618668371% | 261417.90119999985 us - 22.628768326063632% | 395144.6617 us - 31.40606698493612% | 173785.97769999996 us - 9.185299626198828% | |||
[Avg&Per] (D_2)decode_pageData | 285009.94010000007 us - 13.74121984436101% | 336215.7518000001 us - 29.103394680056127% | 309969.7735 us - 24.636373494113883% | 469824.3798999997 us - 24.832139843435506% | |||
SUM | 2074124.0103 | 1155245.8243999998 | 1258179.389 | 1892001.1841999996 | |||
[3] D_1 compare each step inside | |||||||
[Avg&Per] (D-1)7_1_data_ByteBuffer_to_ByteArray(us) | 4312.080999999998 us - 0.3365746911741179% | 10247.3701 us - 5.205625954425964% | 9355.254500000003 us - 2.648386471251286% | 33088.566800000015 us - 56.71920599957147% | |||
[Avg&Per] (D-1)7_2_data_decompress_PageDataByteArray(us) | 1274619.9271000002 us - 99.48904214184739% | 183796.93149999995 us - 93.36815862249874% | 341381.81159999996 us - 96.64204980983628% | 21318.842899999996 us - 36.54397754446109% | |||
[Avg&Per] (D-1)7_3_data_ByteArray_to_ByteBuffer(us) | 454.68920000000026 us - 0.03549026028736633% | 659.1047999999998 us - 0.334822790636471% | 604.4583000000001 us - 0.17111658310904862% | 973.5250000000001 us - 1.6687808013713306% | |||
[Avg&Per] (D-1)7_4_data_split_time_value_Buffer(us) | 1779.4489000000008 us - 0.1388929066911369% | 2148.4263999999994 us - 1.091392632438828% | 1902.0298000000007 us - 0.5384471358033915% | 2956.5653000000016 us - 5.068035654596102% | |||
[3] D_2 compare each step inside | |||||||
[Avg&Per] (D-2)8_1_createBatchData(us) | 3343.3923 us - 0.259976288059772% | 3522.578 us - 0.27212097540020236% | 3458.9225 us - 0.2672966393395521% | 3730.5984 us - 0.2816327187407449% | |||
[Avg&Per] (D-2)8_2_timeDecoder_hasNext(us) | 232202.511 us - 18.05565768873081% | 231677.2947 us - 17.897191037883086% | 231911.8133 us - 17.921548782382853% | 237390.8697 us - 17.921263258420133% | |||
[Avg&Per] (D-2)8_3_timeDecoder_readLong(us) | 254086.67 us - 19.75733129255225% | 255389.3804 us - 19.72896194244707% | 255976.5501 us - 19.78120978179259% | 261059.1494 us - 19.70804415658043% | |||
[Avg&Per] (D-2)8_4_valueDecoder_read(us) | 241634.0221 us - 18.78903535624908% | 242640.7293 us - 18.744122040429612% | 242328.9765 us - 18.726560376256852% | 246610.5964 us - 18.6172847590372% | |||
[Avg&Per] (D-2)8_5_checkValueSatisfyOrNot(us) | 230100.908 us - 17.892240746329144% | 231053.5736 us - 17.849008259784295% | 231043.8535 us - 17.85447508020484% | 235200.0462 us - 17.755872210542634% | |||
[Avg&Per] (D-2)8_6_putIntoBatchData(us) | 324669.8983 us - 25.24575862807894% | 330206.1447 us - 25.508595744055732% | 329318.78729999997 us - 25.448909340023306% | 340641.1962 us - 25.715902896678855% |
- 可以看到,当时间戳列和值列都使用PLAIN编码之后,压缩负责了全部的压缩率,此时D-1操作和耗时占比有了明显提高;但是也可以看到,即便如此,除了GZIP之外的压缩方式的D-1耗时占比也没有增大到60%以上,D-2解码操作仍然有不小的基础耗时
改变值列编码方式
RLValueEncodingRealExpScripts.sh
编码方式 | GORILLA | PLAIN | RLE | TS_2DIFF |
dataset | /disk/rl/zc_data/ZT11529.csv | /disk/rl/zc_data/ZT11529.csv | /disk/rl/zc_data/ZT11529.csv | /disk/rl/zc_data/ZT11529.csv |
pagePointNum(ppn) | 10000 | 10000 | 10000 | 10000 |
numOfPagesInChunk(pic) | 100 | 100 | 100 | 100 |
chunksWritten(cw) | 13 | 13 | 13 | 13 |
timeEncoding(te) | TS_2DIFF | TS_2DIFF | TS_2DIFF | TS_2DIFF |
valueDataType(vt) | DOUBLE | DOUBLE | DOUBLE | DOUBLE |
valueEncoding(ve) | GORILLA | PLAIN | RLE | TS_2DIFF |
compression(co) | SNAPPY | SNAPPY | SNAPPY | SNAPPY |
totalPointNum | 12780287 | 12780287 | 12780287 | 12780287 |
tsfileSize(MB) | 23.15641212 | 26.59960175 | 22.10147858 | 20.98550797 |
chunkDataSize_stats_mean(MB) | 1.813184341 | 2.081166744 | 1.740072568 | 1.642661015 |
compressedPageSize_stats_mean(B) | 18948.69 | 21758.61667 | 18182.29917 | 17160.8925 |
uncompressedPageSize_stats_mean(B) | 29684.7575 | 91463.48917 | 25245.93417 | 22210.36417 |
timeBufferSize_stats_mean(B) | 11461.4625 | 11461.4625 | 11461.4625 | 11461.4625 |
valueBufferSize_stats_mean(B) | 18221.26833 | 80000 | 13782.445 | 10746.875 |
[2] category: (A)get ChunkStatistic->(B)load on-disk Chunk->(C)get PageStatistics->(D)load in-memory PageData | ||||
[Avg&Per] (A)get_chunkMetadatas | 88753.03020000001 us - 11.21274000219672% | 97256.88870000001 us - 12.181751942467722% | 84509.5108 us - 9.498496964807579% | 86370.7961 us - 11.6687579647861% |
[Avg&Per] (B)load_on_disk_chunk | 105215.9241 us - 13.29260306229143% | 138228.6108 us - 17.313597737139155% | 139816.5536 us - 15.714765088895252% | 96826.5282 us - 13.081335047881257% |
[Avg&Per] (C)get_pageHeader | 2352.1583 us - 0.2971632563133493% | 2625.5312999999983 us - 0.328856613051254% | 3388.6254999999987 us - 0.38086658793698225% | 3159.255499999999 us - 0.4268177375109232% |
[Avg&Per] (D_1)decompress_pageData | 114457.26139999992 us - 14.460120522641777% | 182862.35910000015 us - 22.904124612107367% | 155021.76800000004 us - 17.42376424722015% | 120684.50350000002 us - 16.304565026949902% |
[Avg&Per] (D_2)decode_pageData | 480759.0216999998 us - 60.73737315655672% | 377408.39589999994 us - 47.27166909523449% | 506978.10549999995 us - 56.982107111140046% | 433147.3443000001 us - 58.51852422287182% |
SUM | 791537.3956999998 us | 798381.7858000002 us | 889714.5634 us | 740188.4276000002 |
[3] D_1 compare each step inside | ||||
[Avg&Per] (D-1)7_1_data_ByteBuffer_to_ByteArray(us) | 1754.3673999999999 us - 1.6860113426598728% | 2320.3632000000002 us - 1.489795195953362% | 1825.1960999999988 us - 1.548613686329812% | 1607.3271999999997 us - 1.758246074195737% |
[Avg&Per] (D-1)7_2_data_decompress_PageDataByteArray(us) | 100527.56879999992 us - 96.61067644486589% | 151532.73299999998 us - 97.29198327791244% | 113686.73430000001 us - 96.4591326329927% | 87212.82 us - 95.4016073295714% |
[Avg&Per] (D-1)7_3_data_ByteArray_to_ByteBuffer(us) | 431.9958999999999 us - 0.41516388607230165% | 468.2119000000003 us - 0.30061666178303303% | 474.28859999999975 us - 0.4024169332984032% | 663.3730000000002 us - 0.7256599483773118% |
[Avg&Per] (D-1)7_4_data_split_time_value_Buffer(us) | 1340.373799999999 us - 1.288148326401935% | 1429.1740000000002 us - 0.9176048643511714% | 1873.7816000000007 us - 1.5898367473790769% | 1932.989900000001 us - 2.1144866478555286% |
[3] D_2 compare each step inside | ||||
[Avg&Per] (D-2)8_1_createBatchData(us) | 3348.9259 us - 0.2218271110091239% | 3442.3069 us - 0.24318767981262365% | 3466.6887 us - 0.22277034162258696% | 3338.6453 us - 0.22194982158403212% |
[Avg&Per] (D-2)8_2_timeDecoder_hasNext(us) | 235317.741 us - 15.587043790733997% | 244839.8323 us - 17.29713023052909% | 239308.8755 us - 15.37805224577913% | 240223.005 us - 15.969786637750962% |
[Avg&Per] (D-2)8_3_timeDecoder_readLong(us) | 361562.5392 us - 23.949282819264262% | 363364.4154 us - 25.67050285597614% | 362143.5815 us - 23.271443255687238% | 357833.1113 us - 23.788389623148674% |
[Avg&Per] (D-2)8_4_valueDecoder_read(us) | 356325.4946 us - 23.602389962111484% | 241625.5526 us - 17.07005192367858% | 396438.5566 us - 25.475247513902037% | 335421.7093 us - 22.298501890735768% |
[Avg&Per] (D-2)8_5_checkValueSatisfyOrNot(us) | 225554.2633 us - 14.940327764084076% | 232364.86419999998 us - 16.415814695306036% | 224510.63450000001 us - 14.4271133273284% | 230332.4743 us - 15.312273986066641% |
[Avg&Per] (D-2)8_6_putIntoBatchData(us) | 327591.9399 us - 21.699128552797042% | 329856.9807 us - 23.30331261469754% | 330303.223 us - 21.225373315680617% | 337085.3345 us - 22.409098040713936% |
...
...
改变值列编码方式
RLValueEncodingSynExpScripts.sh
...