「YashanDB个人版体验」崖山数据库这一点比达梦强

Roger的数据库专栏 2023-11-18

792

前面提到过达梦数据库不支持多块写，会导致一定程度写放大问题。那么崖山数据库是否支持呢？带着这个疑问我们来简单测一测，看看是否有什么新的发现。

首先创建个测试表：

SQL> create table test1 as select * from t17 where 1=2;


Succeed.


Elapsed: 00:00:00.009
SQL> insert into test1 select * from t17 where rownum < 10000;


9999 rows affected.


Elapsed: 00:00:00.036
SQL> commit;


Succeed.


Elapsed: 00:00:00.001
SQL> alter system switch logfile;


Succeed.


Elapsed: 00:00:00.028
SQL> 
SQL> select name,THREAD_ID from v$process where name='DBWR';


NAME                                          THREAD_ID 
--------------------------------- --------------------- 
DBWR                                               8526
DBWR                                               8527

在insert数据时我们就可以同时打开strace和blktrace进行简单跟踪。

[root@yashandb1 ~]# strace -fr -o tmp/8518.log  -p 8518
strace: Process 8518 attached with 55 threads
^Cstrace: Process 8518 detached
strace: Process 8520 detached
strace: Process 8521 detached
strace: Process 8522 detached
strace: Process 8523 detached
......
[root@yashandb1 ~]# cat tmp/8518.log|grep 8526|grep 'pwrite64(4'
8526       0.000033 pwrite64(48, "s\300\216D[\0\0\0\332\35\1\0\0\0\0\0\200!\0\0\4\0\0\0\0\0\0\0\0\0\0\0"..., 8192, 1097728) = 8192
8526       0.000188 pwrite64(48, "2\212\16[v\0\0\0\332\35\1\0\0\0\0\0@E\0\0\4\0\0\0R\0\0\0\0\0\0\0"..., 8192, 2269184) = 8192
8526       0.000169 pwrite64(48, "\310(s\312!\1\0\0\332\35\1\0\0\0\0\0\0G\0\0\v\0\0\0\0\4\0\0\0\0\0\0"..., 8192, 2326528) = 8192
8526       0.000265 pwrite64(49, "\267\227\226h\23\t\0\0\331\35\1\0\0\0\0\0@~\2\0\7\0\0\0@X\6\0\200X\6\0"..., 16384, 20914176) = 16384
8526       0.000173 pwrite64(49, "\330\206ZE\33\t\0\0\352\35\1\0\0\0\0\0\200\226\2\0\7\0\0\0@\\\6\0\200]\6\0"..., 16384, 21708800) = 16384
8526       0.000206 pwrite64(49, "<\245\370\320\266\0\0\0\331\35\1\0\0\0\0\0@X\6\0\10\0\0\0\200X\6\0\0X\6\0"..., 16384, 53223424 <unfinished ...>
8526       0.000069 pwrite64(49, "7\332\254\300\246\0\0\0\352\35\1\0\0\0\0\0@\\\6\0\10\0\0\0\200\\\6\0\0\\\6\0"..., 49152, 53354496) = 49152
[root@yashandb1 ~]# 
[root@yashandb1 ~]# cat tmp/8518.log|grep 8526|grep 'pwrite64(5'
8526       0.000178 pwrite64(50, "L\31qU\\\2\0\0\350\35\1\0\0\0\0\0\200\0\0\0\t\0\0\0\200\0\0\0 \0\0\0"..., 8192, 16384) = 8192
8526       0.000168 pwrite64(50, "Q$\2250\35\0\0\0\333\35\1\0\0\0\0\0\0$\25\0 \0\0\0\361\10\0\0\0\0\0\0"..., 1064960, 177340416 <unfinished ...>
8526       0.000034 pwrite64(50, "O\233\236\305\5\0\0\0\353\35\1\0\0\0\0\0\0L\25\0\4\0\0\0\361\10\0\0\0\0\0\0"..., 131072, 178651136) = 131072

8526 为DBWR线程，从该线程的写情况来看，肯定是进行了IO 合并，有大于8192的情况，由此可见崖山数据库可以实现多块写的。这一点看上去比达梦强。解析来看看blktrace的情况。

[root@yashandb1 ~]# blktrace -d  dev/sda2
^C=== sda2 ===
  CPU  0:                   20 events,        1 KiB data
  CPU  1:                  268 events,       13 KiB data
  CPU  2:                  200 events,       10 KiB data
  CPU  3:                  319 events,       15 KiB data
  CPU  4:                   39 events,        2 KiB data
  CPU  5:                   67 events,        4 KiB data
  CPU  6:                    0 events,        0 KiB data
  CPU  7:                  232 events,       11 KiB data
  Total:                  1145 events (dropped 0),       54 KiB data
[root@yashandb1 ~]# 


[root@yashandb1 ~]# ls -ltr
total 72
-rw-------. 1 root root  1547 Sep  8 15:23 anaconda-ks.cfg
-rw-r--r--  1 root root  1872 Nov 17 15:35 sda2.blktrace.4
-rw-r--r--  1 root root  3216 Nov 17 15:35 sda2.blktrace.5
-rw-r--r--  1 root root 15344 Nov 17 15:35 sda2.blktrace.3
-rw-r--r--  1 root root 12864 Nov 17 15:35 sda2.blktrace.1
-rw-r--r--  1 root root  9632 Nov 17 15:35 sda2.blktrace.2
-rw-r--r--  1 root root     0 Nov 17 15:35 sda2.blktrace.6
-rw-r--r--  1 root root   960 Nov 17 15:35 sda2.blktrace.0
-rw-r--r--  1 root root 11160 Nov 17 15:35 sda2.blktrace.7

先合并一下trace文件：

[root@yashandb1 ~]# blkparse -i sda2 -d sda2.blktrace_all.parse
Input file sda2.blktrace.0 added
Input file sda2.blktrace.1 added
Input file sda2.blktrace.2 added
Input file sda2.blktrace.3 added
Input file sda2.blktrace.4 added
Input file sda2.blktrace.5 added
Input file sda2.blktrace.7 added
  8,2    4        1     0.000000000  8853  A WSM 155225656 + 11 <- (253,0) 52479544
  ......
  8,2    1       24    10.626109698  8601  A WSM 59645959 + 3 <- (253,2) 43128839
  8,0    1       25    10.626110199  8601  A WSM 61745159 + 3 <- (8,2) 59645959
  8,2    1       26    10.626111104  8601  Q WSM 61745159 + 3 [WORKER]
  8,2    1       27    10.626114549  8601  G WSM 61745159 + 3 [WORKER]
  8,2    1       28    10.626115504  8601  P   N [WORKER]
  8,2    1       29    10.626117038  8601  I WSM 61745159 + 3 [WORKER]
  8,2    1       30    10.626118441  8601  U   N [WORKER] 1
  8,2    1       31    10.626119634  8601  D WSM 61745159 + 3 [WORKER]
  8,2    1       32    10.626502054     0  C WSM 61745159 + 3 [0]
  8,2    1       33    10.694865061  8526  A  WS 59708832 + 16 <- (253,2) 43191712
  8,0    1       34    10.694865615  8526  A  WS 61808032 + 16 <- (8,2) 59708832
  8,2    1       35    10.694867479  8526  Q  WS 61808032 + 16 [DBWR]
  8,2    1       36    10.694874606  8526  G  WS 61808032 + 16 [DBWR]
  8,2    1       37    10.694876718  8526  I  WS 61808032 + 16 [DBWR]
  8,2    1       38    10.694884953  8526  D  WS 61808032 + 16 [DBWR]
  8,2    1       39    10.695360057     0  C  WS 61808032 + 16 [0]
  。。。。。。
  8,2    1       76    10.703242985  8526  P   N [DBWR]
  8,2    1       77    10.703244501  8526  I WSM 61745166 + 2 [DBWR]
  8,2    1       78    10.703245707  8526  U   N [DBWR] 1
  8,2    1       79    10.703246974  8526  D WSM 61745166 + 2 [DBWR]
  8,2    1       80    10.706622914     0  C WSM 61745166 + 2 [0]
  8,2    4       10    10.816649391  8549  A  WS 59975312 + 1024 <- (253,2) 43458192
  8,0    4       11    10.816650253  8549  A  WS 62074512 + 1024 <- (8,2) 59975312
  8,2    4       12    10.816651893  8549  Q  WS 62074512 + 1024 [LOGW]
  8,2    4       13    10.816658488  8549  G  WS 62074512 + 1024 [LOGW]
  8,2    4       14    10.816662631  8549  I  WS 62074512 + 1024 [LOGW]
  8,2    4       15    10.816665962  8549  D  WS 62074512 + 1024 [LOGW]
  8,2    4       16    10.816971184  8549  A  WS 59976336 + 928 <- (253,2) 43459216
  8,0    4       17    10.816971856  8549  A  WS 62075536 + 928 <- (8,2) 59976336
  8,2    4       18    10.816972440  8549  Q  WS 62075536 + 928 [LOGW]
  8,2    4       19    10.816974592  8549  G  WS 62075536 + 928 [LOGW]
  8,2    4       20    10.816977368  8549  I  WS 62075536 + 928 [LOGW]
  8,2    4       21    10.816978702  8549  D  WS 62075536 + 928 [LOGW]
  8,2    4       22    10.818415682     0  C  WS 62074512 + 1024 [0]
  8,2    4       23    10.819062222     0  C  WS 62075536 + 928 [0]
  8,2    4       24    10.819259454  8549  A WSM 59645968 + 2 <- (253,2) 43128848
  8,0    4       25    10.819259892  8549  A WSM 61745168 + 2 <- (8,2) 59645968
  8,2    4       26    10.819260600  8549  Q WSM 61745168 + 2 [LOGW]
  8,2    4       27    10.819264185  8549  G WSM 61745168 + 2 [LOGW]
  8,2    4       28    10.819265071  8549  P   N [LOGW]
  8,2    4       29    10.819266604  8549  I WSM 61745168 + 2 [LOGW]
  8,2    4       30    10.819268084  8549  U   N [LOGW] 1
  8,2    4       31    10.819269364  8549  D WSM 61745168 + 2 [LOGW]
  8,2    4       32    10.819584068     0  C WSM 61745168 + 2 [0]
  8,2    0        1    12.602087677  8601  A  WS 59977264 + 24 <- (253,2) 43460144
  8,0    0        2    12.602088652  8601  A  WS 62076464 + 24 <- (8,2) 59977264
  8,2    0        3    12.602090340  8601  Q  WS 62076464 + 24 [WORKER]
  8,2    0        4    12.602098398  8601  G  WS 62076464 + 24 [WORKER]
  8,2    0        5    12.602101846  8601  I  WS 62076464 + 24 [WORKER]
  8,2    0        6    12.602105695  8601  D  WS 62076464 + 24 [WORKER]
  8,2    0        7    12.602600077     0  C  WS 62076464 + 24 [0]
  8,2    0        8    12.602672057  8601  A WSM 59645970 + 2 <- (253,2) 43128850
  8,0    0        9    12.602672518  8601  A WSM 61745170 + 2 <- (8,2) 59645970
  8,2    0       10    12.602673199  8601  Q WSM 61745170 + 2 [WORKER]
  8,2    0       11    12.602676484  8601  G WSM 61745170 + 2 [WORKER]
  8,2    0       12    12.602677299  8601  P   N [WORKER]
  8,2    0       13    12.602678762  8601  I WSM 61745170 + 2 [WORKER]
  8,2    0       14    12.602680119  8601  U   N [WORKER] 1
  8,2    0       15    12.602681215  8601  D WSM 61745170 + 2 [WORKER]
  8,2    0       16    12.602975795     0  C WSM 61745170 + 2 [0]
  8,2    1       81    13.706853536  8526  A  WS 59708816 + 16 <- (253,2) 43191696
  8,0    1       82    13.706854365  8526  A  WS 61808016 + 16 <- (8,2) 59708816
  8,2    1       83    13.706856222  8526  Q  WS 61808016 + 16 [DBWR]
  8,2    1       84    13.706863355  8526  G  WS 61808016 + 16 [DBWR]
  8,2    1       85    13.706865911  8526  I  WS 61808016 + 16 [DBWR]
  8,2    1       86    13.706869236  8526  D  WS 61808016 + 16 [DBWR]
  8,2    1       87    13.707369836     0  C  WS 61808016 + 16 [0]
  8,2    1       88    13.707439293  8526  A WSM 59645972 + 2 <- (253,2) 43128852
  8,0    1       89    13.707439750  8526  A WSM 61745172 + 2 <- (8,2) 59645972
  8,2    1       90    13.707440632  8526  Q WSM 61745172 + 2 [DBWR]
  8,2    1       91    13.707444147  8526  G WSM 61745172 + 2 [DBWR]
  8,2    1       92    13.707445046  8526  P   N [DBWR]
  8,2    1       93    13.707446646  8526  I WSM 61745172 + 2 [DBWR]
  8,2    1       94    13.707447986  8526  U   N [DBWR] 1
  8,2    1       95    13.707449109  8526  D WSM 61745172 + 2 [DBWR]
  8,2    1       96    13.709796523     0  C WSM 61745172 + 2 [0]
  8,2    1       97    13.709923402  8526  A  WS 59924376 + 16 <- (253,2) 43407256
  8,0    1       98    13.709923927  8526  A  WS 62023576 + 16 <- (8,2) 59924376
  8,2    1       99    13.709924789  8526  Q  WS 62023576 + 16 [DBWR]
  8,2    1      100    13.709928558  8526  G  WS 62023576 + 16 [DBWR]
  8,2    1      101    13.709930325  8526  I  WS 62023576 + 16 [DBWR]
  8,2    1      102    13.709932253  8526  D  WS 62023576 + 16 [DBWR]
  8,2    1      103    13.710439294     0  C  WS 62023576 + 16 [0]
  8,2    1      104    13.710504154  8526  A WSM 59645974 + 2 <- (253,2) 43128854
  8,0    1      105    13.710504615  8526  A WSM 61745174 + 2 <- (8,2) 59645974
  8,2    1      106    13.710505414  8526  Q WSM 61745174 + 2 [DBWR]
  8,2    1      107    13.710509209  8526  G WSM 61745174 + 2 [DBWR]
  8,2    1      108    13.710509951  8526  P   N [DBWR]
  8,2    1      109    13.710511438  8526  I WSM 61745174 + 2 [DBWR]
  8,2    1      110    13.710512647  8526  U   N [DBWR] 1
  8,2    1      111    13.710513847  8526  D WSM 61745174 + 2 [DBWR]
  8,2    1      112    13.712818943  8561  C WSM 61745174 + 2 [0]
  8,2    1      113    13.712920383  8526  A  WS 64168232 + 16 <- (253,2) 47651112
  8,0    1      114    13.712920831  8526  A  WS 66267432 + 16 <- (8,2) 64168232
  8,2    1      115    13.712921580  8526  Q  WS 66267432 + 16 [DBWR]
  8,2    1      116    13.712924820  8526  G  WS 66267432 + 16 [DBWR]
  8,2    1      117    13.712926391  8526  I  WS 66267432 + 16 [DBWR]
  8,2    1      118    13.712928372  8526  D  WS 66267432 + 16 [DBWR]
  8,2    1      119    13.713235899  8561  C  WS 66267432 + 16 [0]
  8,2    1      120    13.713662401  8526  A WSM 59645976 + 2 <- (253,2) 43128856
  8,0    1      121    13.713662772  8526  A WSM 61745176 + 2 <- (8,2) 59645976
  8,2    1      122    13.713663694  8526  Q WSM 61745176 + 2 [DBWR]
  8,2    1      123    13.713667316  8526  G WSM 61745176 + 2 [DBWR]
  8,2    1      124    13.713668108  8526  P   N [DBWR]
  8,2    1      125    13.713669584  8526  I WSM 61745176 + 2 [DBWR]
  8,2    1      126    13.713670677  8526  U   N [DBWR] 1
  8,2    1      127    13.713672227  8526  D WSM 61745176 + 2 [DBWR]
  8,2    1      128    13.713971679     0  C WSM 61745176 + 2 [0]
  8,2    3        1    30.063403203  8601  A  WS 38092648 + 8 <- (253,2) 21575528
  8,0    3        2    30.063403738  8601  A  WS 40191848 + 8 <- (8,2) 38092648
  8,2    3        3    30.063405432  8601  Q  WS 40191848 + 8 [WORKER]
  ......


  8,2    7       44    40.700779961  8527  P   N [DBWR]
  8,2    7       45    40.700781334  8527  I WSM 61745238 + 2 [DBWR]
  8,2    7       46    40.700782373  8527  U   N [DBWR] 1
  8,2    7       47    40.700783345  8527  D WSM 61745238 + 2 [DBWR]
  8,2    7       48    40.702053025     0  C WSM 61745238 + 2 [0]
  8,2    7       49    40.703384715  8527  A  WS 59826088 + 1024 <- (253,2) 43308968
  8,0    7       50    40.703385130  8527  A  WS 61925288 + 1024 <- (8,2) 59826088
  8,2    7       51    40.703385848  8527  Q  WS 61925288 + 1024 [DBWR]
  8,2    7       52    40.703388681  8527  G  WS 61925288 + 1024 [DBWR]
  8,2    7       53    40.703391836  8527  I  WS 61925288 + 1024 [DBWR]
  8,2    7       54    40.703393673  8527  D  WS 61925288 + 1024 [DBWR]
  8,2    7       55    40.704013939  8527  A  WS 59827112 + 1024 <- (253,2) 43309992
  8,0    7       56    40.704014340  8527  A  WS 61926312 + 1024 <- (8,2) 59827112
  8,2    7       57    40.704014895  8527  Q  WS 61926312 + 1024 [DBWR]
  8,2    7       58    40.704017421  8527  G  WS 61926312 + 1024 [DBWR]
  8,2    7       59    40.704020391  8527  I  WS 61926312 + 1024 [DBWR]
  8,2    7       60    40.704021794  8527  D  WS 61926312 + 1024 [DBWR]
  8,2    7       61    40.704536968  8527  A  WS 59828136 + 544 <- (253,2) 43311016
  8,0    7       62    40.704537493  8527  A  WS 61927336 + 544 <- (8,2) 59828136
  8,2    7       63    40.704538288  8527  Q  WS 61927336 + 544 [DBWR]
  8,2    7       64    40.704541061  8527  G  WS 61927336 + 544 [DBWR]
  8,2    7       65    40.704544014  8527  I  WS 61927336 + 544 [DBWR]
  8,2    7       66    40.704545558  8527  D  WS 61927336 + 544 [DBWR]
  8,2    7       67    40.705417456     0  C  WS 61926312 + 1024 [0]
  8,2    7       68    40.705541425     0  C  WS 61925288 + 1024 [0]
  8,2    7       69    40.706835171     0  C  WS 61927336 + 544 [0]
  。。。。。。
  8,2    7      160    40.721064114  8527  A  WS 64741976 + 16 <- (253,2) 48224856
  8,0    7      161    40.721064569  8527  A  WS 66841176 + 16 <- (8,2) 64741976
  8,2    7      162    40.721065340  8527  Q  WS 66841176 + 16 [DBWR]
  8,2    7      163    40.721068190  8527  G  WS 66841176 + 16 [DBWR]
  8,2    7      164    40.721069466  8527  I  WS 66841176 + 16 [DBWR]
  8,2    7      165    40.721071347  8527  D  WS 66841176 + 16 [DBWR]
  8,2    7      166    40.721268139  8527  A  WS 65612600 + 1024 <- (253,2) 49095480
  8,0    7      167    40.721268650  8527  A  WS 67711800 + 1024 <- (8,2) 65612600
  8,2    7      168    40.721269188  8527  Q  WS 67711800 + 1024 [DBWR]
  8,2    7      169    40.721270982  8527  G  WS 67711800 + 1024 [DBWR]
  8,2    7      170    40.721273632  8527  I  WS 67711800 + 1024 [DBWR]
  8,2    7      171    40.721274724  8527  D  WS 67711800 + 1024 [DBWR]
  8,2    7      172    40.721963819  8527  C  WS 66841176 + 16 [0]
  8,2    7      173    40.722124955  8527  A  WS 65613624 + 1024 <- (253,2) 49096504
  8,0    7      174    40.722125503  8527  A  WS 67712824 + 1024 <- (8,2) 65613624
  8,2    7      175    40.722126448  8527  Q  WS 67712824 + 1024 [DBWR]
  8,2    7      176    40.722129863  8527  G  WS 67712824 + 1024 [DBWR]
  8,2    7      177    40.722134286  8527  I  WS 67712824 + 1024 [DBWR]
  8,2    7      178    40.722136074  8527  D  WS 67712824 + 1024 [DBWR]
  8,2    7      179    40.722864681  8527  A  WS 65614648 + 32 <- (253,2) 49097528
  8,0    7      180    40.722865039  8527  A  WS 67713848 + 32 <- (8,2) 65614648
  8,2    7      181    40.722865720  8527  Q  WS 67713848 + 32 [DBWR]
  8,2    7      182    40.722868126  8527  G  WS 67713848 + 32 [DBWR]
  8,2    7      183    40.722869365  8527  I  WS 67713848 + 32 [DBWR]
  8,2    7      184    40.722870938  8527  D  WS 67713848 + 32 [DBWR]
  8,2    7      185    40.722968313  8527  A  WS 65615160 + 256 <- (253,2) 49098040
  8,0    7      186    40.722968631  8527  A  WS 67714360 + 256 <- (8,2) 65615160
  8,2    7      187    40.722969119  8527  Q  WS 67714360 + 256 [DBWR]
  8,2    7      188    40.722970629  8527  G  WS 67714360 + 256 [DBWR]
  8,2    7      189    40.722972042  8527  I  WS 67714360 + 256 [DBWR]
  8,2    7      190    40.722973008  8527  D  WS 67714360 + 256 [DBWR]
  8,2    7      191    40.724848855     0  C  WS 67714360 + 256 [0]
  8,2    7      192    40.724994181     0  C  WS 67711800 + 1024 [0]
  8,2    7      193    40.726535926     0  C  WS 67713848 + 32 [0]
  8,2    7      194    40.726539508     0  C  WS 67712824 + 1024 [0]
 。。。。。。
  8,2    3      275    40.736419873  8525  A  WS 64168488 + 16 <- (253,2) 47651368
  8,0    3      276    40.736420281  8525  A  WS 66267688 + 16 <- (8,2) 64168488
  8,2    3      277    40.736421120  8525  Q  WS 66267688 + 16 [CKPT]
  8,2    3      278    40.736423906  8525  G  WS 66267688 + 16 [CKPT]
  8,2    3      279    40.736425223  8525  I  WS 66267688 + 16 [CKPT]
  8,2    3      280    40.736426923  8525  D  WS 66267688 + 16 [CKPT]
  8,2    3      281    40.736771857     0  C  WS 66267688 + 16 [0]
  8,2    3      282    40.736813613  8525  A WSM 59646060 + 2 <- (253,2) 43128940
  8,0    3      283    40.736813974  8525  A WSM 61745260 + 2 <- (8,2) 59646060
  8,2    3      284    40.736814499  8525  Q WSM 61745260 + 2 [CKPT]
  8,2    3      285    40.736816724  8525  G WSM 61745260 + 2 [CKPT]
  8,2    3      286    40.736817426  8525  P   N [CKPT]
  8,2    3      287    40.736818608  8525  I WSM 61745260 + 2 [CKPT]
  8,2    3      288    40.736819547  8525  U   N [CKPT] 1
  8,2    3      289    40.736820242  8525  D WSM 61745260 + 2 [CKPT]
  8,2    3      290    40.738214216     0  C WSM 61745260 + 2 [0]
 。。。。。。


Total (sda2):
 Reads Queued:           0,        0KiB  Writes Queued:         134,    5,867KiB
 Read Dispatches:        0,        0KiB  Write Dispatches:      127,    5,869KiB
 Reads Requeued:         0               Writes Requeued:         0
 Reads Completed:        0,        0KiB  Writes Completed:      127,    5,869KiB
 Read Merges:            0,        0KiB  Write Merges:            7,       32KiB
 IO unplugs:            52               Timer unplugs:           0


Throughput (R/W): 0KiB/s  144KiB/s
Events (sda2): 1,021 entries
Skips: 0 forward (0 -   0.0%)

然后通过btt -i sda2.blktrace_all.parse 进一步格式化之后，我们选择其中一个便宜量的位置来看看：

  8,2    7       51    40.703385848  8527  Q  WS 61925288 + 1024 [DBWR]
  8,2    7       52    40.703388681  8527  G  WS 61925288 + 1024 [DBWR]
  8,2    7       53    40.703391836  8527  I  WS 61925288 + 1024 [DBWR]
  8,2    7       54    40.703393673  8527  D  WS 61925288 + 1024 [DBWR]
  8,2    7       55    40.704013939  8527  A  WS 59827112 + 1024 <- (253,2) 43309992
  8,0    7       56    40.704014340  8527  A  WS 61926312 + 1024 <- (8,2) 59827112
  8,2    7       57    40.704014895  8527  Q  WS 61926312 + 1024 [DBWR]
  8,2    7       58    40.704017421  8527  G  WS 61926312 + 1024 [DBWR]
  8,2    7       59    40.704020391  8527  I  WS 61926312 + 1024 [DBWR]
  8,2    7       60    40.704021794  8527  D  WS 61926312 + 1024 [DBWR]
  8,2    7       61    40.704536968  8527  A  WS 59828136 + 544 <- (253,2) 43311016
  8,0    7       62    40.704537493  8527  A  WS 61927336 + 544 <- (8,2) 59828136
  8,2    7       63    40.704538288  8527  Q  WS 61927336 + 544 [DBWR]
  8,2    7       64    40.704541061  8527  G  WS 61927336 + 544 [DBWR]
  8,2    7       65    40.704544014  8527  I  WS 61927336 + 544 [DBWR]
  8,2    7       66    40.704545558  8527  D  WS 61927336 + 544 [DBWR]
  8,2    7       67    40.705417456     0  C  WS 61926312 + 1024 [0]
  8,2    7       68    40.705541425     0  C  WS 61925288 + 1024 [0]

这里我们过滤其中的偏移量 61925288,则可以看到该IO操作的前后位置：

[root@yashandb1 ~]# cat sda2.blktrace_all.parse.offset_8,2_w.dat|grep 61925288
   40.703393673 61925288 61926312
[root@yashandb1 ~]# cat sda2.blktrace_all.parse.offset_8,2_c.dat|grep 61925288
   40.703393673 61925288 61926312
[root@yashandb1 ~]#

根据前后数据相减，可以发现刚好等于1024，跟最前面看到的偏移量是、所读的block数是一致的。需要注意的是，这里的block是OS block。简单的讲，这一个DBWR的IO写请求，在os层实际上调用了1024次，大概也就是512kb。

同时在进行测试的过程中，还发现了一些有趣的地方；比如表被truncate后，对象的data_object_id会加1，这与Oracle的机制一致，如下：

SQL>  select object_id,data_object_id from dba_objects where object_name='TEST1';


            OBJECT_ID        DATA_OBJECT_ID 
--------------------- --------------------- 
                 2288                  2289


1 row fetched.
SQL>

其次还发现崖山数据库也存在ROWID的概念，虽然看上去跟Oracle ROWID不太一样，但是表达的含义确是一致的，甚至看起来我认为更直观，从这里可以看出，设计者是动过一些思考的。

SQL> select rowid from test1 where rownum < 3;


ROWID                                        
-------------------------------------------- 
2289:4:0:21652:0                            
2289:4:0:21652:1                            


2 rows fetched.


SQL> select * from test1 where rowid='2289:4:0:21652:0';


OWNER        OBJECT_NAME            SUBOBJECT_NAME                  OBJECT_ID        DATA_OBJECT_ID OBJECT_TYPE           CREATED      LAST_DDL_TIME     TIMESTAMP STATUS    TEMPORARY GENERATED SECONDARY    NAMESPACE SHARING EDITIONABLE DATABASE_MAINTAINED APPLICATION DUPLICATED SHARDED 
------------ ---------------------- ------------------- --------------------- --------------------- --------------------- ------------ ----------------- --------- --------- --------- --------- --------- ------------ ------- ----------- ------------------- ----------- ---------- ------- 
ENMO         TEST115                                                     2272                  2272 TABLE                 2023-11-15   2023-11-15                  VALID     N                                        1 NONE                N                               N          N      


1 row fetched.
SQL>

不难看出崖山数据库的ROWID结构为：data_object_id:tbs_id:file_id:block_number:row#.

最后简单总结一下：

1、崖山数据库支持多块写，支持IO合并；单次最大IO应该是1mb。

2、支持rowid,且结构与Oracle一致，更加直观。

至于其他的一些功能特性，有时间再研究。

yashandb yashandb体验官

最后修改时间：2023-11-23 15:22:46

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