[Box Backup-commit] Re: #7: Improve restore speed on local repositories

[boxbackup-dev@fluffy.co.uk]

#7: Improve restore speed on local repositories
----------------------------+-----------------------------------------------
  Reporter:  martin         |       Owner:      
      Type:  task           |      Status:  new 
  Priority:  minor          |   Milestone:  0.20
 Component:  box libraries  |     Version:  0.10
Resolution:                 |    Keywords:      
----------------------------+-----------------------------------------------
Comment (by chris):

 I think there is another problem here: bbstored is quite inefficient in
 how it handles directories. During a compare, it spends most of its time
 reading directories:

 stat64("/mnt/tmp/boxbackup/backup/00000002/54/0e/o8a.rfw",
 {st_mode=S_IFREG|0664, st_size=497, ...}) = 0
 open("/mnt/tmp/boxbackup/backup/00000002/54/0e/o8a.rfw",
 O_RDONLY|O_LARGEFILE) = 6
 fstat64(6, {st_mode=S_IFREG|0664, st_size=497, ...}) = 0
 read(6, "DIR_\0\0\0\6\0\0\0\0\0\16T\212\0\0\0\0\0\16Tp\0\3\357b"..., 36) =
 36
 read(6, "\0\0\0001", 4)                 = 4
 read(6, "\2WN\10\377\231\205\264\33\331\362\266\214\22\16+h\326"..., 49) =
 49
 read(6, "\0\3\3278\366&\244\200\0\0\0\0\0\16T\213\0\0\0\0\0\0\0"..., 34) =
 34
 read(6, "\212\0", 2)                    = 2
 read(6, "\340zWk\204\35\371\327\277\247\356\353\346`k\346\32\324"..., 32)
 = 32
 read(6, "\0\0\0\0", 4)                  = 4
 read(6, "\0\3\3278\366&\244\200\0\0\0\0\0\16T\214\0\0\0\0\0\0\0"..., 34) =
 34
 read(6, "\212\0", 2)                    = 2
 read(6, "\2259o\253X\246P\242\263\4\27\310\243\2171\331\340b\222"..., 32)
 = 32
 read(6, "\0\0\0\0", 4)                  = 4
 read(6, "\0\3\3278\366&\244\200\0\0\0\0\0\16T\215\0\0\0\0\0\0\0"..., 34) =
 34
 read(6, "j\0", 2)                       = 2
 read(6, "\311N\320a$\345\337\313\231F\207I\253X\310;W\5\335\10v"..., 24) =
 24
 read(6, "\0\0\0\0", 4)                  = 4
 read(6, "\0\3\3278\366&\244\200\0\0\0\0\0\16T\216\0\0\0\0\0\0\0"..., 34) =
 34
 read(6, "\212\0", 2)                    = 2
 read(6, "\320\tHOM\'\232\266\27U\322U\203\323L\227\336\252\263P"..., 32) =
 32
 read(6, "\0\0\0\0", 4)                  = 4
 read(6, "\0\3\3278\366&\244\200\0\0\0\0\0\16T\217\0\0\0\0\0\0\0"..., 34) =
 34
 read(6, "\212\0", 2)                    = 2
 read(6, "|\225\224\'\f\273\tr\376\255\321\325:7\356{e\23x\317gs"..., 32) =
 32
 read(6, "\0\0\0\0", 4)                  = 4
 read(6, "\0\3\331\304q\22\262\0\0\0\0\0\0\16T\220\0\0\0\0\0\0\0"..., 34) =
 34
 read(6, "J\0", 2)                       = 2
 read(6, "\\\3405\214\367\317>+#\235\350\351\203\356\325\360", 16) = 16
 read(6, "\0\0\0\0", 4)                  = 4
 close(6)

 Reading 34 bytes at a time is just no fun. I think we should have a
 caching reader (like a BufferedReader in Java) that reads 4k blocks each
 time.

-- 
Ticket URL: <http://bbdev.fluffy.co.uk/trac/ticket/7#comment:2>
Box Backup <http://www.fluffy.co.uk/boxbackup/>
An open source, completely automatic on-line backup system for UNIX.