RE: svn client fails with Berkeley DB error Cannot allocate memor y - repository wedges

On 01-Jun-2004 Alblas Huibert wrote:
> Hi,
>
> If you call your script recursivly,
> it could end up having _many_ "open connections"....

Agreed but the recursion depth only ever gets to 9 (thats not much). The actual
new SVN::Client is only done once and one ls in the recursive function.

> Locks cannot be released until the scripts ends,
> and the script only ends when a subprocess is done.
> I can imagine that 4000 is a limmit way to small on
> a medium sized repository.

Fair enough but at most I would expect a read lock per ls and I don't see why
that cannot be released when the ls completes. Since the depth of recursion I
get to is only 9 I don't have any more than 9 ls's going at once.

> The way you describe your sript it should release
> the subversion server after each "svn ls",
> but maybe something is wrong here.

This is what I suspect. It may be an issue in SVN::Client or in the subversion
libraries.

This worries me alot. We have spent a great deal of effort moving to subversion
and I can "destroy" the repository extremely easily. After running this script
once or twice on a local URL svn recover simply fails with:

sh-2.05$ svnadmin recover linux-x86/
Please wait; recovering the repository may take some time...
svn: DB_RUNRECOVERY: Fatal error, run database recovery

and running the script again gives:

[file:///var/subversion/distribution/linux-x86]
Couldn't open a repository: Unable to open an ra_local session to URL: Unable
to open repository 'file:///var/subversion/distribution/linux-x86': Berkeley DB
error while opening 'nodes' table for filesystem
/var/subversion/distribution/linux-x86/db:
Cannot allocate memory at /tmp/x.pl line 11
sh-2.05$

immediately - that is on the first ls. Each run of svnadmin recover allow the
script to run again up to the usual failure point.

> Exausting your resources is very simple using recursion :-)
>
> Maybe you should rewrite your script to first create
> an infomation file about which parts of the tree to access.
> Then rocess this info afterwards,
> thus separating information gathering, and information processing.

Yes we could do that. The script itself is not that important to us - we can
run it using an http URL and drop the apache max clients to 50 and it runs
slower but works. My concern is not making the script work but that something
is seriously going wrong with our repository. I'm not saying someone would
maliciously run this script to our subversion server but if they did it takes
the repository down and (currently) we've found no way to recover it. We do
want to use SVN::Client quite extensively.

At present our repository is broken. This is not the end of the world as I was
using a test repository (thank god).

> Huibert Alblas
>
> --
> To undestand recursion,
> we must first understand recursion
>
>

Martin

--
Martin J. Evans
Easysoft Ltd, UK
Development
> -----Ursprüngliche Nachricht-----
> Von: Martin J. Evans [mailto:martin.evans@easysoft.com] 
> Gesendet: Dienstag, 1. Juni 2004 10:10
> An: users@subversion.tigris.org
> Cc: sussman@collab.net
> Betreff: Re: svn client fails with Berkeley DB error Cannot allocate memory
> - repository wedges
> 
> 
> Ben,
> 
> On 31-May-2004 Ben Collins-Sussman wrote:
>> On Fri, 2004-05-28 at 06:06, Martin J. Evans wrote:
>>>  Berkeley DB error while opening 'transactions' table for filesys tem 
>>> /var/subversion/distribution/linux-x86/db:
>>> Cannot allocate memory
>> 
>> IIRC, this error often means that BDB has run out of lock objects.  
>> Try increasing the the number of locks in your repos/db/DB_CONFIG file 
>> and then run 'svnadmin recover'.
> 
> Thanks for that. I take you are referring to:
> 
> set_lk_max_locks   2000
> set_lk_max_lockers 2000
> set_lk_max_objects 2000
> 
> Bumping all of these to 4000 did not help. When using file URL:
> 
> Couldn't open a repository: Unable to open an ra_local session to URL:
> Unable to open repository
> 'file:///var/subversion/distribution/linux-x86/common/libraries/extras/tags'
>:
> Berkeley DB error while opening 'uuids' table for filesystem
> /var/subversion/distribution/linux-x86/db:
> Cannot allocate memory at /tmp/x.pl line 11
> 
> line 11 is an SVN::Client ls call.
> 
> Once I've run the script:
> 
> sh-2.05$ svnadmin recover linux-x86 
> Please wait; recovering the repository may take some time...
> svn: DB_RUNRECOVERY: Fatal error, run database recovery
> 
> The last lines of strace show (I don't see the reason for the carp):
> 
> stat64("/var/subversion/distribution/linux-x86/db/nodes",
> {st_mode=S_IFREG|0644, st_size=86016, ...}) = 0
> stat64("/var/subversion/distribution/linux-x86/db/nodes",
> {st_mode=S_IFREG|0644, st_size=86016, ...}) = 0
> open("/var/subversion/distribution/linux-x86/db/nodes", O_RDWR|O_LARGEFILE)
> = 4
> fcntl64(4, F_SETFD, FD_CLOEXEC)         = 0
> read(4, "\6\0\0\0$\364\0\0\0\0\0\0b1\5\0\t\0\0\0\0\20\0\0\0\t\0"..., 512) =
> 512
> close(4)                                = 0
> stat64("/var/subversion/distribution/linux-x86/db/nodes",
> {st_mode=S_IFREG|0644, st_size=86016, ...}) = 0
> open("/var/subversion/distribution/linux-x86/db/nodes", O_RDWR|O_LARGEFILE)
> = 4
> fcntl64(4, F_SETFD, FD_CLOEXEC)         = 0
> fstat64(4, {st_mode=S_IFREG|0644, st_size=86016, ...}) = 0
> brk(0x8354000)                          = 0x8354000
> munmap(0x40640000, 16384)               = 0
> munmap(0x4048a000, 327680)              = 0
> munmap(0x404da000, 1466368)             = 0
> close(4)                                = 0
> munmap(0x40448000, 270336)              = 0
> munmap(0x40018000, 8192)                = 0
> stat64("/usr/local/lib/perl5/5.8.2/i686-linux/Carp/Heavy.pmc", 0xbfffef5c) =
> -1 ENOENT (No such file or directory)
> open("/usr/local/lib/perl5/5.8.2/i686-linux/Carp/Heavy.pm",
> O_RDONLY|O_LARGEFILE) = -1 ENOENT (No such file or directory)
> stat64("/usr/local/lib/perl5/5.8.2/Carp/Heavy.pmc", 0xbfffef5c) = -1 ENOENT
> (No such file or directory) open("/usr/local/lib/perl5/5.8.2/Carp/Heavy.pm",
> O_RDONLY|O_LARGEFILE) = 4
> brk(0x8355000)                          = 0x8355000
> fstat64(4, {st_mode=S_IFREG|0444, st_size=5918, ...}) = 0 old_mmap(NULL,
> 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40018000
> read(4, "# Carp::Heavy uses some variable"..., 4096) = 4096
> brk(0x8357000)                          = 0x8357000
> brk(0x8358000)                          = 0x8358000
> brk(0x8359000)                          = 0x8359000
> brk(0x835a000)                          = 0x835a000
> brk(0x835b000)                          = 0x835b000
> brk(0x835c000)                          = 0x835c000
> brk(0x835d000)                          = 0x835d000
> brk(0x835e000)                          = 0x835e000
> brk(0x835f000)                          = 0x835f000
> brk(0x8360000)                          = 0x8360000
> brk(0x8361000)                          = 0x8361000
> brk(0x8362000)                          = 0x8362000
> read(4, ";\n    my $caller = caller($i);\n "..., 4096) = 1822
> brk(0x8363000)                          = 0x8363000
> brk(0x8364000)                          = 0x8364000
> brk(0x8365000)                          = 0x8365000
> brk(0x8366000)                          = 0x8366000
> read(4, "", 4096)                       = 0
> close(4)                                = 0
> munmap(0x40018000, 4096)                = 0
> write(2, "Couldn\'t open a repository: Unab"..., 294) = 294 fcntl64(3,
> F_SETLKW, {type=F_UNLCK, whence=SEEK_SET, start=0, len=0}) = 0
> close(3)                                = 0
> munmap(0x40017000, 4096)                = 0
> _exit(255)                              = ?
> 
> 
>> I'd like to know what your script is doing (or what Web::SVN is doing) 
>> that is so lock-intensive...
> 
> The script simply does an ls on the repository then walks down the
> files/dirs recursively calling itself on dirs. However, for each file/dir it
> gets svn:externals to see if any are defined. The idea was to produce a tree
> of the repository because the repository has a large number of svn:externals
> references. I can mail you seperately with the tree output which would give
> you an idea of the repository structure. The script was in my last email.
> 
> BTW, all that is required is running the script - there is no one else
> accessing the repository.
> 
> Let me know if these is any further info that could help.
> 
> Martin
> --
> Martin J. Evans
> Easysoft Ltd, UK
> Development
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