Bugs item #1654317, was opened at 2007-02-07 17:23
Message generated for change (Comment added) made by stmane
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Category: PF/runtime
Group: Pathfinder CVS Head
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Jan Rittinger (tsheyar)
Assigned to: Nobody/Anonymous (nobody)
Summary: XQ: following step kills Mserver (after 2h)
Initial Comment:
Running the attached query on a MBench generated XML file (sf=0.1,
name=mbench0.1.xml) kills the Mserver after a long, long time with a
Segmentation fault. (Using -d10 doesn't change a thing.)
The reason either is the missing loop-lifting of the following step or the very
large intermediate result (#ctx=2093, #nodes_in_doc=203089).
Afterwards the database BACKUP is broken:
!ERROR: force_move: link(bat/BACKUP/542.desc,bat05/542.desc)=-1
!OS: No such file or directory
!ERROR: force_move: link(bat/BACKUP/544.desc,bat05/544.desc)=-1
!OS: No such file or directory
!ERROR: force_move: link(bat/BACKUP/603.desc,bat06/603.desc)=-1
!OS: No such file or directory
!ERROR: force_move: link(bat/BACKUP/553.desc,bat05/553.desc)=-1
!OS: No such file or directory
!ERROR: force_move: link(bat/BACKUP/554.desc,bat05/554.desc)=-1
!OS: No such file or directory
!ERROR: force_move: link(bat/BACKUP/570.desc,bat05/570.desc)=-1
!OS: No such file or directory
!ERROR: BBPrecover: recovery failed. Please check whether your disk is full or
write-protected.
!FATAL: BBPinit: cannot properly process bat/BACKUP.
Removing folder BACKUP helps.
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>Comment By: Stefan Manegold (stmane)
Date: 2007-05-12 19:10
Message:
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user_id=572415
Originator: NO
On a 2 GHz Opteron with 8 GB RAM,
the query seems to "work":
compiled with optimization enabled and using 32-bit OIDs
Mserver grows up to 8 GB, finishes after ~30 min (ALG) resp.
~2 h (MPS) (both CPU bound) without error, and produces some
result (identical for MPS & ALG) --- did not check by hand,
though, whether the result is correct or not.
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Comment By: Jan Rittinger (tsheyar)
Date: 2007-02-07 18:03
Message:
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user_id=993208
Originator: YES
No to your first question. It basically is the following query (compiled
with the algebra version):
doc("mbench0.1.xml")//[EMAIL PROTECTED]/(let $child := ./child::*[1] return
if (exists($child)) then $child else ./following::*[1])
(Based form the starting set apply the following step for all nodes that
have no child (#ctx=2093) and throw away everything except the first one.)
The whole thing took quite a while (~2 hours) and was always I/O bound.
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Comment By: Stefan Manegold (stmane)
Date: 2007-02-07 17:42
Message:
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Is the query one of the standard MBench queries?
If so, which one?
The "milprint_summer" version is known to have problems with MBench
queries qa04, qj01, qj02, qj03, qj04; cf.,
http://monetdb.cvs.sourceforge.net/monetdb/pathfinder/benchmarks/MBench/Tests/All?view=log#rev1.2
http://monetdb.cvs.sourceforge.net/*checkout*/monetdb/pathfinder/benchmarks/MBench/Tests/All
Of course, Mserver should not segfault, but (at most) "fail properly"...
Did you check/watch how big does your Mserver grows (grew) before
crashing?
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