I don't how OSPG can be a considerably different size. Small variations
happen but this does not look small.
Lorenz's advice to run a compaction and see what the indexes sizes are
is a good idea. A backup would also be a good idea because something is
unexpected (backup uses GSPO).
There has been some fixes in compaction since 4.4.0 related to
compacting while also active in Fuseki.
This index does not store the literals strings representations - they
are referenced via the 8 byte entries. In OSPG, the index entries are 4
slots of 8 bytes.
Andy
(Unrelated comment below)
On 28/01/2023 07:47, Lorenz Buehmann wrote:
Hi Elton,
Do you have lots of may large literals in your data?
Also, did you try a compaction on the database? If not, can you try it
and post the new file sizes afterwards? Note, they will be located in a
new ./Data-XXXX directory, e.g. before Data-0001 and afterwards Data-0002
By the way, we're now at Jena 4.7.0 - you might have a look at release
notes of the last 3 versions, maybe things you have recognized while
running you current Fuseki. If not, just keep it running if you're happy
with it of course.
Theer
Cheers,
Lorenz
On 28.01.23 03:10, Elton Soares wrote:
Dear Jena Community,
I'm running Jena Fuseki Version 4.4.0 as a container on an OpenShift
Cluster.
OS Version Info (cat /etc/os-release):
NAME="Red Hat Enterprise Linux"
VERSION="8.5 (Ootpa)"
ID="rhel"
ID_LIKE="fedora" ="8.5"
...
Hardware Info (from Jena Fuseki initialization log):
[2023-01-27 20:08:59] Server INFO Memory: 32.0 GiB
[2023-01-27 20:08:59] Server INFO Java: 11.0.14.1
[2023-01-27 20:08:59] Server INFO OS: Linux
3.10.0-1160.76.1.el7.x86_64 amd64
[2023-01-27 20:08:59] Server INFO PID: 1
Disk Info (df -h):
Filesystem
Size Used Avail Use% Mounted on
overlay
99G 76G 18G 82% /
tmpfs
64M 0 64M 0% /dev
tmpfs
63G 0 63G 0% /sys/fs/cgroup
shm
64M 0 64M 0% /dev/shm
/dev/mapper/docker_data
99G 76G 18G 82% /config
/data
1.0T 677G 348G 67% /usr/app/run
tmpfs
40G 24K 40G 1%
My dataset is built using TDB2, and currently has the following RDF
Stats:
· Triples: 65KK (Approximately 65 million)
· Subjects: ~20KK (Aproximately 20 million)
· Objects: ~8KK (Aproximately 8 million)
· Graphs: ~213K (Aproximately 213 thousand)
· Predicates: 153
The files corresponding to this dataset alone on disk sum up to
approximately 671GB (measured with du -h). From these, the largest
files are:
· /usr/app/run/databases/my-dataset/Data-0001/OSPG.dat: 243GB
· /usr/app/run/databases/my-dataset/Data-0001/nodes.dat: 76GB
· /usr/app/run/databases/my-dataset/Data-0001/POSG.dat: 35GB
· /usr/app/run/databases/my-dataset/Data-0001/nodes.idn: 33GB
· /usr/app/run/databases/my-dataset/Data-0001/POSG.idn: 29GB
· /usr/app/run/databases/my-dataset/Data-0001/OSPG.idn: 27GB
I've looked into several documentation pages, source code, forums, ...
nowhere I was able to find some explanation to why OSPG.dat is so much
larger than all other files.
I've been using Jena for quite some time now and I'm well aware that
its indexes grow significantly during usage, specially when triples
are being added across multiple requests (transactional workloads).
Even though, the size of this particular file (OSPG.dat) surprised me,
as in my prior experience the indexes would never get larger than the
nodes.dat file.
Is there a reasonable explanation for this based on the content of the
dataset or the way it was generated? Could this be an indexing bug
within TDB2?
Thank you for your support!
For completeness, here is the assembler configuration for my dataset:
@prefix : http://base/# .
@prefix fuseki: http://jena.apache.org/fuseki# .
@prefix ja: http://jena.hpl.hp.com/2005/11/Assembler# .
@prefix rdf: http://www.w3.org/1999/02/22-rdf-syntax-ns# .
@prefix rdfs: http://www.w3.org/2000/01/rdf-schema# .
@prefix root: http://dev-test-jena-fuseki/$/datasets .
@prefix tdb2: http://jena.apache.org/2016/tdb# .
It only needs:
:service_tdb_my-dataset
rdf:type fuseki:Service ;
rdfs:label "TDB my-dataset" ;
fuseki:dataset :ds_my-dataset ;
fuseki:name "my-dataset" ;
fuseki:serviceQuery "sparql" , "query" ;
fuseki:serviceReadGraphStore "get" ;
fuseki:serviceReadWriteGraphStore
"data" ;
fuseki:serviceUpdate "update" ;
fuseki:serviceUpload "upload" .
:ds_my-dataset rdf:type tdb2:DatasetTDB2 ;
tdb2:location "run/databases/my-dataset" ;
tdb2:unionDefaultGraph true ;
ja:context \[ ja:cxtName "arq:optFilterPlacement" ;
ja:cxtValue "false"
\] .
The rest can go.
This issue has been also published at
https://stackoverflow.com/questions/75264889/why-does-the-ospg-dat-file-grows-so-much-more-than-all-other-files
