Hi Andy, With kind support by a IT infrastructures colleague, I'll temporarily have 32 GB mem for the next run.
Are you aware of any possibility to check how much of the OS managed memory is used for TDB? I just wonder how much would be enough ... Cheers, Joachim -----Ursprüngliche Nachricht----- Von: Andy Seaborne [mailto:[email protected]] Gesendet: Samstag, 2. November 2013 13:40 An: [email protected] Betreff: Re: AW: Declining TDB load performance with larger files On 01/11/13 12:42, Neubert Joachim wrote: > I did a comparison of tdbloader vs. tdbloader2. The results are not relieable > (machine-dependent, and perhaps even influenced by different background load > on the vm cluster), but perhaps even then they may be interesting to others: > Thanks - I'm interested - and if anyone has examples that would be useful information as well. Which OS is this? And specifically, does sort(1) have the --parallel options? (Ubuntu does; centos does not at the moment). > tdbloader w/ 2G heap > 4:15 Data phase > 4:30 Index phase > > tdbloader2 w/ 2G heap > 1:30 Data phase > 6:30 Index phase > > So in sum tdbloader2 shows a slight advantage in my current configuration. This is what I've been finding when the laod is a bit more than the machine has RAM for it's current working set. The sortign in the index phase of tdblaoder2 sometimes, on some systems, takes much longer than I think it should. I even had an example last week when making the sort(1) space less speeded it up which I find bizarre. > The reduction of heap space had indeed brought an improvement: > > tdbloader w/ 10G heap > 4:30 Data phase > 5:45 Index phase > > Could I expect a larger improvement by adding more memory (for example > upgrading from 11 to 32 GB)? Are there any experiences for estimating an > optimal memory size for tdb loading? Most likely. The loading rate is susceptible to system issues as we've all been finding, and at the moment, I don't have a good model for wwhat teh factors are. But for a given setup, more RAM is good especially for the all java tdbloader. Andy > > Cheers, Joachim > > -----Ursprüngliche Nachricht----- > Von: Andy Seaborne [mailto:[email protected]] > Gesendet: Montag, 28. Oktober 2013 16:58 > An: [email protected] > Betreff: Re: Declining TDB load performance with larger files > > Hi Joachim, > > What is happing is that the system is running out of working space and the > disk is being used for real. > > > JAVA_OPTS: -d64 -Xms6g -Xmx10g > > Don't set -Xmx10g. Try a 2G heap. Don't bother with -Xms. > > More heap does not help - in fact, it can make it worse. TDB uses memory > mapped files - these are not in Java heap space. The operating system > manages how much real RAM is devoted to the virtual address space for the > file. As your JVM grows, it is reducing the space for file caching. > > > There is another effect. The OS is managing memory but sometimes it > gets its policy wrong. Oddly, the faster the initial part of the load, > the slower the speed drops off to when workspace RAM runs out. My guess is > that the OS guesses some acecss style and then code then breaks that > assumption. It can even different from run to run on the same machine. > > There is also tdbloader2 - it may be faster, it may not. It is vulnerable to > OS in different ways. > > As it is so per-system specific, try each and see what happens, after fixing > the heap issue. > > Andy > > > On 28/10/13 12:01, Neubert Joachim wrote: >> I'm loading a 111 million triples file (GND German Authority files). >> For the first roughly 70 million triples, it's really fast (more than >> 60,000 avg), but then throughput declines continuously to a thousand >> or just some hundred triples (which brings down the avg to less than >> 7000). During the last part of triples data phase, java is down to >> 1-2% CPU usage, while disk usage goes up to 100%. >> >> As TDB writes to disk, I'd expect rather linear loading times. The >> Centos 6 64bit machine (11.5 GB memory) runs on a VMware vSphere >> cluster, with SAN hardware under-laying. As I observed the same >> behavior at different times a day, with for sure different load >> situations, there is no indication that it depended on parallel >> actions on the cluster. >> >> Perhaps there is something wrong in my config, but I could not figure >> out what it may be. I add an extract of the log below - it would be >> great if somebody could help me with hints. >> >> Cheers, Joachim >> > > > --------------- > > > > 2013-10-25 13:33:33 start run > > > > Configuration: > > java version "1.6.0_24" > > Java(TM) SE Runtime Environment (build 1.6.0_24-b07) > Java HotSpot(TM) > 64-Bit Server VM (build 19.1-b02, mixed mode) > JAVA_OPTS: -d64 -Xms6g > -Xmx10g > > Jena: VERSION: 2.11.0 > > Jena: BUILD_DATE: 2013-09-12T10:49:49+0100 > > ARQ: VERSION: 2.11.0 > > ARQ: BUILD_DATE: 2013-09-12T10:49:49+0100 > > RIOT: VERSION: 2.11.0 > > RIOT: BUILD_DATE: 2013-09-12T10:49:49+0100 > > TDB: VERSION: 1.0.0 > > TDB: BUILD_DATE: 2013-09-12T10:49:49+0100 > > > > Use fuseki tdb.tdbloader on file /opt/thes/var/gnd/latest/src/GND.ttl.gz > > INFO -- Start triples data phase > > INFO ** Load empty triples table > > INFO Load: /opt/thes/var/gnd/latest/src/GND.ttl.gz -- 2013/10/25 > 13:33:35 MESZ > > INFO Add: 10.000.000 triples (Batch: 64.766 / Avg: 59.984) > > INFO Elapsed: 166,71 seconds [2013/10/25 13:36:21 MESZ] > > INFO Add: 20.000.000 triples (Batch: 71.839 / Avg: 58.653) > > INFO Elapsed: 340,99 seconds [2013/10/25 13:39:16 MESZ] > > INFO Add: 30.000.000 triples (Batch: 67.750 / Avg: 60.271) > > INFO Elapsed: 497,75 seconds [2013/10/25 13:41:52 MESZ] > > INFO Add: 40.000.000 triples (Batch: 68.212 / Avg: 60.422) > > INFO Elapsed: 662,01 seconds [2013/10/25 13:44:37 MESZ] > > INFO Add: 50.000.000 triples (Batch: 54.171 / Avg: 60.645) > > INFO Elapsed: 824,47 seconds [2013/10/25 13:47:19 MESZ] > > INFO Add: 60.000.000 triples (Batch: 58.823 / Avg: 60.569) > > INFO Elapsed: 990,60 seconds [2013/10/25 13:50:05 MESZ] > > INFO Add: 70.000.000 triples (Batch: 45.495 / Avg: 60.468) > > INFO Elapsed: 1.157,63 seconds [2013/10/25 13:52:52 MESZ] > > INFO Add: 80.000.000 triples (Batch: 50.050 / Avg: 57.998) > > INFO Elapsed: 1.379,36 seconds [2013/10/25 13:56:34 MESZ] > > INFO Add: 90.000.000 triples (Batch: 13.954 / Avg: 52.447) > > INFO Elapsed: 1.716,02 seconds [2013/10/25 14:02:11 MESZ] > > INFO Add: 100.000.000 triples (Batch: 1.134 / Avg: 19.024) > > INFO Elapsed: 5.256,29 seconds [2013/10/25 15:01:11 MESZ] > > INFO Add: 110.000.000 triples (Batch: 944 / Avg: 7.643) > > INFO Elapsed: 15.942,27 seconds [2013/10/25 17:59:17 MESZ] > > INFO -- Finish triples data phase > > INFO 111.813.447 triples loaded in 16.288,16 seconds [Rate: 6.864,71 per > second] > > Indexing phase also takes its time, and has some decrease in > performance too, but does not show a sharp drop. > > > > INFO -- Start triples index phase > > INFO Elapsed: 20.563,36 seconds [2013/10/25 19:16:18 MESZ] > > INFO ** Index SPO->POS: 111.786.233 slots indexed in 4.371,67 seconds > [Rate: 25.570,57 per second] > ... > > INFO -- Finish triples index phase > > INFO ** 111.786.233 triples indexed in 19.973,81 seconds [Rate: > 5.596,64 per second] > > INFO -- Finish triples load > > INFO ** Completed: 111.813.447 triples loaded in 36.261,98 > seconds > [Rate: 3.083,49 per second] > > > > >
