Performance Benchmark Report ============================ The purpose of this document is to provide very broad performance measurements and comparison between Lakesuperior and Fedora/Modeshape implementations. Lakesuperior v1.0a17 and v1.0a18 were taken into consideration. This is because of the extensive reworking of the whole architecture and complete rewrite of the storage layer, that led to significant performance gains. Environment ----------- Hardware ~~~~~~~~ ‘Rather Snappy’ Laptop ^^^^^^^^^^^^^^^^^^^^^^ - Dell Latitude 7490 Laptop - 8x Intel(R) Core(TM) i7-8650U CPU @ 1.90GHz - 16Gb RAM - SSD - Arch Linux OS - glibc 2.26-11 - python 3.7.0 - lmdb 0.9.22 The laptop was left alone during the process, but some major applications (browser, email client, etc.) were left open. ‘Ole Workhorse’ server ^^^^^^^^^^^^^^^^^^^^^^ - 8x Intel(R) Xeon(R) CPU X5550 @ 2.67GHz - 16Gb RAM - Magnetic drive, XXX RPM Benchmark script ~~~~~~~~~~~~~~~~ `Generator script <../../util/benchmark.py>`__ The script was run with default values: resprectively 10,000 and 100,000 children under the same parent. PUT and POST requests were tested separately. The script calculates only the timings used for the PUT or POST requests, not counting the time used to generate the graphs. Data Set ~~~~~~~~ Synthetic graph created by the benchmark script. The graph is unique for each request and consists of 200 triples which are partly random data, with a consistent size and variation: - 50 triples have an object that is a URI of an external resource (50 unique predicates; 5 unique objects). - 50 triples have an object that is a URI of a repository-managed resource (50 unique predicates; 5 unique objects). - 100 triples have an object that is a 64-character random Unicode string (50 unique predicates; 100 unique objects). LDP Data Retrieval ~~~~~~~~~~~~~~~~~~ REST API request:: time curl http://localhost:8000/ldp/pomegranate > /dev/null SPARQL Query ~~~~~~~~~~~~ *Note:* The query may take a long time and therefore is made on the single-threaded server (``lsup-server``) that does not impose a timeout (of course, gunicorn could also be used by changing the configuration to allow a long timeout). Sample query:: PREFIX ldp: SELECT (COUNT(?s) AS ?c) WHERE { ?s a ldp:Resource . ?s a ldp:Container . } Raw request:: time curl -iXPOST -H'Accept:application/sparql-results+json' \ -H'Content-Type:application/x-www-form-urlencoded; charset=UTF-8' \ -d 'query=PREFIX+ldp:+ SELECT+(COUNT(?s)+AS+?c)'\ '+WHERE+{ ++?s+a+ldp:Resource+. ++?s+a+ldp:Container+. }+' \ http://localhost:5000/query/sparql Python API Retrieval ~~~~~~~~~~~~~~~~~~~~ In order to illustrate the advantages of the Python API, a sample retrieval of the container resource after the load has been timed. This was done in an IPython console:: In [1]: from lakesuperior import env_setup In [2]: from lakesuperior.api import resource as rsrc_api In [3]: %timeit x = rsrc_api.get('/pomegranate').imr Results ------- .. _rather-snappy-laptop-1: ‘Rather Snappy’ Laptop ~~~~~~~~~~~~~~~~~~~~~~ 10K Resources ^^^^^^^^^^^^^ ========================= ============ ============ ============ ============ ================ System PUT Store GET SPARQL Query Py-API retrieval ========================= ============ ============ ============ ============ ================ FCREPO / Modeshape 4.7.5 49ms (100%) 3.7Gb (100%) 6.2s (100%) N/A N/A Lakesuperior 1.0a17 78ms (159%) 298Mb (8%) 2.8s 0m1.194s Not measured Lakesuperior 1.0a18 62ms (126%) 789Mb (21%) 2.2s 0m2.214s 66ms ========================= ============ ============ ============ ============ ================ **Notes:** - The Python API time for the GET request in alpha18 is 8.5% of the request. This means that over 91% of the time is spent serializing the results. This time could be dramatically reduced by using faster serialization libraries, or can be outright zeroed out by an application that uses the Python API directly and manipulates the native RDFLib objects (of course, if a serialized output is eventually needed, that cost is unavoidable). - Similarly, the ``triples`` retrieval method of the SPARQL query only takes 13.6% of the request time. The rest is spent evaluating SPARQL and results. An application can use ``triples`` directly for relatively simple lookups without that overhead. 100K Resources ^^^^^^^^^^^^^^ ========================= =============== ============= ============= =============== ============ ================ System PUT POST Store GET Query Py-API retrieval ========================= =============== ============= ============= =============== ============ ================ FCREPO / Modeshape 4.7.5 500ms* (100%) 38ms (100%) 13Gb (100%) 2m6.7s (100%) N/A N/A Lakesuperior 1.0a17 104ms (21%) 104ms (273%) 5.3Gb (40%) 0m17.0s (13%) 0m12.481s 3810ms Lakesuperior 1.0a18 79ms (15%) 79ms (207%) 7.5Gb (58%) 0m14.2s (11%) 0m4.214s** 905ms ========================= =============== ============= ============= =============== ============ ================ \* POST was stopped at 50K resources. From looking at ingest timings over time we can easily infer that ingest time would further increase. This is the manifestation of the "many members" issue. The "Store" value is for the PUT operation which ran regularly with 100K resources. \*\* Timing based on a warm cache. The first query timed at 0m22.2s. .. _ole-workhorse-server-1: ‘Ole Workhorse’ server ~~~~~~~~~~~~~~~~~~~~~~ 10K Resources ^^^^^^^^^^^^^ ========================= ============== ============== ============== ============== ================== System PUT Store GET SPARQL Query Py-API retrieval ========================= ============== ============== ============== ============== ================== FCREPO / Modeshape 4.7.5 285ms (100%) 3.7Gb (100%) 9.6s (100%) N/A N/A Lakesuperior 1.0a17 446ms 298Mb 5.6s (58%) 0m1.194s Not measured Lakesuperior 1.0a18 Not measured Not measured Not measured Not measured Not measured ========================= ============== ============== ============== ============== ================== Conclusions ----------- Lakesuperior appears to be markedly slower on writes and markedly faster on reads. Both these factors are very likely related to the underlying LMDB store which is optimized for read performance. In a real-world application scenario, in which a client may perform multiple reads before and after storing resources, the write performance gap may decrease. A Python application using the Python API for querying and writing would experience a dramatic improvement in reading timings, and somewhat in write timings. Comparison of results between the laptop and the server demonstrates that both read and write performance ratios between repository systems are identical in the two environments. As it may be obvious, these are only very partial and specific results. They should not be taken as a thorough performance assessment. Such an assessment may be impossible and pointless to make given the very different nature of the storage models, which may behave radically differently depending on many variables.