Enhancing the Performance and Extensibility of the XC MetadataServicesToolkit Ben Anderson, Software Engineer, XCO

Download this presentation: 2

Timeline 3 Jennifer Bowen presented at code4lib 2/10 I began at XCO 3/10 work began on 0.3 4/ released 1/ released 1.0 released

MARCXML (6M records) DC-TERMS (13k records) XC Software Components User Interface for searching and browsing Library Website (on Drupal) Integrated Library System Repository XC Drupal Toolkit Tools for automated processing of large batches of metadata XC Metadata Services Toolkit Tools for connectivity between XC and an ILS XC Circ. Status/Req. Authentication XC NCIP Toolkit 4 XC OAI Toolkit irplus

5

Learn More about XC at 6

One Example of Process Flow 7 MARC BIB record from external repository Normalized MARC BIB record from normalization service FRBRized records from transformation service work expression manifestation

M S T Logical Process 8 OAI-PMH Harvest MARC Normalization Service MARC-XC Transformation Service Pseudo OAI-PMH Harvests OAI-PMH Harvestable provider caches repo

Add an External Repository 9

Schedule a Harvest 10

Configure Processing Rules 11

Browse Records 12

Goals for 0.3 Each service should process one million records per hour on an “average library server” – 1.5 GHz SPARC V9 – 8G RAM (3G for the JVM) – 10k RPM hard drive Services should have little to no degradation as the size of a repository grows – University of Rochester has 6M records Implementing a service should be easy – it should require no knowledge of MST internals – it should not be up to the service implementer to figure out how to build and package their service 13

Determine Throughput of 0.2 Using the MARC Normalization service as our metric, the first million records processed at average at a speed of: – 29 ms/record = 120k/hr (goal is 3.6 ms/rec = 1M/hr) Before the service processed 2 million records, the process crawled to a halt (goal was little to no degradation of at least 6 million records). 14

Determine Bottlenecks with TimingLogger 15 This code produces this output

Bottleneck Breakdown 29 ms per record – 2.5 ms to create DOM – 5 ms for actual service processing (the innards of the MARC-Normalization service) – 21 ms for querying solr and inserting This is the average - both querying and inserting are done in batch. I had a hard time separating the two 16

0.2 Design 17 All data needed for the UI except for searching and browsing records All data needed for configuring harvests, services, processing rules, etc Text indexes necessary for searching and browsing records All record/repository data

0.3 Design Change to use MySQL 18 All data needed for the UI except for searching and browsing records All data needed for configuring harvests, services, processing rules, etc All record/repository data Doesn’t store any data Use only for indexing records to support searching in the UI

0.3 Design – Keep the table sizes small 19 One index for all repositories Each external repository cache and each service gets its own set of database tables external provider repo normalization repo transformation repo

one or more per record zero or more per record one per record 0.3 Design - Yes, a boring ERD 20 record_updates record_id update_date records_xml record_id xml record_sets records_xml record_id xml record_predecessors record_id pred_record_id

Did that improve things? ms per record (previously 29) – 2.5 ms to create DOM – 5 ms for actual service processing (the innards of the MARC-Normalization service) – 3.5 ms (previously 21) for querying MySQL and inserting into MySQL again, both querying and inserting are done in batch The query time is almost nill - it’s the inserting that takes time. It’s faster, but still nearly 3x slower than our goal The performance showed little to no degradation

Get rid of XPath 22 XPath isn’t a bad technology, but when you’re optimizing for performance, it can be beneficial to find other ways to accomplish the same task. So, I changed this code… to this code…

Did that improve things? 23 7 ms per record (previously 11) – 2.5 ms to create DOM – 1.0 ms (previously 5) for actual service processing (the innards of the MARC-Normalization service) – 3.5 ms for MySQL inserts It’s faster, but still nearly 2x slower than our goal

Delayed Indexing in MySQL MySQL modifies table indexes with each insert. It is faster to the drop indexes, insert lots of rows into the tables, and then add the indexes back. – This is the way mysqldump works – This means you can’t read the data while doing an insert. No big deal – we’ll just do it during large loads. 24

Did that improve things? 25 6 ms per record (previously 11) – 2.5 ms to create DOM – 1.0 ms for actual service processing (the innards of the MARC-Normalization service) – 2.2 ms (previously 3.5) for MySQL inserts It’s faster, but still nearly 2x slower than our goal

Batch Prepared Statements 26 Java/JDBC provides an extremely highly performant method for sending large chunks of data to the db at once using batch prepared statements. There’s no way to speed this part up… or so I thought…

LOAD DATA INFILE 27 When discussing db optimizations with XC’s Drupal Toolkit developer, Peter Kiraly, he said PHP didn’t have the same ability. Instead he’d have to write out a csv file and load that in. I figured I might as well try it.

Did that improve things? 28 4 ms per record (previously 6) – 2.5 ms to create DOM – 1.0 ms for actual service processing (the innards of the MARC-Normalization service) – 0.6 ms (previously 2.2) for MySQL inserts Pretty close, but still not there

Sometimes it’s the little things 29 DomFactoryBuilderDOAServiceFactoryFactoryImpl I knew enough not to create the DocumentBuilderFactory each time, but didn’t realize creating the DocumentBuilder each time would have that much of an effect. Code was Code is now

Did that improve things? 30 3 ms per record (previously 4) – 0.9 ms (previously 2.5) to create DOM – 1.0 ms for actual service processing (the innards of the MARC-Normalization service) – 0.6 ms for MySQL inserts WE DID IT! We have exceeded our goal!

0.2 Service Development 31 Internals of the MST were exposed to the service developer and the developer was expected to re-implement much of this internal code.

code.google.com/p/xcmetadataservicestoolkit/ 32

0.3.x Service Development Install Java, Ant, MySQL 33 $ wget ' $ unzip example dev-env.zip $ cd example $ ant retrieve $ ant -Dtest=ProcessFiles test $ ls -ladh./build/test/actual_output_records/1/* $ ant zip

Input Files for Testing $ ls -1./test/input_records/1/* | xargs cat oai:mst.rochester.edu:bib:1 pb&j oai:mst.rochester.edu:bib:1 pb&j

Output Files from Testing $ ls -1./build/test/actual_output_records/1/* | xargs cat oai:mst.rochester.edu:example/1 oai:mst.rochester.edu:bib:1 pb&j you've been foobarred! 35

Implementing in Code 36

More tidbits for interested implementers The MST now is configured via spring – each service is given it’s own application context as well as it’s own classloader This means it can use all the objects and services from the MST while not worrying about name collisions (naming or dependencies) w/ other services Each service is given it’s own db schema (again, so you don’t have to worry about name collisions). The db schema is prefixed w/ “xc_” 37

Other Services MARC-XC-Transformation Just as fast as the marcnormalization service DC-XC-Transformation Initially contributed by Kyushu University (in Japan) – now one of our core services. 38

Photo Credits All photos taken from flickr.com – “Brick Wall” by somenametoforget – “Snail” by DRB62 – “Paris Train” by Pictr 30D – “Spaghetti with tomato sauce” by HatM – “Hawk in Flight” by Nick Chill – “Tortoise” by GraphicReality 39

Final Numbers k records / hr 29 ms / record fell down before 2M records processed not easily extensible M records / hr 3.0 ms / record processed 16M records with no degradation easily extensible 1.5 GHz CPU

Download XC software at eXtensibleCatalog.org contact me at