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TERRACOTTA *

  • Hibernate

      ...

        • cache raw compenent types, no objects

      ...

        • 1st level cache (tied to db connection, goes away when db connection
          goes away)

      ...

        • 2nd level cache (avoid going back to db, pluggable, ehcache most
          common, terracotta another option)

          ...

              • needs to be across cluster for writing data

          ...

          • ehcache

              ...

                • option for clusterwide Hibernate 2nd cache

              ...

                • uPortal boxes all have to talk to eachother, get 5-10 becomes

              ...

                • problem, exponentially chatty

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              • Terracotta (open source)

                  ...

                    • option for clusterwide Hibernate 2nd cache

                      ...

                          • could use it directly as well

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                        • advantages

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                        • in clustering,

                      ...

                        • sharding 
                          • separate service, not run on uPortal boxes

                      ...

                          • less "chatty", all uPortal boxes talk to same terracotta box, this
                            allows "sharding" (see below)

                      ...

                          • keeps data as Hibernate 2nd level objects (however those are done),

                      ...

                          • like a shared memory for all uPortal boxes, "network attached memory" (like

                      ...

                          • NAS for memory)

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                          • mark a particular part of application object as "distributed"

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                          • could be called an object oriented db, persists all of its cache to disk

                      ...

                          • data persists until orphaned, then its garbage collection

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                        • use to cluster Tomcat http sessions

                          ...

                              • does it better that Tomcat own session clustering for same
                                "chattiness" issue

                          ...

                              • still doesn't get around serializable requirement, but has config

                          ...

                              • option in case you can't serialize in Java code

                          ...

                            • Big Savings: "sharding", only possible with terracotta's less-chatty architecture,

                          ...

                            • terracotta will only push one box's cache to other boxes when other

                          ...

                            • boxes look for it
                            • ? should people worry about clustering with uPortal?

                          ...

                            • Cris doesn't see big value to clustering http options, e.g. Madison

                          ...

                            • only gets 1.7 requests per login, little chance for failover there

                          ...

                            • important for Sakai, e.g. things go boom in the middle of an exam

                          ...

                            • UofC will be in between

                          ...

                            • uPortal, 2nd level Hibernate cache for layout

                          ...

                            • trend in uPortal has been that session cache is becoming more

                          ...

                            • serializable

                          ...

                          • Stuff going on

                              ...

                                • Sakai

                                  ...

                                      • Cris used in Sakai instance for John Wiley&Son, will be part of
                                        Sakai 2.7 (code freeze Nov. 20 to meet late Winter/early Spring release)

                                  ...

                                      • capabilities will be in Sakai, up to implementers to turn it on

                                  ...

                                      • with it on you should be able to fail over without having to log back in

                                  ...

                                      • for app specific things, e.g. an exam, you can terracotta-enable

                                  ...

                                      • tool by tool, some tools don't have much state and don't need it

                                  ...

                                    • Hibernate 2nd level thing is huge

                                      ...

                                          • uPortal session is possibility, Eric has been thinking about it

                                      ...

                                          • Cris interested in finding uPortal instance where big gains can be

                                      ...

                                          • made with terracotta

                                      ...

                                        • sidenote: there is a way to plug terracotta behind an ehcache

                                      ...

                                        • terracotta can be used without Hibernate, use configs to cache

                                      ...

                                        • without app even knowing (good and bad)

                                          ...

                                              • "super static" - local static class attr, cluster in terracotta

                                          ...

                                              • config, now static across cluster, not just local JVM

                                          ...

                                            • Webinar on changes made to Sakai October 29th 10:30 am pacific

                                          ...

                                            • possible alternative to db, does data really need to be in a db? e.g. Sakai

                                          ...

                                            • "presence" data

                                          ...

                                            • questions? Talk to Cris, also the Terracotta guys are very accessible