Content Hosting Conversion (2.x)

Migrating from 2.4 to 2.5 requires adding several columns to the database tables used by the Content Hosting Service (the service used by the Resources tool, Dropbox, filepicker and WebDAV). The conversion scripts contain DDL statements to accomplish those changes. You need to run these conversions scripts (or perform the equivalent operations manually) and then convert your existing Resources via one of the methods outlined below, before you will gain the performance improvements Sakai 2.5 offers.

The new columns added to the database tables support a switch from XML serialization to "binary-entity" serialization, and enable Resources to perform faster and use less memory. One of the key areas this impacts is improving the performance of quota calculations.

There are two methods for converting existing Resources, with the first being the recommended option, as it enables all performance improvements when completed:

1. Run the conversion utility, which can be run on a live system. (See readme for more details.)
   • Systems running oracle should read the email threads copied to the comments section below.
2. Let the code convert each Resource as it is accessed.
   • This is only recommended for implementations with small datasets, such as pilot deployments; otherwise you should use the above conversion utility.
   • While some performance benefits from the binary-entity serialization can be realized immediately using this method, others, such as the quota calculation improvements will not be available until all Resources have been accessed and converted.

Based on the state of the data in the Content Hosting Service tables, it will start up in one of two modes:

1. Binary only - If the code detects on start-up that all of the XML fields are null – as would be the case after running the conversion utility – it will run in binary mode. The means the system will only read and write using binary-entity serialization, and you will be able to fully realize all the performance enhancements that it offers.
2. Dual mode - If the code detects there is still data in the XML fields – as would be the case if the conversion utility has not be run – it will run in dual mode. This means the system will be capable of reading both XML-serialized and binary-entity-serialized resources, but will write using only binary, and will convert any XML data it encounters into binary data. This gives you some of the performance benefits of binary-entity serialization without running the conversion utility, but you will never get the quota-calculation improvements unless all Resources end up converted.