At present, the file system based catalogues have the following problems (this is what I can think of at the moment, perhaps not comprehensive). 1. does not support renaming operations 2. commit does not support atomicity 3. atomic delete (sorry I don't understand why we need it?What scenarios need this?)? 4.Some features are missing, such as: support for views.
We have solved issue 2, and issue 1 is tolerated by users for the time being. Regarding issue 3, we don't know what the specific problem is that it relates to. From what I've seen so far, I think most of the problems can actually be solved.Filesystem-based catalogues can achieve at least a read-commit level of isolation.For OLAP systems, it is sufficient for most scenarios. I'm not sure if I'm being overly optimistic about this issue, so please let me know if there's anything wrong with my opinion.Thank you. 在 2024-07-13 02:07:42，"Ryan Blue" <b...@databricks.com.INVALID> 写道： I think one of the main questions is whether we want to support locking strategies moving forward. These were needed in early catalogs that didn't have support for atomic operations (HadoopCatalog and GlueCatalog). Now, Glue supports atomic commits and we have been discouraging the use of HadoopCatalog, which is a purely filesystem-based implementation for a long time. One thing to consider is that external locking does solve a few of the challenges of the filesystem-based approach, but doesn't help with many of the shortcomings of the HadoopCatalog, like being able to atomically delete or rename a table. (Operations that are very commonly used in data engineering!) Maybe we should consider moving Hadoop* classes into a separate iceberg-hadoop module, along with the LockManager to make it work somewhat better. Personally, I'd prefer deprecating HadoopCatalog and HadoopTableOperations because of their serious limitations. But moving these into a separate module seems like a good compromise. That would also avoid needing to add dependencies to core, like Redis for lock implementations. Ryan On Thu, Jul 11, 2024 at 10:42 PM lisoda <lis...@yeah.net> wrote: Currently, the only lockManager implementation in iceberg-core is InMemoryLockManager. This PR extends two LockManager implementations, one based on the Redis, and another based on the Rest-API. In general, most users use redisLockManager is sufficient to cope with most of the scenarios, for redis can not meet the user's requirements, we can let the user to provide a RestApi service to achieve this function. I believe that, for a long time, these two lock-manager's will satisfy most of the customer's needs. If someone could review this PR, that would be great. PR: https://github.com/apache/iceberg/pull/10688 SLACK: https://apache-iceberg.slack.com/archives/C03LG1D563F/p1720761992982729 -- Ryan Blue Databricks
