I think there are two ways to do this: 1. As Xuanwo said, we refactor HadoopCatalog to be read only, and throw unsupported operation exception for other operations that manipulate tables. 2. Totally deprecate HadoopCatalog, and add StaticTable as we did in pyiceberg or iceberg-rust.
On Thu, Jul 18, 2024 at 11:26 AM Xuanwo <xua...@apache.org> wrote: > Hi, Renjie > > Are you suggesting that we refactor HadoopCatalog as a FileSystemCatalog > to enable direct reading from file systems like HDFS, S3, and Azure Blob > Storage? This catalog will be read-only that don't support write operations. > > On Thu, Jul 18, 2024, at 10:23, Renjie Liu wrote: > > Hi, Ryan: > > Thanks for raising this. I agree that HadoopCatalog is dangerous in > manipulating tables/catalogs given limitations of different file systems. > But I see that there are some users who want to read iceberg tables without > relying on any catalogs, this is also the motivational use case of > StaticTable in pyiceberg and iceberg-rust, is there similar things in java > implementation? > > > On Thu, Jul 18, 2024 at 7:01 AM Ryan Blue <b...@apache.org> wrote: > > Hey everyone, > > There has been some recent discussion about improving > HadoopTableOperations and the catalog based on those tables, but we've > discouraged using file system only table (or "hadoop" tables) for years now > because of major problems: > * It is only safe to use hadoop tables with HDFS; most local file systems, > S3, and other common object stores are unsafe > * Despite not providing atomicity guarantees outside of HDFS, people use > the tables in unsafe situations > * HadoopCatalog cannot implement atomic operations for rename and drop > table, which are commonly used in data engineering > * Alternative file names (for instance when using metadata file > compression) also break guarantees > > While these tables are useful for testing in non-production scenarios, I > think it's misleading to have them in the core module because there's an > appearance that they are a reasonable choice. I propose we deprecate the > HadoopTableOperations and HadoopCatalog implementations and move them to > tests the next time we can make breaking API changes (2.0). > > I think we should also consider similar fixes to the table spec. It > currently describes how HadoopTableOperations works, which does not work in > object stores or local file systems. HDFS is becoming much less common and > I propose that we note that the strategy in the spec should ONLY be used > with HDFS. > > What do other people think? > > Ryan > > -- > Ryan Blue > > > Xuanwo > > https://xuanwo.io/ > >
