[I] Object store cache key drops the ABFS container, so two containers in one storage account share a store instance [datafusion-comet]

["andygrove (via GitHub)" <gi...@apache.org>]

andygrove opened a new issue, #4993:
URL: https://github.com/apache/datafusion-comet/issues/4993

   ## Describe the bug
   
   `prepare_object_store_with_configs` in `native/core/src/parquet/parquet_support.rs` caches object store instances under `(url_key, config_hash)`, where `url_key` is built from:
   
   ```rust
   let url_key = format!(
       "{}://{}",
       scheme,
       &url[url::Position::BeforeHost..url::Position::AfterPort],
   );
   ```
   
   `Position::BeforeHost` starts *after* the URL userinfo. For ABFS, the container is the userinfo, not the host:
   
   ```
   abfss://container@account.dfs.core.windows.net/path/to/file.parquet
   ```
   
   So `abfss://c1@acct.dfs.core.windows.net/...` and `abfss://c2@acct.dfs.core.windows.net/...` both produce the key `abfss://acct.dfs.core.windows.net`. `config_hash` is computed over the per-session Hadoop config map, which does not vary by container, so it does not disambiguate them either.
   
   Meanwhile `MicrosoftAzureBuilder::parse_url` bakes the container into the store instance from the URL userinfo, and the `Path` handed to that store is container-relative (the bucket/container is stripped by `Path::from_url_path(url.path())` in `PhysicalPlanner::get_partitioned_files`).
   
   The consequence: within one executor process, reading `abfss://c2@acct/data/f.parquet` after `abfss://c1@acct/data/f.parquet` should hit the cached `c1` store and read **c1's data**.
   
   ## Steps to reproduce
   
   Not yet reproduced. This was found by code reading during review of an unrelated change. Confirming it needs an Azure storage account with two containers holding same-named paths, read from a single executor in one application.
   
   ## Expected behavior
   
   Each ABFS container resolves to its own object store instance, and a read from one container never returns another container's data.
   
   ## Additional context
   
   - S3, GCS, and HDFS are unaffected: their bucket/host lives in the URL host component, which `url_key` does keep.
   - The same key derivation is now also used to key a shared Parquet metadata cache, where the impact is narrower (entries are additionally validated against file size and modification time). That is documented as a known limitation there; this issue is about the store cache itself, where no such validation exists.
   - The object store cache is process-wide and unbounded by design, so a wrong entry persists for the executor's lifetime.


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Re: [I] Object store cache key drops the ABFS container, so two containers in one storage account share a store instance [datafusion-comet]

["sunchao (via GitHub)" <gi...@apache.org>]

sunchao closed issue #4993: Object store cache key drops the ABFS container, so two containers in one storage account share a store instance
URL: https://github.com/apache/datafusion-comet/issues/4993


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Re: [I] Object store cache key drops the ABFS container, so two containers in one storage account share a store instance [datafusion-comet]

["peterxcli (via GitHub)" <gi...@apache.org>]

peterxcli commented on issue #4993:
URL: https://github.com/apache/datafusion-comet/issues/4993#issuecomment-5093117881

   let me take a stab at this.


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