UDFS_STATISTICS
Records aggregate information about file-system operations.
Records aggregate information about file-system operations. This table records information about the Linux, S3, and WebHDFS file systems, and records information about metadata (but not data) for the Libhdfs++ file system.
An operation can be made up of many individual read, write, or retry requests. SUCCESSFUL_OPERATIONS and FAILED_OPERATIONS count operations; the other counters count individual requests. When an operation finishes, one of the OPERATIONS counters is incremented once, but several other counters could be incremented several times each.
The following query gets the total number of metadata RPCs for Libhdfs++ operations:
=> SELECT SUM(metadata_reads) FROM UDFS_STATISTICS WHERE filesystem = 'Libhdfs++';
| Column Name | Data Type | Description |
|---|---|---|
| FILESYSTEM | VARCHAR | Name of the file system, such as S3 or Libhdfs++. |
| SUCCESSFUL_OPERATIONS | INTEGER | Number of successful file-system operations. |
| FAILED_OPERATIONS | INTEGER | Number of failed file-system operations. |
| RETRIES | INTEGER | Number of retry events. |
| METADATA_READS | INTEGER | Number of requests to read metadata. For example, S3 list bucket and HEAD requests are metadata reads. |
| METADATA_WRITES | INTEGER | Number of requests to write metadata. For example, S3 POST and DELETE requests are metadata writes. |
| DATA_READS | INTEGER | Number of read operations, such as S3 GET requests to download files. |
| DATA_WRITES | INTEGER | Number of write operations, such as S3 PUT requests to upload files. |
| DOWNSTREAM_BYTES | INTEGER | Number of bytes received. |
| UPSTREAM_BYTES | INTEGER | Number of bytes sent. |
| OPEN_FILES | INTEGER | Number of currently-open files on S3 or WebHDFS file systems. This value will be 0 for other file systems. |
| MAPPED_FILES | INTEGER | Number of currently-mapped files on S3 file systems. This value shows the number of streaming connections for reading data from S3. This value will be 0 for non-S3 file systems. |
| READING | INTEGER | The number of currently-running read operations from S3 or WebHDFS. This value will be 0 for other file systems. |
| WRITING | INTEGER | The number of currently-running writer operations to S3 or WebHDFS. This value will be 0 for other file systems. |