17.00 - File System: Data Block Merge Columns - Teradata Database

Teradata Vantageā„¢ - Resource Usage Macros and Tables

Advanced SQL Engine
Teradata Database
June 2020
User Guide

These columns merge small data blocks into one large block so that subsequent merge attempts will have less I/Os.

Column Name Mode Description Data Type
DBMergeDone count Number of successful data block merges done. The number of times the data block being modified successfully merged with some number of adjacent data blocks as part of the modification.

Subtracting DBMergeDone from DBMergeTried will result in the number of data block merge operations that were tried and failed.

DBMergeElim count Number of data blocks eliminated due to data block merges. If n data blocks are merged into one large block, where n is the number of data blocks, this number is incremented by n-1. FLOAT
DBMergeExtraIO count Number of additional physical I/Os performed in the data block merge process over and above those done if no data block merges were attempted. This includes any extra physical I/Os that were performed regardless of whether a particular merge attempt succeeded or not. FLOAT
DBMergeTried count Number of times the data block being modified tried to be merged with adjacent data blocks as part of the modification. FLOAT