Issue Summary

The comment in the codebase for the block_free statistic currently states:

/* Increment the free block statistic when not running salvage. */

However, this comment does not explain the rationale behind excluding salvage operations from incrementing the block_free stat. The salvage operation is a corruption repair process, while compaction and reconciliation/eviction are user-driven activities. The lack of explanation has led to confusion among developers.

Context

• The relevant code snippet is:

  /* Increment the free block statistic when not running salvage. */
  if (!F_ISSET(S2BT(session), WT_BTREE_SALVAGE)) {
      WT_STAT_DSRC_INCR(session, block_free);
  }
  

• The rationale is that salvage is a corruption repair operation and should not be counted as normal block freeing, which is typically due to user activity (compaction, reconciliation, eviction).
• The current comment does not clarify this distinction.

Proposed Solution

Update the code comment to clearly state why salvage is excluded from incrementing the block_free statistic, specifically noting that salvage is a corruption repair operation and not user-driven.

Original Slack thread: Slack Thread
This ticket was generated by AI from a Slack thread.