crl-release-26.1: pebble: show blob reference size in compaction events

[RaduBerinde]

pebble: show blob reference size in compaction events

Previously, the per-level size in compaction event log lines reflected
only the sum of the input tables' sizes, e.g.:

L0 [31152773 31152772] (747KB) Score=1.31

This omitted the physical size of any blob references, so the reported
size understated the amount of data the tables actually represent when
value separation is in use.

This change sums the EstimatedPhysicalSize of each table's blob
references and, when non-zero, renders the level size as (x + y),
where x is the table size and y is the blob reference size, e.g.:

L0 [31152773 31152772] (747KB + 1.2MB) Score=1.31

A new TableInfo.EstimatedReferenceSize method is added (mirroring the
existing TableMetadata.EstimatedReferenceSize) since the underlying
blobReferences field is package-private to manifest. Levels without
blob references are unchanged.

Co-Authored-By: roachdev-claude roachdev-claude-bot@cockroachlabs.com

tool/logs: parse blob reference size in compaction log lines

Compaction event log lines now render a level's size as (table + blob)
(e.g. (4.2MB + 1.0MB)) when the input tables reference blob files. The
log parser previously assumed a single size value inside the parentheses:

• The compactionPattern regexp required the closing paren immediately
  after the first size, so the bytes capture (used for the output size
  of an compacted line) matched nothing for the new format.
• sumInputBytes passed the entire parenthesized contents to
  unHumanize, which only understands a single size token.

This change teaches the parser about the optional + <size> suffix. The
regexp now accepts one or more +-separated sizes within the
parentheses, and a new unHumanizeSum helper splits on + and sums the
parts. Both the input-byte and output-byte parsing paths use it, so the
reported sizes include the estimated physical size of blob references.

Co-Authored-By: roachdev-claude roachdev-claude-bot@cockroachlabs.com

[cockroach-teamcity]

This change is 

[sumeerbhola]

@sumeerbhola made 1 comment.
Reviewable status: 0 of 5 files reviewed, all discussions resolved.