- status: done in the story frontmatter (was the non-conventional
"complete"; the board's axis uses done/in-progress/pending/hold)
- board row 11: what landed, the WO_WAL_UPDATE correction, the ceiling
removed as unreachable, and the one criterion still weaker than
written (expected value, not a resident: all oracle)
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
(cherry picked from commit de39a88e81e97bf6f8b75e9f15331aae20f7ab29)
- flattened row image is WO_WAL_UPDATE, not WO_WAL_INSERT: the row's
original INSERT is already in a live log, so a second one for the same
id is a duplicate replay refuses as corruption. INSERT is right only
for compaction, which builds a fresh log
- remove WO_CKPT_MAX_GARBAGE: with the absolute term at 64 MiB, garbage
large enough to reach a 256 MiB ceiling has already tripped it, so the
branch was unreachable. Postgres needs both constants because it
thresholds on tuples with its pair at opposite ends; this thresholds
on bytes, where one constant does both jobs
- test_delta_chain_flattens_at_k: chain depth stays <= WO_DELTA_MAX_HOPS
across 2K+2 updates, and a reset is observed
- test_delta_chain_flatten_replays: a flattened chain replays correctly
- test_keys_resident_indexed_across_flatten: a delta on an indexed
column composes with flattening, checked at every step across the
bound and after restart. Found no product defect
- test_should_compact_absolute_and_ceiling: pins the absolute term, the
boundary just under it, and the small-log case the ratio still governs
- test_wal 5700 pass / 0 fail; wovm-test and woc-test green
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
(cherry picked from commit f93b5d9db753305c297e868d977670e6d703684c)
TESTS DELIBERATELY HELD at the developer's instruction — logic only.
The existing suite passes (36 suites, 0 fail) but exercises NEITHER new
behaviour: nothing builds a 16-deep chain, and no checkpoint test uses a
log near 64 MiB. Green here means "did not break what existed".
- tier 1: wo_wal_fold_row_at gains hops_out. The walk already visits
every hop, so the depth is free — this is the design's pd_prune_xid,
a cheap "is work worth doing" hint taken from work already happening
- the update path branches on it: past WO_DELTA_MAX_HOPS (16) it writes
a full-row image instead of a delta, terminating the chain. `r`
already holds the complete post-update row because index maintenance
required folding it, so flattening costs bytes, not an extra read
- wo_wal_append_row_image encodes from a caller-held row, as
WO_WAL_INSERT: a chain's base must replay into a database where
nothing precedes it, so replay/compaction/fold need no change
- tier 2: should_compact gains a TRIGGERING absolute term and a ceiling.
Our `floor` SUPPRESSES on a small log — the opposite of postgres's
vac_base_thresh, which triggers on a small absolute problem the
proportion hides. We had the proportion and the suppressor and
neither real guard
- verified by construction, not test: both update entry points converge
on row_apply_field_keys; db.c captures next_offset BEFORE calling in,
so the re-point is transparent to which record type was written
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
(cherry picked from commit 1b808abd5942de81c3a6416714d1302384103040)
- fixes a limitation iteration 2 shipped: compaction was supposed to
bound chain length, but wo_wal_should_compact triggers on a whole-log
byte ratio and cannot see one hot row's chain
- tier 1, flatten on update: the update path ALREADY folds the row for
index maintenance and the fold already walks hop by hop, so it reports
depth for free. Past a fixed K it writes a full row instead of a
delta. Read <= K+1 reads, replay O(K^2) per row. No format change, no
per-row RAM, no new trigger
- tier 2: our compaction policy has a proportional term and a
SUPPRESSOR misleadingly called a floor; postgres's floor TRIGGERS on
small absolute garbage. Add that term and a ceiling
- design read from .dev/reference/postgresql, not recalled:
heap_page_prune_opt gates on an O(1) on-page hint then page fullness
against Max(fillfactor, BLCKSZ/10); autovacuum uses base + scale *
reltuples clamped by a max (50, 0.2, 1e8). Neither thresholds on
new-bytes-versus-old-bytes
- K deliberately does NOT scale with table size: postgres scales a
table-level aggregate with proportional harm, ours is per-row with
additive cost, so scaling up would make big databases boot worst
- the story says plainly it should NOT be next: task 7 has still never
measured whether resident: keys beats the kernel's own paging
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
(cherry picked from commit f667cad2cfbe187b5973440ab1af015b2df288f8)
