cmaven

Worknotes

:bulb: SEO Series Part 2. Part 1 covered post-level frontmatter, jekyll-seo-tag, and permalink optimization. After that, however, even after pushing several new posts, Google Search Console’s sitemap.xml Last read date stayed frozen for weeks and new posts were not getting indexed. Before reaching for generic explanations (crawl budget, content quality), this repository had a concrete code-level problem: missing settings in _config.yml. This post walks through the diagnosis and the fix.

:bulb: SEO Series Layout

  • Part 1 — Post-level SEO: frontmatter, jekyll-seo-tag, permalink and filename
  • Part 2 (this post) — Making sitemap refresh properly: _config.yml url/future/timezone — 3-line diagnosis and fix
  • Part 3 — Site-wide SEO audit: sitemap quality, verification meta tags, bulk description fix, 404/archive cleanup
  • Part 4 — Cleaning up Google Search Console residuals: diagnosing 404/redirect/”crawled-not-indexed” and applying noindex meta tags

Environment: Jekyll 3.x + minimal-mistakes + GitHub Pages + jekyll-sitemap plugin

[01] The Problem

After pushing several new posts, Google Search Console (GSC) showed these two symptoms continuously.

graph LR
    PUSH["push new posts"] -->|1~2 weeks later| GSC["Check Search Console"]
    GSC --> SITEMAP["Sitemap
Last read not refreshed"]
    GSC --> INDEX["Indexed pages
new posts missing"]

    style PUSH fill:#e3f2fd,stroke:#1565c0
    style SITEMAP fill:#ffcccc,stroke:#c62828
    style INDEX fill:#ffcccc,stroke:#c62828
Symptom Expected Actual
Sitemap last read refresh at least weekly stuck for weeks
Indexed page count reflects new posts only old posts
sitemap.xml contents latest posts included possibly missing

[02] Generic Explanations First (Common AI Answers)

Most answers list these 7 generic causes. They are not wrong, but you should inspect your own repository configuration first.

# Cause Verdict
1 Site rarely changes Normal — not the problem
2 Low lastmod reliability (all identical / no real changes) Worth checking
3 Low crawl priority (new domain, low traffic) Time-based resolution
4 robots.txt / redirects / access errors Worth checking
5 No change detected vs previous sitemap Normal
6 Crawl budget limits Scale-related
7 Search Console UI lag Ignorable

:warning: The 7 above are generic. The actual cause for this repository was different. The next section walks through the diagnosis.

[03] Actual Root Cause Diagnosis

Inspecting _config.yml revealed 3 critical missing settings.

graph TD
    ROOT["sitemap stalled — causes"] --> C1["(1) url: empty
→ canonical URL not generated"]
    ROOT --> C2["(2) future: default false
→ today's posts excluded from build"]
    ROOT --> C3["(3) timezone: empty
→ parsed as UTC, KST date boundary misjudged"]

    C1 --> R1["Sitemap URL incomplete
Google trust drops"]
    C2 --> R2["New posts simply absent
from _site/"]
    C3 --> R3["2026-04-15 post seen as
future when converted to UTC"]

    style ROOT fill:#fff3e0,stroke:#e65100
    style C1 fill:#ffcccc,stroke:#c62828
    style C2 fill:#ffcccc,stroke:#c62828
    style C3 fill:#ffcccc,stroke:#c62828

3-1. url: Is Empty



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# Before
url                      : # the base hostname & protocol ...
baseurl                  : # the subpath of your site ...
  • jekyll-sitemap generates sitemap.xml’s <loc> absolute URLs from site.url
  • If empty, <loc>/categories/xxx/</loc> ends up as a relative path, or <loc> is missing
  • From Google’s view: “this sitemap looks malformed” → trust drops → recrawl frequency falls
  • jekyll-seo-tag’s canonical and Open Graph URL also fail to generate for the same reason

3-2. future: Flag Not Set (Defaults to false)

By default, Jekyll excludes future-dated posts from the build. Why this is critical:



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# Current time (UTC): 2026-04-15 23:10
# Post frontmatter: date: 2026-04-16

$ jekyll build
# → That post is judged "future" and excluded from _site/
# → Naturally missing from sitemap.xml too

:warning: When timezone is also empty, a post written in the afternoon (KST) gets pushed to the next day in UTC and classified as a future post — an edge case to watch for.

3-3. timezone: Missing



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# Before
timezone: # https://en.wikipedia.org/wiki/List_of_tz_database_time_zones
  • Empty value → Jekyll falls back to the server (or Liquid) default TZ (GitHub Pages builder is UTC)
  • If a post only has date: 2026-04-16, KST 00:00 ≠ UTC 00:00 → date boundary misjudged
  • For stable results, set future: true and timezone: Asia/Seoul together

[04] Fix: 3-Line Change in _config.yml

4-1. Diff



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# Site Settings
locale                   : "ko-KR"
title                    : "Blog"
# ...
- url                      : # the base hostname & protocol for your site
- baseurl                  : # the subpath of your site
+ url                      : "https://cmaven.github.io"
+ baseurl                  : ""

# Outputting
permalink: /:categories/:title/
paginate: 5
paginate_path: /page:num/
- timezone: # https://en.wikipedia.org/wiki/List_of_tz_database_time_zones
+ timezone: Asia/Seoul
+ future: true # include today's and future-dated posts in the build

4-2. Effect of Each Setting

Setting Before After Effect
url (empty) https://cmaven.github.io sitemap <loc> absolute URLs and canonical tags generated
baseurl (empty) "" (explicit empty string) Explicit root-domain hosting
timezone (empty) Asia/Seoul Date interpretation in KST
future (default false) true Today’s and future-dated posts included in build/index

4-3. Verification Sequence

sequenceDiagram
    participant Dev as Author
    participant Repo as GitHub Repo
    participant GHP as GitHub Pages Builder
    participant Site as cmaven.github.io
    participant GSC as Search Console

    Dev->>Repo: push _config.yml change
    Repo->>GHP: Pages build triggered
    GHP->>Site: regenerate _site/sitemap.xml
    Dev->>Site: open sitemap.xml directly (confirm 200 OK)
    Dev->>GSC: resubmit in Sitemaps menu
    GSC->>Site: recrawl sitemap.xml
    GSC-->>Dev: Last read date refreshes

[05] Verification Checklist

After the fix, going through the checklist below in order confirms whether the root cause was actually resolved.

# Check How Expected Result
1 sitemap accessible curl -I https://cmaven.github.io/sitemap.xml 200 OK
2 absolute URLs in sitemap Open sitemap.xml in browser <loc>https://cmaven.github.io/...</loc>
3 latest posts present Search for new post URLs in sitemap body Found
4 lastmod variety Compare <lastmod> values across entries Differ per post
5 robots.txt permits https://cmaven.github.io/robots.txt Sitemap: line present
6 GSC indexing request Search Console → URL Inspection → Request Indexing Acknowledgement message
7 Sitemap resubmission GSC → Sitemaps → resubmit /sitemap.xml “Success” state

[06] Key Lessons

6-1. Check Your Own Config Before Generic Theories

Searching for “sitemap not refreshing” mostly yields generic explanations like “low crawl priority” or “Search Console UI delay”. Those are valid, but checking 3 lines in _config.yml first is faster.

6-2. Jekyll Default Pitfalls

Default Pitfall
future: false TZ shift makes today’s post “future” → missing from sitemap
timezone: (empty) UTC interpretation → KST dates misjudged
url: (empty) minimal-mistakes template ships with it blank

6-3. GSC “Last read” Is a Result Indicator

Sitemap Last read refresh happens when Google judges it worth re-reading. To trigger this:

  • sitemap content must show real changes (url, lastmod)
  • sitemap format must be trustworthy (absolute URLs, correct <loc>)
  • the site must have new/edited content on a steady cadence

:star: This case was not “out of crawl budget” — it was “new posts never made it into the sitemap in the first place”. future: true + url settings are the core fix.

[07] Next in the Series

Once the 3-line _config.yml fix gets the sitemap generating and refreshing correctly, the next step is auditing the sitemap’s contents themselves. The auto-generated sitemap includes not only posts but also low-value archive URLs like category/tag/pagination pages, which can lead Google to judge the entire sitemap as low quality.

Part 3 covers the 5 issues found while auditing the whole repo (low-value URLs mixed in, missing verification meta tags, 9 posts missing description, no 404 page, old C/C++ posts uncleaned) and the bulk fixes. Part 4 then closes out the 4 residual Search Console categories (404 / redirect / crawled-not-indexed / discovered-not-indexed) using noindex meta tags and navigation trailing-slash cleanup.

[08] References

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