[zriyansh]

What this adds

Three new /compare posts and two new /learn explainers. Each comes with a quiz, its images and a social card. No existing post is changed.

Post	URL	Page date
MongoDB Alternatives: 7 Options and Their Limits	/compare/mongodb-alternatives/	19 Oct 2026
Best MongoDB Change Data Capture Tools in 2026	/compare/mongodb-cdc-tools/	21 Oct 2026
Best Oracle Replication Tools in 2026, Compared	/compare/oracle-replication-tools/	22 Oct 2026
Types of Databases, With Examples and Their Limits	/learn/types-of-databases/	2 Oct 2026
What Is Change Data Capture? A Plain Guide (2026)	/learn/what-is-change-data-capture/	3 Oct 2026

• MongoDB alternatives: seven databases compared on limits, cost and fit, and where OLake Go helps when you keep MongoDB and want analytics.
• MongoDB CDC tools: tools that read MongoDB change streams, with their limits (the 16 MB document limit, oplog size, versions) and OLake Go's MongoDB source.
• Oracle replication tools: log-based and batch options for Oracle, with dated prices; OLake Go is listed for scheduled copies of Oracle tables into Iceberg or Parquet.
• Types of databases: a plain explainer of the main database types with examples, limits and licences.
• What is change data capture: a plain explainer of how CDC works across the common databases, and which databases OLake Go captures changes from (Postgres, MySQL and MariaDB, MongoDB, SQL Server).

Notes

• Vendor facts come from each vendor's own pages with the date read. User quotes link to their source.
• Each post has a quiz (src/data/quizzes/) and a social card, with the cover entries added to scripts/og-images.manifest.json.
• Some links point to posts in Add five posts and update post dates #585 (/learn/oltp-vs-olap/, /compare/postgres-vs-mysql/) and resolve once Add five posts and update post dates #585 is merged.
• The sibling PR is Add five posts: Snowflake, streaming, big data #604. Both edit the manifest, so whichever merges second needs a one-line merge of that file (see Post PRs conflict on scripts/og-images.manifest.json #606).

[shubham19may]

Builds and typechecks clean, content only, no concerns on the code side. One editorial point before merge, and it applies to this PR and #604 (same comment there), plus the posts already live.

Review-site quotes. Across these ten posts there are 79 links to Hacker News and PeerSpot, roughly one "What users say" quote per competitor, almost all negative (cost, reliability, support). The nofollow plugin handles the link side. The content side is what I want changed:

1. Quote opinions and first-hand pricing experience only. Never an unverified factual defect ("it loses data", "it does not support X") from an anonymous commenter. If a defect matters, cite the vendor's own docs or issue tracker instead.
2. Balance: for each tool either one positive and one negative quote, or none. A page that quotes only the negatives about every competitor, with OLake underneath, reads as a hit piece, and it gets screenshotted when we later want a partnership or a joint customer with that vendor.
3. Drop the sharpest ones. The kind of line I mean, already live: "Fivetran is convenient but absurdly expensive".
4. Keep the date and the link on every quote, as you already do, and keep the "one person's view" line.

Please apply 1–3 to the ten posts in #604 and #605 before merge, and add the rule to the SOP so it holds for the next batch. The already-published posts can be swept in a follow-up PR.

[shubham19may]

Please remove the third-party screenshots before merge. Decision from our side: we do not want captures of other vendors' pages on olake.io. A screenshot of a vendor's landing, pricing, licence or docs page is a copy of their copyrighted page, including logo and design, and the remedy on their side is a copyright notice to us. We'd rather not carry that exposure across a hundred images, and pricing captures go stale the day the vendor changes a number while staying live on our domain.

What to do in this PR and in #604 (same comment there):

• Remove every image that is a capture of a third-party page: vendor landing pages, pricing pages and plan tables, licence pages, docs pages, limits pages, console views, Hacker News threads. By your naming that is roughly every <post>--<vendor>-*.webp file plus the landing-*, *-pricing*, *-plans*, *-limits*, *-licence*, *-free-tib*, *-rpu-price* files. In this PR that is around 13 to 20 of the 40 non-cover images, every capture of a vendor docs or limits page included.
• Replace each with the same information as text: a dated sentence or a small table with the price or limit and a link to the vendor page. The claim keeps its source, and we can edit it in a minute when the vendor changes it.
• Keep your own diagrams (*-which-fits, *-layers, *-three-routes, *-starts-vs-moves and the like) and any screenshot of OLake's own UI or docs. Those are ours.
• Remove the deleted images' entries from the image sitemap inputs if any, and check the build has no broken image warnings.

Please also add this to the SOP as a rule, and open a follow-up PR that sweeps the posts already live in /compare and /learn (I count roughly a hundred such captures there). That follow-up does not block this merge, but it should land this week.

[shubham19may]

See the monthly refresh skill request on #604; it covers the posts in this PR too once the screenshots are replaced with dated, linked text.

[shubham19may]

Addendum with specifics, from a pass over the five posts against the docs.

OLake claims: all supported, nothing contradicted. The Oracle post correctly says OLake has no Oracle CDC, and the MongoDB posts match the connector docs (change streams, replica set, oplog on, 4.0+, pre-images on 6.0+). Nit: the Apache 2.0 mention in mongodb-cdc-tools.mdx:315 has no link; link the GitHub repo.

Quotes to drop or replace under rule 3 above:

• mongodb-alternatives.mdx:300 Cassandra "an operational nightmare"
• mongodb-cdc-tools.mdx:301 Fivetran "absurdly expensive"
• types-of-databases.mdx:264 MongoDB "I'd never want to admin it again"

Unlinked competitor limits: about 50 lines across these five posts credit a vendor's docs with no hyperlink. Worst is the Oracle post (oracle-replication-tools.mdx:123,177,236,255,271,310,366,401,404,435, and :48, :541 cite "Oracle's paper" with no link), then mongodb-alternatives.mdx:128-132,165,167,195 and mongodb-cdc-tools.mdx:198,263,295,297,387,418-422. A factual limit about a competitor needs its link regardless of the ten-link cap. Link it or cut it.

[zriyansh]

This merged before the review points were applied. They are covered in #609 (quotes, screenshots and unlinked limits for the five posts here and the other live posts) and the OLake nits are in the same PR. The rules are in the SOP in #604.

[zriyansh]

Update: the points above are applied for these five posts in #609 (they are live, so the fixes go there). Please close the revert #608 and merge #609 instead.