Every release of the chronoskin query engine, with the reasoning behind it. A new version most Thursdays.
\nOne e-mail per release, no marketing.Or take the feed
\nv4.2.0 Minor
\nStreaming query plans, and a planner that no longer guesses.
\nWe replaced fixed selectivity constants with sampled histograms. The slowest one percent of queries got four times faster, and two got slower. Here is why.
\nPlans are sent to the client while the query runs, so a slow step shows up before the result does. The planner now samples instead of assuming.
\n \nIdle connections are closed after the timeout you set, not the default. Fixes a leak seen under bursty load.
\n \nA lock was held across the whole batch. It is now taken per page. Read the postmortem for the forty minutes this cost us.
\n \nJoins on integer keys run in batches of 1,024 rows. The join_batch setting from 4.0 is deprecated and will be removed in 5.0.
\n \nThe upgrade guide walks through the four settings that changed and the one that is gone.
\n Read the guide\n# every release, as it ships\nGET /changelog/feed.xml\n200 41 entries\n
The plan arrives while the query runs, and the planner samples your data instead of assuming its shape.
\nUntil now a plan was something you asked for after a query had been slow. From this release it is a stream you can watch.
\nSet plan.stream on a session and every step reports its row count and timing as it finishes. The driver exposes it as an iterator, so no polling is needed.
--explain-live flag in the command line clientThe sample rate defaults to 1 percent. Tables under 10,000 rows are read in full.
\n@@ planner @@ [planner]- selectivity = 0.1- join_batch = 256+ statistics = \"sampled\"+ sample_rate = 0.01 timeout = \"30s\"@@ session @@ [session]+ plan.stream = true\n
| Package | From | To | Size | Change |
|---|---|---|---|---|
| chronoskin-server | 4.1.3 | 4.2.0 | 18,420 | +212 |
| chronoskin-planner | 4.1.3 | 4.2.0 | 3,904 | +388 |
| chronoskin-cli | 4.1.0 | 4.2.0 | 6,118 | +41 |
| driver-node | 7.3.1 | 7.4.0 | 212 | +9 |
| driver-go | 2.8.0 | 2.9.0 | 1,046 | -17 |
\n Source\n Milestone\n Compare with 4.1.3\n Report a regression\n
\n$ chronoskin upgrade 4.2.0\nchecking 4 settings\nok no manual steps\n$ chronoskin restart --rolling\n
4.3.0-rc.1 already has everything on this page, plus partial indexes behind a flag.
\n See the next line\nAll 41 versions of the last twelve months, with what each one added, changed and fixed.
\n| Version | Title | Kind | Date | Changes |
|---|---|---|---|---|
| v4.2.0 | Streaming query plans | Minor | 13 Mar 2025 | 46 |
| v4.1.3 | Connection pool fixes | Fix | 27 Feb 2025 | 6 |
| v4.1.2 | Slow writes on large batches | Fix | 13 Feb 2025 | 2 |
| v4.1.1 | Timezone names in exports | Fix | 6 Feb 2025 | 4 |
| v4.1.0 | Vectorised hash joins | Minor | 30 Jan 2025 | 31 |
| v4.0.4 | Replica lag reporting | Deprecation | 16 Jan 2025 | 12 |
| v4.0.3 | Index builds resume after restart | Fix | 9 Jan 2025 | 7 |
When one ships it is listed here first and sent to every subscriber the same hour.
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\n# all releases\n/changelog/feed.xml\n# one release line\n/changelog/4.x/feed.xml\n# security releases only, as JSON\n/changelog/security.json\n$ curl -s chronoskin.dev/changelog/latest | jq .version\n
Every release and the engineering notes, to one address. The last e-mail was v4.2.0 on 13 March.
\n \nYou will stop getting releases and notes. Security releases stop too.
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