Every release of the chronoskin query engine, with the reasoning behind it. A new version most Thursdays.
One e-mail per release, no marketing.Or take the feed
v4.2.0 Minor
Streaming query plans, and a planner that no longer guesses.
We replaced fixed selectivity constants with sampled histograms. The slowest one percent of queries got four times faster, and two got slower. Here is why.
Plans 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.
Idle connections are closed after the timeout you set, not the default. Fixes a leak seen under bursty load.
A lock was held across the whole batch. It is now taken per page. Read the postmortem for the forty minutes this cost us.
Joins 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.
The upgrade guide walks through the four settings that changed and the one that is gone.
Read the guide# every release, as it ships GET /changelog/feed.xml 200 41 entries
The plan arrives while the query runs, and the planner samples your data instead of assuming its shape.
Until now a plan was something you asked for after a query had been slow. From this release it is a stream you can watch.
Set 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.
@@ planner @@ [planner]- selectivity = 0.1- join_batch = 256+ statistics = "sampled"+ sample_rate = 0.01 timeout = "30s"@@ session @@ [session]+ plan.stream = true
| 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 |
$ chronoskin upgrade 4.2.0 checking 4 settings ok no manual steps $ chronoskin restart --rolling
4.3.0-rc.1 already has everything on this page, plus partial indexes behind a flag.
See the next lineAll 41 versions of the last twelve months, with what each one added, changed and fixed.
By e-mail or by feed. Choose what you hear about and how often.
Security releases are always sent. They ignore the frequency you pick below.
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# all releases /changelog/feed.xml # one release line /changelog/4.x/feed.xml # security releases only, as JSON /changelog/security.json $ curl -s chronoskin.dev/changelog/latest | jq .version
Every release and the engineering notes, to one address. The last e-mail was v4.2.0 on 13 March.
You will stop getting releases and notes. Security releases stop too.