') + ')', 'gi'); if (regex.test(text)) { found = true; var frag = document.createDocumentFragment(); var parts = text.split(regex); parts.forEach(function(part, i) { if (i % 2 === 0) { frag.appendChild(document.createTextNode(part)); } else { var span = document.createElement('span'); span.className = 'userscript-highlight'; span.textContent = part; frag.appendChild(span); } }); node.parentNode.replaceChild(frag, node); } }); } else if (node.nodeType === 1 && node.childNodes) { // element var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT']; if (!skipTags.includes(node.tagName)) { Array.from(node.childNodes).forEach(highlight); } } } highlight(document.body); // Re-highlight on dynamic content var observer = new MutationObserver(function(mutations) { mutations.forEach(function(m) { m.addedNodes.forEach(function(node) { if (node.nodeType === 1 || node.nodeType === 3) highlight(node); }); }); }); observer.observe(document.body, { childList: true, subtree: true }); })(); } } catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + ', 'i'); if (__m === '*' || __re.test(location.href)) { // Strip utm_, fbclid, gclid, etc. from all links on page (function() { var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content', 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid', 'ref', 'ref_src', 'source', 'medium', 'campaign']; function cleanUrl(url) { try { var u = new URL(url, window.location.origin); var changed = false; trackingParams.forEach(function(p) { if (u.searchParams.has(p)) { u.searchParams.delete(p); changed = true; } }); return changed ? u.toString() : url; } catch (e) { return url; } } function cleanLinks() { document.querySelectorAll('a[href]').forEach(function(a) { var clean = cleanUrl(a.href); if (clean !== a.href) a.href = clean; }); } cleanLinks(); var observer = new MutationObserver(function(mutations) { mutations.forEach(function(m) { m.addedNodes.forEach(function(node) { if (node.nodeType === 1) { if (node.tagName === 'A') cleanLinks(); node.querySelectorAll('a[href]').forEach(function(a) { var clean = cleanUrl(a.href); if (clean !== a.href) a.href = clean; }); } }); }); }); observer.observe(document.body, { childList: true, subtree: true }); })(); } } catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); } })(); (function(){ try { var __m = "youtube.com"; var __re = new RegExp('^' + "youtube\\.com" + ', 'i'); if (__m === '*' || __re.test(location.href)) { // Auto-enable theater mode on YouTube (function() { function tryTheater() { var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]'); if (btn && !btn.classList.contains('activated')) { btn.click(); } } // Try immediately tryTheater(); // Try after navigation (SPA) var lastUrl = location.href; setInterval(function() { if (location.href !== lastUrl) { lastUrl = location.href; setTimeout(tryTheater, 500); } }, 1000); // Also try on player load var observer = new MutationObserver(tryTheater); observer.observe(document.body, { childList: true, subtree: true }); })(); } } catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + ', 'i'); if (__m === '*' || __re.test(location.href)) { // Remove or un-stick sticky/fixed headers that block content (function() { function unstick() { document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) { if (el.style.position === 'fixed' || el.style.position === 'sticky' || getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') { el.style.position = 'static'; el.style.top = 'auto'; el.style.zIndex = 'auto'; } }); } unstick(); var observer = new MutationObserver(unstick); observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] }); })(); } } catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); } })(); })(); Reduce default API server workers to 1 by jedcunningham · Pull Request #55707 · apache/airflow · GitHub
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Reduce default API server workers to 1 - #55707

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jedcunningham merged 3 commits into
apache:mainfrom
astronomer:workers_to_one
Sep 16, 2025
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Reduce default API server workers to 1#55707
jedcunningham merged 3 commits into
apache:mainfrom
astronomer:workers_to_one

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@jedcunningham

@jedcunninghamjedcunningham commented Sep 16, 2025

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Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server.

With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.

Closes#52270

@jedcunningham
Reduce default API server workers to 1
20e894c
Change the default number of API server workers from 4 to 1 and add
guidance to deploy multiple API servers for scaling instead of
increasing workers per server.
With FastAPI, sync code runs in an external thread pool, making
multiple workers within a single api server less necessary than it was in
our flask days. And with uvicorns new spawn behavior instead of fork,
it means no shared copy-on-write memory between workers, so it's better
to scale horizontally now.
vatsrahul1001
vatsrahul1001 reviewed Sep 16, 2025
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Comment threadairflow-core/src/airflow/config_templates/config.yml Outdated
@jedcunninghamjedcunningham mentioned this pull request Sep 16, 2025
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@jedcunningham

jedcunningham commented Sep 16, 2025

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I should say, I think this is a safer default and (in my testing at least) avoids the timeout problems we've seen in #52270 even in a cpu constrained environment.

My scale testing shows this change is roughly equivalent with 1 core, and a lot faster with half a core (especially for heavier requests).

@kaxilkaxil added this to the Airflow 3.1.0 milestone Sep 16, 2025
@jedcunningham
jedcunningham merged commit 87fc469 into apache:mainSep 16, 2025
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@jedcunningham
jedcunningham deleted the workers_to_one branch September 16, 2025 14:03
kaxil pushed a commit that referenced this pull request Sep 16, 2025
@jedcunningham@kaxil
Reduce default API server workers to 1 (#55707)
083f6e2
Change the default number of API server workers from 4 to 1 and add
guidance to deploy multiple API servers for scaling instead of
increasing workers per server.
With FastAPI, sync code runs in an external thread pool, making
multiple workers within a single api server less necessary than it was in
our flask days. And with uvicorns new spawn behavior instead of fork,
it means no shared copy-on-write memory between workers, so it's better
to scale horizontally now.
(cherry picked from commit 87fc469)
suman-himanshu pushed a commit to suman-himanshu/airflow that referenced this pull request Sep 17, 2025
@jedcunningham@suman-himanshu
Reduce default API server workers to 1 (apache#55707)
44b8e2f
Change the default number of API server workers from 4 to 1 and add
guidance to deploy multiple API servers for scaling instead of
increasing workers per server.
With FastAPI, sync code runs in an external thread pool, making
multiple workers within a single api server less necessary than it was in
our flask days. And with uvicorns new spawn behavior instead of fork,
it means no shared copy-on-write memory between workers, so it's better
to scale horizontally now.
dstandish pushed a commit to astronomer/airflow that referenced this pull request Sep 19, 2025
@jedcunningham
Reduce default API server workers to 1 (apache#55707)
5e04998
Change the default number of API server workers from 4 to 1 and add
guidance to deploy multiple API servers for scaling instead of
increasing workers per server.
With FastAPI, sync code runs in an external thread pool, making
multiple workers within a single api server less necessary than it was in
our flask days. And with uvicorns new spawn behavior instead of fork,
it means no shared copy-on-write memory between workers, so it's better
to scale horizontally now.
(cherry picked from commit 87fc469)
@r-richmondr-richmond mentioned this pull request Oct 26, 2025
Merged
@vlievenvlieven mentioned this pull request Nov 3, 2025
Merged
@potiukpotiuk mentioned this pull request Nov 8, 2025
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@kaxilkaxilkaxil approved these changes
@pierrejeambrunpierrejeambrunpierrejeambrun approved these changes
@vatsrahul1001vatsrahul1001vatsrahul1001 approved these changes
@vincbeckvincbeckvincbeck approved these changes

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Child process dies while api-server is hosted with docker

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