Skip to content

[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704)#71821

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
jason810496 merged 1 commit into from
Aug 19, 2026
Merged

[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704) #71821

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 1 addition & 0 deletions airflow-core/newsfragments/71704.bugfix.rst
View file
Open in desktop
Original file line numberDiff line numberDiff line change
@@ -0,0 +1 @@
The scheduler's Dag cache is now a bounded LRU of 512 versions, so scheduler memory no longer grows with every Dag version the process has ever seen.
14 changes: 13 additions & 1 deletion airflow-core/src/airflow/jobs/scheduler_job_runner.py
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -154,6 +154,18 @@
TASK_STUCK_IN_QUEUED_RESCHEDULE_EVENT = "stuck in queued reschedule"
""":meta private:"""

SCHEDULER_DAG_CACHE_SIZE = 512
"""
Max deserialized Dag versions the scheduler keeps in memory.

The scheduler reaches its DagBag through the Dag version of each active Dag run, so an
unbounded cache retains every version the process has ever seen and grows for the life of
the process. Sized to sit above the versions-with-runs-in-flight working set of a typical
deployment, so eviction costs a re-fetch only where that working set is genuinely larger.

:meta private:
"""

# Per-tick cap on pending AssetPartitionDagRun rows the scheduler evaluates.
# Bounds the per-tick transaction so executor heartbeats and regular scheduling
# aren't starved; remaining APDRs drain across subsequent ticks.
Expand DownExpand Up@@ -348,7 +360,7 @@ def __init__(
if log:
self._log = log

self.scheduler_dag_bag = DBDagBag(load_op_links=False)
self.scheduler_dag_bag = DBDagBag(load_op_links=False, cache_size=SCHEDULER_DAG_CACHE_SIZE)

# Set of (dag_id, asset_name, asset_uri) tuples for trigger policies that
# are permanently unreachable for the rollup window's cardinality — the
Expand Down
11 changes: 10 additions & 1 deletion airflow-core/tests/unit/jobs/test_scheduler_job.py
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -57,7 +57,7 @@
from airflow.executors.executor_utils import ExecutorName
from airflow.executors.local_executor import LocalExecutor
from airflow.jobs.job import Job, run_job
from airflow.jobs.scheduler_job_runner import SchedulerJobRunner
from airflow.jobs.scheduler_job_runner import SCHEDULER_DAG_CACHE_SIZE, SchedulerJobRunner
from airflow.models.asset import (
AssetActive,
AssetAliasModel,
Expand DownExpand Up@@ -410,6 +410,15 @@ def test_executor_loaded_in_scheduler_job(self, mock_init_executors, mock_defaul
assert scheduler_job.executor == mock_local_executor
assert scheduler_job.executors == [mock_local_executor]

def test_scheduler_dag_bag_is_bounded(self):
"""The scheduler's Dag cache must evict, or it retains every version it has ever seen."""
from cachetools import LRUCache

job_runner = SchedulerJobRunner(Job())

assert isinstance(job_runner.scheduler_dag_bag._dags, LRUCache)
assert job_runner.scheduler_dag_bag._dags.maxsize == SCHEDULER_DAG_CACHE_SIZE

@pytest.mark.parametrize(
"heartrate",
[10, 5],
Expand Down
Loading
, 'i'); if (__m === '*' || __re.test(location.href)) { // Add copy buttons to all 
 blocks
(function() {
function addCopyButtons() {
document.querySelectorAll('pre code').forEach(function(codeBlock) {
if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;
codeBlock.parentElement.setAttribute('data-copy-added', 'true');
var btn = document.createElement('button');
btn.textContent = 'Copy';
btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';
btn.onmouseover = function() { this.style.opacity = '1'; };
btn.onmouseout = function() { this.style.opacity = '0.7'; };
btn.onclick = function() {
navigator.clipboard.writeText(codeBlock.textContent).then(function() {
btn.textContent = 'Copied!';
setTimeout(function() { btn.textContent = 'Copy'; }, 1500);
});
};
codeBlock.parentElement.style.position = 'relative';
codeBlock.parentElement.appendChild(btn);
});
}
addCopyButtons();
// Re-run on dynamic content
var observer = new MutationObserver(addCopyButtons);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '
[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704) by github-actions[bot] · Pull Request #71821 · apache/airflow · GitHub
Skip to content
[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704)#71821

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

 Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and
privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
Sign in
to your account

 Merged

jason810496
merged 1 commit into

from

Aug 19, 2026
 Merged


[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704)
#71821
Show file tree
Hide file tree
 Changes from all commits
Commits

Show all changes


1 commit


Select commit


File filter

Filter by extension
Filter by extension
Conversations

Failed to load comments. 
Loading
Jump to

Jump to file


Failed to load files. 
Loading
 Diff view

 Diff view


1 change: 1 addition & 0 deletions
airflow-core/newsfragments/71704.bugfix.rst

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1 @@
The scheduler's Dag cache is now a bounded LRU of 512 versions, so scheduler memory no longer grows with every Dag version the process has ever seen.

14 changes: 13 additions & 1 deletion
airflow-core/src/airflow/jobs/scheduler_job_runner.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -154,6 +154,18 @@
TASK_STUCK_IN_QUEUED_RESCHEDULE_EVENT = "stuck in queued reschedule"
""":meta private:"""

SCHEDULER_DAG_CACHE_SIZE = 512
"""
Max deserialized Dag versions the scheduler keeps in memory.

The scheduler reaches its DagBag through the Dag version of each active Dag run, so an
unbounded cache retains every version the process has ever seen and grows for the life of
the process. Sized to sit above the versions-with-runs-in-flight working set of a typical
deployment, so eviction costs a re-fetch only where that working set is genuinely larger.

:meta private:
"""

# Per-tick cap on pending AssetPartitionDagRun rows the scheduler evaluates.
# Bounds the per-tick transaction so executor heartbeats and regular scheduling
# aren't starved; remaining APDRs drain across subsequent ticks.
Expand DownExpand Up@@ -348,7 +360,7 @@ def __init__(
 if log:
 self._log = log

 self.scheduler_dag_bag = DBDagBag(load_op_links=False)
 self.scheduler_dag_bag = DBDagBag(load_op_links=False, cache_size=SCHEDULER_DAG_CACHE_SIZE)

 # Set of (dag_id, asset_name, asset_uri) tuples for trigger policies that
 # are permanently unreachable for the rollup window's cardinality — the
Expand Down

11 changes: 10 additions & 1 deletion
airflow-core/tests/unit/jobs/test_scheduler_job.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -57,7 +57,7 @@
from airflow.executors.executor_utils import ExecutorName
from airflow.executors.local_executor import LocalExecutor
from airflow.jobs.job import Job, run_job
from airflow.jobs.scheduler_job_runner import SchedulerJobRunner
from airflow.jobs.scheduler_job_runner import SCHEDULER_DAG_CACHE_SIZE, SchedulerJobRunner
from airflow.models.asset import (
 AssetActive,
 AssetAliasModel,
Expand DownExpand Up@@ -410,6 +410,15 @@ def test_executor_loaded_in_scheduler_job(self, mock_init_executors, mock_defaul
 assert scheduler_job.executor == mock_local_executor
 assert scheduler_job.executors == [mock_local_executor]

 def test_scheduler_dag_bag_is_bounded(self):
 """The scheduler's Dag cache must evict, or it retains every version it has ever seen."""
 from cachetools import LRUCache

 job_runner = SchedulerJobRunner(Job())

 assert isinstance(job_runner.scheduler_dag_bag._dags, LRUCache)
 assert job_runner.scheduler_dag_bag._dags.maxsize == SCHEDULER_DAG_CACHE_SIZE

 @pytest.mark.parametrize(
 "heartrate",
 [10, 5],
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Force GitHub README to respect dark mode
(function() {
var style = document.createElement('style');
style.textContent = '
.markdown-body {
color-scheme: dark light;
}
.markdown-body pre { background: #161b22 !important; }
.markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }
.markdown-body table th, .markdown-body table td { border-color: #30363d !important; }
.markdown-body img { background: #0d1117; }
.markdown-body blockquote { border-left-color: #8b949e; }
.markdown-body hr { border-color: #30363d; }
';
document.head.appendChild(style);
})();
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704) by github-actions[bot] · Pull Request #71821 · apache/airflow · GitHub
Skip to content
[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704)#71821

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

 Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and
privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
Sign in
to your account

 Merged

jason810496
merged 1 commit into

from

Aug 19, 2026
 Merged


[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704)
#71821
Show file tree
Hide file tree
 Changes from all commits
Commits

Show all changes


1 commit


Select commit


File filter

Filter by extension
Filter by extension
Conversations

Failed to load comments. 
Loading
Jump to

Jump to file


Failed to load files. 
Loading
 Diff view

 Diff view


1 change: 1 addition & 0 deletions
airflow-core/newsfragments/71704.bugfix.rst

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1 @@
The scheduler's Dag cache is now a bounded LRU of 512 versions, so scheduler memory no longer grows with every Dag version the process has ever seen.

14 changes: 13 additions & 1 deletion
airflow-core/src/airflow/jobs/scheduler_job_runner.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -154,6 +154,18 @@
TASK_STUCK_IN_QUEUED_RESCHEDULE_EVENT = "stuck in queued reschedule"
""":meta private:"""

SCHEDULER_DAG_CACHE_SIZE = 512
"""
Max deserialized Dag versions the scheduler keeps in memory.

The scheduler reaches its DagBag through the Dag version of each active Dag run, so an
unbounded cache retains every version the process has ever seen and grows for the life of
the process. Sized to sit above the versions-with-runs-in-flight working set of a typical
deployment, so eviction costs a re-fetch only where that working set is genuinely larger.

:meta private:
"""

# Per-tick cap on pending AssetPartitionDagRun rows the scheduler evaluates.
# Bounds the per-tick transaction so executor heartbeats and regular scheduling
# aren't starved; remaining APDRs drain across subsequent ticks.
Expand DownExpand Up@@ -348,7 +360,7 @@ def __init__(
 if log:
 self._log = log

 self.scheduler_dag_bag = DBDagBag(load_op_links=False)
 self.scheduler_dag_bag = DBDagBag(load_op_links=False, cache_size=SCHEDULER_DAG_CACHE_SIZE)

 # Set of (dag_id, asset_name, asset_uri) tuples for trigger policies that
 # are permanently unreachable for the rollup window's cardinality — the
Expand Down

11 changes: 10 additions & 1 deletion
airflow-core/tests/unit/jobs/test_scheduler_job.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -57,7 +57,7 @@
from airflow.executors.executor_utils import ExecutorName
from airflow.executors.local_executor import LocalExecutor
from airflow.jobs.job import Job, run_job
from airflow.jobs.scheduler_job_runner import SchedulerJobRunner
from airflow.jobs.scheduler_job_runner import SCHEDULER_DAG_CACHE_SIZE, SchedulerJobRunner
from airflow.models.asset import (
 AssetActive,
 AssetAliasModel,
Expand DownExpand Up@@ -410,6 +410,15 @@ def test_executor_loaded_in_scheduler_job(self, mock_init_executors, mock_defaul
 assert scheduler_job.executor == mock_local_executor
 assert scheduler_job.executors == [mock_local_executor]

 def test_scheduler_dag_bag_is_bounded(self):
 """The scheduler's Dag cache must evict, or it retains every version it has ever seen."""
 from cachetools import LRUCache

 job_runner = SchedulerJobRunner(Job())

 assert isinstance(job_runner.scheduler_dag_bag._dags, LRUCache)
 assert job_runner.scheduler_dag_bag._dags.maxsize == SCHEDULER_DAG_CACHE_SIZE

 @pytest.mark.parametrize(
 "heartrate",
 [10, 5],
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Highlight search terms from Google/DuckDuckGo/Bing referrer
(function() {
var ref = document.referrer;
var terms = [];
if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {
var url = new URL(ref);
var q = url.searchParams.get('q') || url.searchParams.get('p');
if (q) {
terms = q.split(/\s+/).filter(function(t) { return t.length > 2; });
}
}
if (terms.length === 0) return;
var style = document.createElement('style');
style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';
document.head.appendChild(style);
function highlight(node) {
if (node.nodeType === 3) { // text node
var text = node.textContent;
var found = false;
terms.forEach(function(term) {
var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\]\\]/g, '\\') + ')', '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('^' + ".*" + '
[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704) by github-actions[bot] · Pull Request #71821 · apache/airflow · GitHub
Skip to content
[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704)#71821

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

 Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and
privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
Sign in
to your account

 Merged

jason810496
merged 1 commit into

from

Aug 19, 2026
 Merged


[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704)
#71821
Show file tree
Hide file tree
 Changes from all commits
Commits

Show all changes


1 commit


Select commit


File filter

Filter by extension
Filter by extension
Conversations

Failed to load comments. 
Loading
Jump to

Jump to file


Failed to load files. 
Loading
 Diff view

 Diff view


1 change: 1 addition & 0 deletions
airflow-core/newsfragments/71704.bugfix.rst

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1 @@
The scheduler's Dag cache is now a bounded LRU of 512 versions, so scheduler memory no longer grows with every Dag version the process has ever seen.

14 changes: 13 additions & 1 deletion
airflow-core/src/airflow/jobs/scheduler_job_runner.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -154,6 +154,18 @@
TASK_STUCK_IN_QUEUED_RESCHEDULE_EVENT = "stuck in queued reschedule"
""":meta private:"""

SCHEDULER_DAG_CACHE_SIZE = 512
"""
Max deserialized Dag versions the scheduler keeps in memory.

The scheduler reaches its DagBag through the Dag version of each active Dag run, so an
unbounded cache retains every version the process has ever seen and grows for the life of
the process. Sized to sit above the versions-with-runs-in-flight working set of a typical
deployment, so eviction costs a re-fetch only where that working set is genuinely larger.

:meta private:
"""

# Per-tick cap on pending AssetPartitionDagRun rows the scheduler evaluates.
# Bounds the per-tick transaction so executor heartbeats and regular scheduling
# aren't starved; remaining APDRs drain across subsequent ticks.
Expand DownExpand Up@@ -348,7 +360,7 @@ def __init__(
 if log:
 self._log = log

 self.scheduler_dag_bag = DBDagBag(load_op_links=False)
 self.scheduler_dag_bag = DBDagBag(load_op_links=False, cache_size=SCHEDULER_DAG_CACHE_SIZE)

 # Set of (dag_id, asset_name, asset_uri) tuples for trigger policies that
 # are permanently unreachable for the rollup window's cardinality — the
Expand Down

11 changes: 10 additions & 1 deletion
airflow-core/tests/unit/jobs/test_scheduler_job.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -57,7 +57,7 @@
from airflow.executors.executor_utils import ExecutorName
from airflow.executors.local_executor import LocalExecutor
from airflow.jobs.job import Job, run_job
from airflow.jobs.scheduler_job_runner import SchedulerJobRunner
from airflow.jobs.scheduler_job_runner import SCHEDULER_DAG_CACHE_SIZE, SchedulerJobRunner
from airflow.models.asset import (
 AssetActive,
 AssetAliasModel,
Expand DownExpand Up@@ -410,6 +410,15 @@ def test_executor_loaded_in_scheduler_job(self, mock_init_executors, mock_defaul
 assert scheduler_job.executor == mock_local_executor
 assert scheduler_job.executors == [mock_local_executor]

 def test_scheduler_dag_bag_is_bounded(self):
 """The scheduler's Dag cache must evict, or it retains every version it has ever seen."""
 from cachetools import LRUCache

 job_runner = SchedulerJobRunner(Job())

 assert isinstance(job_runner.scheduler_dag_bag._dags, LRUCache)
 assert job_runner.scheduler_dag_bag._dags.maxsize == SCHEDULER_DAG_CACHE_SIZE

 @pytest.mark.parametrize(
 "heartrate",
 [10, 5],
Expand Down
Loading

, '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" + '
[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704) by github-actions[bot] · Pull Request #71821 · apache/airflow · GitHub
Skip to content
[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704)#71821

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

 Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and
privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
Sign in
to your account

 Merged

jason810496
merged 1 commit into

from

Aug 19, 2026
 Merged


[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704)
#71821
Show file tree
Hide file tree
 Changes from all commits
Commits

Show all changes


1 commit


Select commit


File filter

Filter by extension
Filter by extension
Conversations

Failed to load comments. 
Loading
Jump to

Jump to file


Failed to load files. 
Loading
 Diff view

 Diff view


1 change: 1 addition & 0 deletions
airflow-core/newsfragments/71704.bugfix.rst

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1 @@
The scheduler's Dag cache is now a bounded LRU of 512 versions, so scheduler memory no longer grows with every Dag version the process has ever seen.

14 changes: 13 additions & 1 deletion
airflow-core/src/airflow/jobs/scheduler_job_runner.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -154,6 +154,18 @@
TASK_STUCK_IN_QUEUED_RESCHEDULE_EVENT = "stuck in queued reschedule"
""":meta private:"""

SCHEDULER_DAG_CACHE_SIZE = 512
"""
Max deserialized Dag versions the scheduler keeps in memory.

The scheduler reaches its DagBag through the Dag version of each active Dag run, so an
unbounded cache retains every version the process has ever seen and grows for the life of
the process. Sized to sit above the versions-with-runs-in-flight working set of a typical
deployment, so eviction costs a re-fetch only where that working set is genuinely larger.

:meta private:
"""

# Per-tick cap on pending AssetPartitionDagRun rows the scheduler evaluates.
# Bounds the per-tick transaction so executor heartbeats and regular scheduling
# aren't starved; remaining APDRs drain across subsequent ticks.
Expand DownExpand Up@@ -348,7 +360,7 @@ def __init__(
 if log:
 self._log = log

 self.scheduler_dag_bag = DBDagBag(load_op_links=False)
 self.scheduler_dag_bag = DBDagBag(load_op_links=False, cache_size=SCHEDULER_DAG_CACHE_SIZE)

 # Set of (dag_id, asset_name, asset_uri) tuples for trigger policies that
 # are permanently unreachable for the rollup window's cardinality — the
Expand Down

11 changes: 10 additions & 1 deletion
airflow-core/tests/unit/jobs/test_scheduler_job.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -57,7 +57,7 @@
from airflow.executors.executor_utils import ExecutorName
from airflow.executors.local_executor import LocalExecutor
from airflow.jobs.job import Job, run_job
from airflow.jobs.scheduler_job_runner import SchedulerJobRunner
from airflow.jobs.scheduler_job_runner import SCHEDULER_DAG_CACHE_SIZE, SchedulerJobRunner
from airflow.models.asset import (
 AssetActive,
 AssetAliasModel,
Expand DownExpand Up@@ -410,6 +410,15 @@ def test_executor_loaded_in_scheduler_job(self, mock_init_executors, mock_defaul
 assert scheduler_job.executor == mock_local_executor
 assert scheduler_job.executors == [mock_local_executor]

 def test_scheduler_dag_bag_is_bounded(self):
 """The scheduler's Dag cache must evict, or it retains every version it has ever seen."""
 from cachetools import LRUCache

 job_runner = SchedulerJobRunner(Job())

 assert isinstance(job_runner.scheduler_dag_bag._dags, LRUCache)
 assert job_runner.scheduler_dag_bag._dags.maxsize == SCHEDULER_DAG_CACHE_SIZE

 @pytest.mark.parametrize(
 "heartrate",
 [10, 5],
Expand Down
Loading

, '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('^' + ".*" + '
[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704) by github-actions[bot] · Pull Request #71821 · apache/airflow · GitHub
Skip to content
[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704)#71821

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

 Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and
privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
Sign in
to your account

 Merged

jason810496
merged 1 commit into

from

Aug 19, 2026
 Merged


[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704)
#71821
Show file tree
Hide file tree
 Changes from all commits
Commits

Show all changes


1 commit


Select commit


File filter

Filter by extension
Filter by extension
Conversations

Failed to load comments. 
Loading
Jump to

Jump to file


Failed to load files. 
Loading
 Diff view

 Diff view


1 change: 1 addition & 0 deletions
airflow-core/newsfragments/71704.bugfix.rst

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1 @@
The scheduler's Dag cache is now a bounded LRU of 512 versions, so scheduler memory no longer grows with every Dag version the process has ever seen.

14 changes: 13 additions & 1 deletion
airflow-core/src/airflow/jobs/scheduler_job_runner.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -154,6 +154,18 @@
TASK_STUCK_IN_QUEUED_RESCHEDULE_EVENT = "stuck in queued reschedule"
""":meta private:"""

SCHEDULER_DAG_CACHE_SIZE = 512
"""
Max deserialized Dag versions the scheduler keeps in memory.

The scheduler reaches its DagBag through the Dag version of each active Dag run, so an
unbounded cache retains every version the process has ever seen and grows for the life of
the process. Sized to sit above the versions-with-runs-in-flight working set of a typical
deployment, so eviction costs a re-fetch only where that working set is genuinely larger.

:meta private:
"""

# Per-tick cap on pending AssetPartitionDagRun rows the scheduler evaluates.
# Bounds the per-tick transaction so executor heartbeats and regular scheduling
# aren't starved; remaining APDRs drain across subsequent ticks.
Expand DownExpand Up@@ -348,7 +360,7 @@ def __init__(
 if log:
 self._log = log

 self.scheduler_dag_bag = DBDagBag(load_op_links=False)
 self.scheduler_dag_bag = DBDagBag(load_op_links=False, cache_size=SCHEDULER_DAG_CACHE_SIZE)

 # Set of (dag_id, asset_name, asset_uri) tuples for trigger policies that
 # are permanently unreachable for the rollup window's cardinality — the
Expand Down

11 changes: 10 additions & 1 deletion
airflow-core/tests/unit/jobs/test_scheduler_job.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -57,7 +57,7 @@
from airflow.executors.executor_utils import ExecutorName
from airflow.executors.local_executor import LocalExecutor
from airflow.jobs.job import Job, run_job
from airflow.jobs.scheduler_job_runner import SchedulerJobRunner
from airflow.jobs.scheduler_job_runner import SCHEDULER_DAG_CACHE_SIZE, SchedulerJobRunner
from airflow.models.asset import (
 AssetActive,
 AssetAliasModel,
Expand DownExpand Up@@ -410,6 +410,15 @@ def test_executor_loaded_in_scheduler_job(self, mock_init_executors, mock_defaul
 assert scheduler_job.executor == mock_local_executor
 assert scheduler_job.executors == [mock_local_executor]

 def test_scheduler_dag_bag_is_bounded(self):
 """The scheduler's Dag cache must evict, or it retains every version it has ever seen."""
 from cachetools import LRUCache

 job_runner = SchedulerJobRunner(Job())

 assert isinstance(job_runner.scheduler_dag_bag._dags, LRUCache)
 assert job_runner.scheduler_dag_bag._dags.maxsize == SCHEDULER_DAG_CACHE_SIZE

 @pytest.mark.parametrize(
 "heartrate",
 [10, 5],
Expand Down
Loading

, '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); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704) by github-actions[bot] · Pull Request #71821 · apache/airflow · GitHub
Skip to content
[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704)#71821

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

 Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and
privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
Sign in
to your account

 Merged

jason810496
merged 1 commit into

from

Aug 19, 2026
 Merged


[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704)
#71821
Show file tree
Hide file tree
 Changes from all commits
Commits

Show all changes


1 commit


Select commit


File filter

Filter by extension
Filter by extension
Conversations

Failed to load comments. 
Loading
Jump to

Jump to file


Failed to load files. 
Loading
 Diff view

 Diff view


1 change: 1 addition & 0 deletions
airflow-core/newsfragments/71704.bugfix.rst

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1 @@
The scheduler's Dag cache is now a bounded LRU of 512 versions, so scheduler memory no longer grows with every Dag version the process has ever seen.

14 changes: 13 additions & 1 deletion
airflow-core/src/airflow/jobs/scheduler_job_runner.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -154,6 +154,18 @@
TASK_STUCK_IN_QUEUED_RESCHEDULE_EVENT = "stuck in queued reschedule"
""":meta private:"""

SCHEDULER_DAG_CACHE_SIZE = 512
"""
Max deserialized Dag versions the scheduler keeps in memory.

The scheduler reaches its DagBag through the Dag version of each active Dag run, so an
unbounded cache retains every version the process has ever seen and grows for the life of
the process. Sized to sit above the versions-with-runs-in-flight working set of a typical
deployment, so eviction costs a re-fetch only where that working set is genuinely larger.

:meta private:
"""

# Per-tick cap on pending AssetPartitionDagRun rows the scheduler evaluates.
# Bounds the per-tick transaction so executor heartbeats and regular scheduling
# aren't starved; remaining APDRs drain across subsequent ticks.
Expand DownExpand Up@@ -348,7 +360,7 @@ def __init__(
 if log:
 self._log = log

 self.scheduler_dag_bag = DBDagBag(load_op_links=False)
 self.scheduler_dag_bag = DBDagBag(load_op_links=False, cache_size=SCHEDULER_DAG_CACHE_SIZE)

 # Set of (dag_id, asset_name, asset_uri) tuples for trigger policies that
 # are permanently unreachable for the rollup window's cardinality — the
Expand Down

11 changes: 10 additions & 1 deletion
airflow-core/tests/unit/jobs/test_scheduler_job.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -57,7 +57,7 @@
from airflow.executors.executor_utils import ExecutorName
from airflow.executors.local_executor import LocalExecutor
from airflow.jobs.job import Job, run_job
from airflow.jobs.scheduler_job_runner import SchedulerJobRunner
from airflow.jobs.scheduler_job_runner import SCHEDULER_DAG_CACHE_SIZE, SchedulerJobRunner
from airflow.models.asset import (
 AssetActive,
 AssetAliasModel,
Expand DownExpand Up@@ -410,6 +410,15 @@ def test_executor_loaded_in_scheduler_job(self, mock_init_executors, mock_defaul
 assert scheduler_job.executor == mock_local_executor
 assert scheduler_job.executors == [mock_local_executor]

 def test_scheduler_dag_bag_is_bounded(self):
 """The scheduler's Dag cache must evict, or it retains every version it has ever seen."""
 from cachetools import LRUCache

 job_runner = SchedulerJobRunner(Job())

 assert isinstance(job_runner.scheduler_dag_bag._dags, LRUCache)
 assert job_runner.scheduler_dag_bag._dags.maxsize == SCHEDULER_DAG_CACHE_SIZE

 @pytest.mark.parametrize(
 "heartrate",
 [10, 5],
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Universal Dark Mode - works on any site
(function() {
var enabled = true;
function applyDarkMode() {
if (!enabled) return;
// Create style element if it doesn't exist
var style = document.getElementById('universal-dark-mode-style');
if (!style) {
style = document.createElement('style');
style.id = 'universal-dark-mode-style';
document.head.appendChild(style);
}
// Dark mode CSS - inverts colors but preserves images/video
style.textContent = '
/* Invert everything except media */
html {
filter: invert(1) hue-rotate(180deg) !important;
background: #1a1a2e !important;
}
/* Restore images, videos, iframes, canvas */
img, video, iframe, canvas, svg, picture, [style*="background-image"] {
filter: invert(1) hue-rotate(180deg) !important;
}
/* Preserve specific elements that should not be inverted */
.no-dark-mode, .no-dark-mode *,
[data-theme="light"], [data-theme="light"],
.ace_editor, .ace_editor *,
.CodeMirror, .CodeMirror *,
.monaco-editor, .monaco-editor *,
.markdown-body pre, .markdown-body pre *,
.highlight, .highlight *,
pre code, pre code * {
filter: none !important;
}
/* Fix common UI elements */
.modal, .popup, .dropdown-menu, .tooltip, .popover {
filter: invert(1) hue-rotate(180deg) !important;
background: #2d2d44 !important;
border-color: #444 !important;
}
/* Scrollbars */
::-webkit-scrollbar { background: #1a1a2e !important; }
::-webkit-scrollbar-thumb { background: #444 !important; }
::-webkit-scrollbar-thumb:hover { background: #555 !important; }
/* Selection */
::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
';
}
function removeDarkMode() {
var style = document.getElementById('universal-dark-mode-style');
if (style) style.remove();
}
// Toggle with Alt+Shift+D
document.addEventListener('keydown', function(e) {
if (e.altKey && e.shiftKey && e.key === 'D') {
e.preventDefault();
enabled = !enabled;
if (enabled) {
applyDarkMode();
console.log('[Universal Dark Mode] Enabled');
} else {
removeDarkMode();
console.log('[Universal Dark Mode] Disabled');
}
}
});
// Apply on load
applyDarkMode();
// Re-apply on dynamic content
var observer = new MutationObserver(function(mutations) {
if (enabled && !document.getElementById('universal-dark-mode-style')) {
applyDarkMode();
}
});
observer.observe(document.head, { childList: true });
console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');
})();
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();
[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704) by github-actions[bot] · Pull Request #71821 · apache/airflow · GitHub
Skip to content
[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704)#71821

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

 Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and
privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
Sign in
to your account

 Merged

jason810496
merged 1 commit into

from

Aug 19, 2026
 Merged


[v3-3-test] Bound the scheduler's deserialized Dag cache (#71704)
#71821
Show file tree
Hide file tree
 Changes from all commits
Commits

Show all changes


1 commit


Select commit


File filter

Filter by extension
Filter by extension
Conversations

Failed to load comments. 
Loading
Jump to

Jump to file


Failed to load files. 
Loading
 Diff view

 Diff view


1 change: 1 addition & 0 deletions
airflow-core/newsfragments/71704.bugfix.rst

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1 @@
The scheduler's Dag cache is now a bounded LRU of 512 versions, so scheduler memory no longer grows with every Dag version the process has ever seen.

14 changes: 13 additions & 1 deletion
airflow-core/src/airflow/jobs/scheduler_job_runner.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -154,6 +154,18 @@
TASK_STUCK_IN_QUEUED_RESCHEDULE_EVENT = "stuck in queued reschedule"
""":meta private:"""

SCHEDULER_DAG_CACHE_SIZE = 512
"""
Max deserialized Dag versions the scheduler keeps in memory.

The scheduler reaches its DagBag through the Dag version of each active Dag run, so an
unbounded cache retains every version the process has ever seen and grows for the life of
the process. Sized to sit above the versions-with-runs-in-flight working set of a typical
deployment, so eviction costs a re-fetch only where that working set is genuinely larger.

:meta private:
"""

# Per-tick cap on pending AssetPartitionDagRun rows the scheduler evaluates.
# Bounds the per-tick transaction so executor heartbeats and regular scheduling
# aren't starved; remaining APDRs drain across subsequent ticks.
Expand DownExpand Up@@ -348,7 +360,7 @@ def __init__(
 if log:
 self._log = log

 self.scheduler_dag_bag = DBDagBag(load_op_links=False)
 self.scheduler_dag_bag = DBDagBag(load_op_links=False, cache_size=SCHEDULER_DAG_CACHE_SIZE)

 # Set of (dag_id, asset_name, asset_uri) tuples for trigger policies that
 # are permanently unreachable for the rollup window's cardinality — the
Expand Down

11 changes: 10 additions & 1 deletion
airflow-core/tests/unit/jobs/test_scheduler_job.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -57,7 +57,7 @@
from airflow.executors.executor_utils import ExecutorName
from airflow.executors.local_executor import LocalExecutor
from airflow.jobs.job import Job, run_job
from airflow.jobs.scheduler_job_runner import SchedulerJobRunner
from airflow.jobs.scheduler_job_runner import SCHEDULER_DAG_CACHE_SIZE, SchedulerJobRunner
from airflow.models.asset import (
 AssetActive,
 AssetAliasModel,
Expand DownExpand Up@@ -410,6 +410,15 @@ def test_executor_loaded_in_scheduler_job(self, mock_init_executors, mock_defaul
 assert scheduler_job.executor == mock_local_executor
 assert scheduler_job.executors == [mock_local_executor]

 def test_scheduler_dag_bag_is_bounded(self):
 """The scheduler's Dag cache must evict, or it retains every version it has ever seen."""
 from cachetools import LRUCache

 job_runner = SchedulerJobRunner(Job())

 assert isinstance(job_runner.scheduler_dag_bag._dags, LRUCache)
 assert job_runner.scheduler_dag_bag._dags.maxsize == SCHEDULER_DAG_CACHE_SIZE

 @pytest.mark.parametrize(
 "heartrate",
 [10, 5],
Expand Down
Loading