Add performance optimization and troubleshooting docs#2521
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Add three new pages to the optimize_performance section: - optimize_rendering: Covers DAG parsing performance with recommendations for LoadMode selection, reducing DAG granularity via selectors and TestBehavior, and skipping stale sources. - optimize_execution: Covers DAG run performance with guidance on execution mode selection (WATCHER recommended), dbt installation, pre-installing dependencies, profiles.yml usage, worker node sizing ratios per execution mode, and memory profiling. - troubleshooting: Covers diagnosing performance issues including Cosmos parse time logs, Airflow DAG processor configuration (with Airflow 2 and 3 settings), missing DAGs, and OOM errors. Each page leads with the recommended approach and links to existing detailed documentation rather than re-explaining concepts. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Pull request overview
Adds a new Optimize Performance docs section focused on helping Cosmos users diagnose and improve performance in two areas: DAG parsing (rendering) and task execution. It introduces dedicated pages for parsing optimization, execution optimization, and performance troubleshooting, and wires them into the section index.
Changes:
- Add new docs pages for optimizing DAG parsing, optimizing task execution, and performance troubleshooting.
- Update the Optimize Performance landing page to link to the new content and related existing guides (memory optimization, caching, invocation mode).
Reviewed changes
Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.
| File | Description |
|---|---|
| docs/optimize_performance/index.rst | Reworks the landing page and adds new pages to the toctree. |
| docs/optimize_performance/optimize_rendering.rst | New guidance on reducing DAG parse time (LoadMode, DAG granularity, sources). |
| docs/optimize_performance/optimize_execution.rst | New guidance on speeding up DAG runs (execution modes, deps, profiles, sizing, debug). |
| docs/optimize_performance/troubleshooting.rst | New troubleshooting playbook for parse-time, missing DAGs, and OOM diagnosis/mitigation. |
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tatiana
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It looks great, @pankajkoti , thanks a lot for putting this together!
I left minor feedback in line
- Expand "OOM" to "Out of Memory (OOM)" in index - Remove remote path suggestion from optimize_rendering since object store transfers add latency - Add experimental note for ExecutionMode.WATCHER - Clarify DBT_RUNNER is auto-selected when dbt is available, not unconditionally the default Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Apr 7, 2026
1.14.0 (2026-04-07) --------------------- Breaking Changes * Drop support for Airflow versions earlier than **2.9** by @jedcunningham in #2288 * Fix inclusion of package models and selection/exclusion behavior by @pankajkoti in #2357 * ``ExecutionMode.WATCHER``: The per-node ``*_status`` XCom value is now a dict (``{"status": "<status>", "outlet_uris": [...]}``) instead of a plain string. Any custom code that reads these internal XCom keys directly will need to be updated by @pankajkoti in #2507 Features * Add cluster policy support for ``ExecutionMode.WATCHER`` sensor retries by @astro-anand in #2293 * Add debug mode to track memory utilization by @tatiana in #2327 * Add FQN selection support for ``LoadMode.DBT_MANIFEST`` by @pankajastro in #2375 * Introduce interceptors for Cosmos tasks by @tatiana in #2419 * Add config to allow disabling dag versioning by @pankajkoti in #2470 * Implement TaskGroups by models folder by @maximilianoarcieri and @tatiana in #1566, #2469, and #2420 * feat: implement DbtTestWatcherOperator by @michal-mrazek in #2447 * Add source freshness aware execution for ``ExecutionMode.WATCHER`` by @pankajastro and @tatiana in #2467 * Note: Like ``ExecutionMode.WATCHER``, this feature is experimental and its interface and implementation can change in the future. * Add Airflow 3.2 support by @pankajastro and @pankajkoti in #2472 Enhancements * Add watcher mode support for dbt test node states by @michal-mrazek in #2318 * Rename watcher-mode sensor retry queue and reuse it for producer tasks by @pankajastro in #2331 * Fix leaked semaphore warnings in Airflow 3 by resetting dbt adapters by @pankajkoti in #2335 * Improve dbt Fusion support and related tests by @tatiana in #2356 * Default Snowflake profile mappings to four threads by @tatiana in #2374 * Attempt to remove Pydantic as a dependency by @tatiana in #2377 * Log dbt-core and adapter versions in watcher consumer tasks by @pankajastro in #2412 * Log model errors in watcher consumer on dbt node failure by @pankajastro in #2431 * Reduce XCom read/write for tracking node state and errors in ConsumerWatcher task by @pankajastro in #2471 * Remove duplicate debug log in watcher subprocess path by @tatiana in #2494 * Simplify and unify WATCHER implementation regardless of InvocationMode by @tatiana in #2498 * Switch to lazy imports in cosmos/__init__.py by @pankajkoti in #2531 Bug Fixes * Handle invalid YAML errors with ``LoadMode.DBT_MANIFEST`` and ``RenderConfig.selector`` by @YourRoyalLinus in #2316 * Populate ``compiled_sql`` for ``InvocationMode.SUBPROCESS`` in ``ExecutionMode.WATCHER`` by @pankajkoti in #2319 * Fix select/exclude type mismatch by @tatiana in #2364 * Set ``emit_datasets=False`` for ``DbtTest*`` operators by @pankajastro in #2365 * Set correct queue priority for watcher producer tasks by @pankajastro in #2372 * Preserve ``extra_context`` for watcher consumer task instances by @pankajkoti in #2381 * Respect ``deferrable=False`` from ``operator_args`` on watcher consumer sensors by @pankajkoti in #2384 * Fix watcher queue precedence and add documentation by @pankajastro in #2391 * Do not set ``compiled_sql`` on ``ExecutionMode.WATCHER`` producers by @pankajkoti in #2440 * Remove const attribute for ``__cosmos_telemetry_metadata__`` dag param by @pankajkoti in #2466 * Remove timeout override from Cosmos watcher sensors by @tatiana and @claude in #2478 * Remove forced ``retries=0`` from watcher producer operators by @tatiana in #2479 * RFC: Add patch for newer versions of amazon provider when running dbt on EKS by @aoelvp94 in #2481 * Fix ``cosmos_debug_max_memory_mb`` XCom not pushed in Watcher sensor tasks by @tatiana in #2503 * Fix ``TestBehavior.NONE`` and ``TestBehavior.AFTER_ALL`` exclude ignored with selectors in ``ExecutionMode.WATCHER`` by @pankajkoti in #2511 * Move dataset emission for ``ExecutionMode.WATCHER`` from producer to consumer sensors by @pankajkoti in #2507 Docs * Document cluster policy configuration for ``ExecutionMode.WATCHER`` sensor tasks by @pankajastro in #2315 * Remove outdated docs for the dbt docs plugin with Airflow 3 by @pankajastro in #2353 * Make Watcher DBT Execution Queue heading clickable by @pankajastro in #2354 * Update ``ExecutionMode.WATCHER`` documentation regarding test node implementation by @jroachgolf84 in #2355 * Fix ``pre_dbt_fusion`` configuration rendering by @pankajastro in #2369 * Add documentation for including/excluding nodes based on FQN by @pankajastro in #2371 * Update watcher execution mode documentation by @tatiana in #2380 * Add documentation for ``DbtSeedLocalOperator`` by @jroachgolf84 in #2383 * Fix miscellaneous Sphinx warnings by @pankajastro in #2395 * Improve contributing documentation by @lzdanski in #2397 * Add **Get Started in 5 Minutes** guide by @lzdanski in #2398 * Add Sphinx redirects package for documentation redirects by @lzdanski in #2407 * Restructure **Getting Started** and **Guides** sections by @lzdanski in #2418 * Add open-source quickstart by @lzdanski in #2439 * Fix documentation redirects by @lzdanski in #2442 * Restructure and refactor reference documentation by @lzdanski in #2443 * Add execution modes decision documentation by @lzdanski in #2444 * Add **Core Concepts** page to Getting Started by @lzdanski in #2448 * Add guide: *How Cosmos Works* by @lzdanski in #2449 * Update **Getting Started** overview and index pages by @lzdanski in #2452 * Add guide: *How Cosmos Runs dbt* by @lzdanski in #2453 * Fix miscellaneous documentation links by @lzdanski in #2454 * Add Mermaid diagrams and execution mode diagrams by @lzdanski and @tatiana in #2459 * Add documentation for memory optimization options by @pankajastro in #2340 * Fix typo in watcher execution mode docs by @evanvolgas in #2485 * Fix minor documentation issues by @evanvolgas in #2489 * Add troubleshooting note for dbt debug logs in ExecutionMode.WATCHER by @tatiana in #2491 * docs: unify RST header styles across documentation by @jigangz in #2473 * docs: fix env var for rich logging by @vricciardulli in #2514 * docs: update dbt project path example for Airflow 3 Astro compatibility by @yeoreums in #2512 * Document missing Cosmos Airflow config settings in cosmos-conf.rst by @tatiana in #2515 * Split security-privacy policy doc and add dependency cooldown by @pankajkoti in #2519 * Add performance optimization and troubleshooting docs by @pankajkoti in #2521 * Update copyright year to 2026 by @tayloramurphy in #2527 * docs: Updating "Project Policies" to "Policies" in menu bar by @jroachgolf84 in #2526 Others * Fix tests after removing support for Airflow versions earlier than 2.9 by @tatiana in #2321 * Enable listener tests for Airflow 3.1 by @pankajastro in #2348 * Accept ``int`` or ``float`` for ``cosmos_debug_max_memory_mb`` in integration tests by @pankajkoti in #2352 * Update ``CODEOWNERS`` to prioritize ``oss-integrations`` by @tatiana in #2359 * Fix automatic reviewer assignment in GitHub by @tatiana and @phanikumv in #2360 * Improve PyPI tagging by @tatiana in #2363 * Add integration tests for dbt Fusion and ``ExecutionMode.WATCHER`` by @tatiana in #2373 * Fix Zizmor check by @tatiana in #2376 * Remove ``methodtools`` dependency by @tatiana in #2378 * Improve comments on #2389 by @evanvolgas in #2394 * Refactor ``load_from_dbt_manifest`` to reduce code complexity by @pankajkoti in #2399 * Refactor ``_handle_no_precursors_or_descendants`` to reduce complexity by @pankajkoti in #2400 * Improve issue templates by @tatiana in #2401 * Avoid running tests when only docs change by @tatiana in #2402 * Add ``no-reload`` target for serving docs locally by @pankajkoti in #2405 * Fix test hash checks on macOS by @tatiana in #2406 * Attempt deterministic dbt project copy in test fixtures by @pankajkoti in #2409 * Pin ``virtualenv <21`` due to hatch incompatibility in CI by @pankajkoti in #2410 * Revert virtualenv pin for hatch installation in CI by @pankajkoti in #2426 * Add version comments for commit SHA pinned GitHub Actions by @pankajkoti in #2436 * Fix ``hatch run docs:build`` issues by @tatiana in #2437 * Minor code improvements by @dnskr in #2446 * Pre-commit autoupdate by @pre-commit-ci in #2367, #2396, #2422, #2451, #2468, #2495, and #2516 * Add file to support Claude understanding the Cosmos repository by @tatiana in #2458 * Dependency updates by @dependabot in #2368, #2425, #2435, #2465, #2475, #2504, #2518, and #2528 * Isolate Scarf telemetry integration test into its own CI job by @pankajkoti and @claude in #2477 * ci: upgrade Airflow version to 3.1 in MyPy type-check job by @yeoreums in #2506 * Add commit message guidelines to CLAUDE.md by @pankajkoti in #2509 * Extend skipping tests in CI for more non-code file changes by @pankajkoti in #2510 * Add Dependabot pre-commit support with 7-day cooldown by @pankajkoti in #2517 * Enforce zero warnings policy for documentation by @dnskr in #2513 Co-authored-by: Pankaj Koti <pankajkoti699@gmail.com> Co-authored-by: Tatiana Al-Chueyr <tatiana.alchueyr@gmail.com> --------- Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> Co-authored-by: Pankaj Koti <pankajkoti699@gmail.com> Co-authored-by: Tatiana Al-Chueyr <tatiana.alchueyr@gmail.com>
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Add three new pages to the optimize_performance section:
optimize_rendering: Covers DAG parsing performance with recommendations for LoadMode selection, reducing DAG granularity via selectors and TestBehavior, and skipping stale sources.
optimize_execution: Covers DAG run performance with guidance on execution mode selection (WATCHER recommended), dbt installation, pre-installing dependencies, profiles.yml usage, worker node sizing ratios per execution mode, and memory profiling.
troubleshooting: Covers diagnosing performance issues, including Cosmos parse time logs, Airflow DAG processor configuration (with Airflow 2 and 3 settings), missing DAGs, and OOM errors.
Each page leads with the recommended approach and links to existing detailed documentation rather than re-explaining concepts.
related: #2445