SObjectType.getDescribe() and SObjectField.getDescribe() increase Apex CPU consumption in API version 44+
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SObjectType.getDescribe() and SObjectField.getDescribe() increase Apex CPU consumption in API version 44+

Apex , Winter 19

Last updated 20 days ago ·Reference W-6105723 ·Reported By 191 users

In Review

Summary
SObjectType.getDescribe() and SObjectField.getDescribe() consume more Apex CPU time if API version is 44.0 or above.

Repro
1) In Workbench (https://workbench.developerforce.com), set the API version to 43.0, and run an the following Apex code in an anonymous block:

Map<String, Schema.SObjectType> globalDescribe = Schema.getGlobalDescribe();
for(Schema.SObjectType objectType : globalDescribe.values()) {
Schema.DescribeSObjectResult objDescribe = objectType.getDescribe();
for(Schema.SObjectField fieldType : objDescribe.fields.getMap().values()) {
Schema.DescribeFieldResult fieldDescribe = fieldType.getDescribe();
}
}
System.debug('CPU Time: ' + Limits.getCpuTime());
System.debug('Number of Entities: ' + globalDescribe.size());

You'll see an output similar to the one shown below:

|USER_DEBUG|[8]|DEBUG|CPU Time: 2559
|USER_DEBUG|[9]|DEBUG|Number of Entities: 548

2) Then, change the API version to 44.0, and run the code again. You'll see it consumes about 5 times more Apex CPU time in 44.0 even though the number of entities doesn't increase substantially.

|USER_DEBUG|[8]|DEBUG|CPU Time: 12351
|USER_DEBUG|[9]|DEBUG|Number of Entities: 558

Workaround
Change the affected Apex class' API version to 43.0 or below.

Updates
Ongoing performance review by R&D has indicated that there is still sub-optimal performance on describe calls in newer API versions. As a result this known issue is being re-opened and related to a new work item (W-6105723) reflecting more optimizations in this area. The initial fix remains in place and did improve performance, but did not fully resolve the issue.


--- 10/3/2019 ---
An improvement that allows deferring loading of describe attributes until first use instead of calculating on construction is included in Spring '20. This avoid overhead associated with pre-calculating attributes that may go unused and has shown substantial improvement in real-world use cases, particularly with complex customizations to the org schema. This is available via a new method overload on Schema.SObjectField.getDescribe() that allows specifying deferred vs full loading of describe details.

A critical update that is also included in Spring '20, "Use Improved Schema Caching" activates internal bug fixes and optimizations to the schema definition caching layer of the platform, and when enabled makes deferred loading the default behavior.

In other words, you can update your code to force the optimization regardless of the critical update's status (recommended for ISV development), or activate the critical update to opt-in to this change without code updates (recommended for admins of specific orgs).

Reported By (191)

Harsh Chaturvedi Chris Feldhacker Pritipadma Behera Marco Colombo Daniel Imamura Srihari Reddy Obul Reddy Vivek Vutukuri Jay McDoniel Aaron Huynh Fred Wade Alan Wojciechowski Bryan Leaman David Leinweber August Miller Rudy Ornelas Shoree Keislar Ben Gibbs David Kopel Niral Pokal Kelvin Lam Michael Yocca Osize Omoluabi Rajiv Mohanty Starley Flynn Rahul Das Chris Bunkers Jeferson Chaves Thomas Minney Tim Sneed Chris Sangrey Lyn Douglas Karen Guaspari Hayden Mcleod Hrvoje Prgeša Simon Maskell Adam Moreno Kameshwar Singh Emily Griffin Michael Eldredge Paritosh Sharma Natalya Murphy Tim Nee Vinay Vijay Pawan Kumar Aileen Wyer Eulogio Gallo Saurabh Kumar Jacob Blair Kalie Robins Betsy Hull Erin Durange Phil Ryan Desmond Li Bill Surgent Heidi Hopkins Niall Geraghty Jose Maria Lozano Deon Tredoux Autumn Young Matthew Sippel Shareen Mullen Andre Mink Ahmed Sohail Emily Tam Patty Ryder Mathieu Perrin David Hill Divya Kalyanasundaram Fergus Donnellan Chameen Battegoda Zakaria Aoujil Ann Marie Woelfel Ramón Muñoz Andriy Vesolovskyy Jeroen Burgers Nick Pasquarosa Steve Mills Chris Minotti Emily Klingelhutz Ron Hess Nir Sharon JoAnn Vormschlag-Eckhoff Kestryl Lowrey Ian Sidle 直樹 明石 Jerry Reid Shawn Hepker Greg Howell Tim May Ketan Baluja Victor Hanson Jeff McKinnis Mario Lukica Bojan Zunko Brent Gossett Katelyn Montigney Janise Dismuke Matthias Greier Marty Kopka Siddharth Mathur Matthew Anderson 奏 山本 Tim Johnson Matt Behr Zainab Shikari Arun Chockalingam Jon Scharff James Melville Konstantinos Vorilas David Esposito Shankar Dupade Daniel Appleman Reynald Ocampo Daniel Rudman Leslie Linard Tuoyo Omadeli Sean Singer Hiroyuki Sawano Kevin Jones Christian Croce Daniel Wright Jesús González System Administrator Matthew Taylor Pedro Vallesquino Jeffrey Watkins Alberto Contreras Tamas Faludi Chris Howard Victor Garrido Matas Alex Miller Alejandro Molina Salazar Eeva Ilama Aníbal García García Paul Allen Rafa Torres Alvaro Martinez Campos Agustina Garcia System Administrator Tom Corbett Martyn Ellison Daniel Butler-Taverner Manuel Moya Paul Hardaker Paul Lawrence James Woodward Alberto David Fernández Stephen Willcock Philip Rowe José Andrés Vilchez Rocio Varo Angel Luis Pinar Valli Babu Barbara Pai Lina Tsin Daniel Ballinger Carl Chen Thomas Tang Takahiro Kawabata 晃範 小野 伸也 羽田 anderson li yang yang Liang Cherry Brian Fear Leo Li Justin LaMont Eric Kintzer Jeff Hube Anne Shields Sean Singer James Browne Oliver Deighton Roberto Tomasoni Andrea Parimbelli Daniel Exposito Javier Labrat Dave Casper Luke Cotter Geoffrey Swift System Administrator Alex Lenthall Matthew Morris Javier Coca James Hadfield Jose Luis Martinez Michael Chadwick Sergio Salmerón Valerio Sevilla Bethany Kohler Jon Wilson

Is it Fixed?

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