Follow the evidence: Troubleshooting Performance Issues

Follow the evidence:
Troubleshooting performance issues
T.K. Horeis, salesforce.com, Cloud and Industry Architect
@TKHoreis

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forward-looking statements.

T.K. Horeis
Cloud and Industry Architect
@TKHoreis

Our customer, let’s call them Brand-X

Tip:
Don’t Rush
To
Judgement

%
9
>

>1
0%

They Were Simply Using Too Much Capacity
Tip:
Don’t Rush
To
Judgement

How Did We Know?
Tip:
it a
Subm To
Case er
i
rem t
P
ppor
Su

• Count
• Long-running
operations
• Total Runtime
• CPU time
• Db CPU time
• Buffer Gets

So We Recommended That They Needed To…
40% – 50%

▪ Reduce combined buffer gets and DB CPU by
20% - 25%

▪ Reduce combined runTime by
20%-25%

▪ Reduce combined App cpuTime by

Here’s What We Knew At The Time
• Capacity usage was proportionally LARGE
• The EU org will be merged into NA
• EU users would use NA business processes only
• Some EMEA users (Ireland) have already been moved over.

And this is
where our
investigation
begins…

Lots Of Evidence At The Scene Of The Crime

Lots Of Evidence At The Scene Of The Crime
RE

ST

S

AP
O

So Just What Are They Loading So Many Times?

•
•
•
•
•
•
•
•
•
•

/apex/qbdialer__sid 1814897
/apex/questionpage 6314
/apex/oppinformationrequest 5871
/apex/merchantaddys 5636
/apex/dnralert 5611
/apex/redemptionaddy 5503
/apex/account_geocoder 5080
/apex/pastdeals 4589
/apex/inlineoptions 3986
/apex/accountgoogleanalytics 3444

And When We Dig Further…

Where the median # of calls per day is ~1500.
Were those top 4 users REALLY making hundreds of
thousands of calls per day?

Not Exactly…
An old version of Power Dialer From Inside Sales was
the source of this problem.
•Users that liberally use tabs can magnify browser issues
•

Polling sidebar component created an issue

•Controller ran unnecessary queries
•

Vendor produce a patch

•Browser issues can linger if users don’t restart

Bottom Line: A 64% Reduction in VF loads

Lessons Learned
▪ It’s easier to find the culprit when you isolate the scenario.
▪ Don’t make assumptions. Let the data guide you.
• Just because it’s an AppExchange app, doesn’t mean it’s correct.

▪ Trust, but verify

Reporting Usage Is Off The Charts!
•~50% of all db gets come from reports
•Daily Report Stats:
•~4000 reports being run daily
•45K-60K report executions daily
•10B-15B gets from reports
•6 users were using 9-13% of their report gets daily.

So Where Would You Start?

Why 4000 Unique Reports?
Lack of Report Governance
Anyone can create any report they want
Run it as often as they want
Many reports were are the same or almost the same
Lather, Rinse, Repeat Problem with bad reports

➢ Restrict who can create reports
➢ Restrict reporting access to some objects.
➢ Establish process to collect reporting requests
➢ Create in demand reports, so they can be shared.
➢ Use scheduled reports and dynamic dashboards
➢ Training, Training, Training

Bottom Line: A work in progress…

Why 45k-60k Report Executions Per Day?
Six

6 users routinely
executed a set of similar
reports thousands of
times / day.
It turns out they were
using a browser script to
continually refresh.

What Would You Do?

Possible Solutions
Restrict Who Can Run Reports

Customer indicated that they couldn’t do that

Tell users to stop running the script

This was done, but wasn’t immediately effective.

Restrict Login Hours

Customer wasn’t willing to do that just yet.

Improve the report

Done (see improvement in db gets)

Implement workflows

Tip:

Planned

What you see
as the
problem, could
simply be
another
symptom.

Bottom Line: A 34% Reduction in the Execs

Why 10-15B Db Gets Are Coming From Reports?
Problems

Solutions

❑ Hundreds of unselective reports that have
> 1M gets/exec

➢Restrict Who Can Create Reports

❑ Many unselective reports that have 15M35M gets/exec

➢Your job doesn’t stop with implementing, you
need to train them (cheatsheets, index lists,
sample reports).

❑ Two key report profiles contribute ~30% of
overall get count

➢Revisit the project to audit, profile, and optimize.

Document available indexes

Primary keys

• Id
List of Indexed Fields
• Name
• OwnerId
Foreign keys

•
•
•
•

Lookup
Master-detail
CreatedById
LastModifiedById

Audit dates

•
•
•
•

CreatedDate
LastActivityDate
LastModifiedDate
SystemModstamp

Custom fields

• Unique
• External ID

Need Additional Indexes?
▪

Salesforce support can create single and two-column custom indexes on most fields (with
the exception of multi-picklists, formula fields that reference other objects, and Long
Text Area/Rich Text Area)

▪

Open a case
➢
➢

Bind Variables

➢

Org ID and user ID
who would run the query

➢

▪

Sample Query

Suggested index – OPTIONAL

If they create an index, then SAVE and DOCUMENT where the index was created

Understand SOQL query optimization
Cheat Sheet: Selectivity Rules
Standard indexes
• Simple predicate targets < 20% of total records or 666K
• AND predicate targets < 20% of total records
• OR predicate targets < 10% or 333K of total records
Custom indexes
• Simple predicate targets < 10% of total records or 333K
• AND predicate targets < 666K of total records
• OR predicate targets < 10% or 333K of total records
LIKE
• Tests first 100K rows for selectivity
Predicates that can lead to full table scans
• NULL

• Not equal
• Contains
• Not In

• Does not contain
• Leading wildcards
• Formula fields

Potential Improvements Identified
❑Key Opportunity Report
•

9-13% of total report gets/day

❑Custom Object Report
•

0-16% of report buffer gets /day

❑Various Account Reports
❑Various Lead Reports
❑Various Opportunity Reports

Can

’t In

dex
WHERE Opportunity.Writeup_Status_del__c =
'Needs Details‘
WHERE Opportunity.Writeup_Status_del__c =
'Needs DQ' • This filter field is a complex formula field.
✓ Create sister field using trigger.
✓ Index sister field.
✓ Modify dependent reports.

❑ Key Opportunity Report
•


❑ Custom Object Report
•


❑ Various Account Reports
❑ Various Lead Reports
❑ Various Opportunity Reports

WHERE Call_List_Priority__c IS
[NOT] NULL
OR Call_List_Priority__c < '.
00000000000000000201‘
• ‘<‘ and ‘>’ operators can’t optimize text fields
✓ Investigate process that populates this field
✓ Retype field as NUMBER
✓ Modify reports so < operator can be optimized
✓ Index field

❑Key Opportunity Report
•


❑Custom Object Report
•


❑Various Account Reports
❑Various Lead Reports
❑Various Opportunity Reports

•
•
•
•
•

Using non-selective queries
Customer has wide objects (i.e. Oppty)
Determine appropriate selective field
Index field
Create Skinny Tables

Bottom Line: A 98% Reduction in Db Gets

Lessons Learned
▪ Report on reports to isolate the problem
• Cost of individual reports
• Number of report runs per day
• Non-selective queries
• Problematic queries

▪ Report Governance
• Who is the author of problematic reports?
• Custom Report Types models that the masses can customize

▪ Is it really a reporting problem?
• Data Model
• Workflow, Business process, etc.

What’s Wrong With Our Migration?
Customer expressed concerns because using bulk
API uploaded insert of 17k accounts and it took 27
minutes with workflows, validations, triggers.

What’s wrong here?
They also requested that we turn
code coverage to zero.

Why?

What We Found
Tip:

Follow Best
Practices. They’
ve been created
for a reason.

We suggested adjusting batch sizes on bulk
loads from the default to a lower number. A
value of 60 was found to be optimal.

DupeBlocker was in use and the vendor, advises
turning off triggers during migrations. They update a
custom object record during account updates / inserts
/ deletes, which can cause significant contention
problems that slow down bulk DML operations.

The request to turn code coverage tests to 0%
was related to poorly constructed tests that
required triggers to be active. This is clearly at
odds with Salesforce Best Practice. The
below was provided as a workaround.

if(custom_setting__c.getInstance().disable_all_triggers__c == true)
return;

Bottom Line: 66% Load Time Improvement

Disable actions that fire on insert
Triggers
Validation Rules

Workflow Rules

Defer sharing calculations

OR …
… load with Public default sharing

Just make
sure you turn
it back on
again!!!

Prep your data to avoid overhead

What We Found

Tip:

Upon further investigation, we
found:

What’s the
concern here?

Trust, but verify.

Lessons Learned
▪ Trust, but verify
• Initial reports of causality may be misleading
• Follow the data to the cause
• Non-selective queries
• Problematic queries

▪ Follow Best Practices
• Prep your data in advance for the best results
• Understand how to structure your bulk operations
• You may need to turn off sharing and other automatic functionality to improve
performance.

Architect Core Resource page
• Featured content for architects
• Articles, papers, blog posts, events
• Follow us on Twitter
Updated weekly!
http://developer.force.com/architect

Resources
Apex Governor Limits
http://www.salesforce.com/us/developer/docs/apexcode/Content/apex_gov_limits.htm

Best Practices for Deployments with Large Data Volumes
http://www.salesforce.com/us/developer/docs/ldv/salesforce_large_data_volumes_bp.pdf

Loading Large Data Sets with the Force.com Bulk API
http://wiki.developerforce.com/page/Loading_Large_Data_Sets_with_the_Force.com_Bulk_API

Report Performance
https://na1.salesforce.com/help/doc/en/salesforce_reportperformance_cheatsheet.pdf

Additional Resources
Bulk API Developers Guide http://www.salesforce.com/us/developer/docs/api_asynch/api_bulk.pdf
Bulk API Errors http://www.salesforce.
com/us/developer/docs/api_asynch/Content/asynch_api_reference_errors.htm

Batch Apex http://www.salesforce.com/us/developer/docs/apexcode/index_Left.
htm#StartTopic=Content/apex_batch.htm

Failing Safe with Apex Data Loader
http://tedhusted.blogspot.com/2012/04/failing-safe-with-apex-data-loader-for.html

Tools
– Data Loader - http://wiki.developerforce.com/page/Data_Loader
– Dell Boomi - http://www.boomi.com/
– IBM CastIron - http://ibm.co/PO0Qv8
– Informatica - http://bit.ly/OeRcCi

Follow the evidence: Troubleshooting Performance Issues

Record Lock Lifecycle
▪ Record Locks = Data Integrity
▪ Salesforce locks a record before executing a DML operation.
-

This is done before the starting the save process.
▪

-

The save process is documented on this page: Triggers and Order of Execution.

Records will remain locked until commit.

▪ Salesforce will wait up to 10 seconds to lock a record before
throwing an UNABLE_TO_LOCK_ROW error.
-

Even if no errors occur, waiting for locks can significantly slow DML operations.

Parent-Child Relationships
▪ Insert of Contact requires locking the parent Account.
▪ Insert or Update of Event requires locking both the parent Contact and
the parent Account.
▪ Insert or Update of Task requires locking both the parent Contact and
parent Account, if the Task is marked as complete.
▪ Insert of Case requires locking the parent Contact and parent Account.
▪ In objects that are part of a master/detail relationship, updating a detail
record requires locking the parent if roll-up summary fields exist.

Multi-threaded Operations
▪ Locking should be taken into consideration for API integrations,
data loads, apex future methods, etc. where requests will be run
in parallel.
▪ Ideally requests that run concurrently should not require the
same locks.
- Different requests can’t update same records
- Different requests can’t update multiple children of the same parent

Prioritize the Data into Tiers

Tier 1 Objects
SFDC
API
Tier 2 Objects

Tier 3: On Premise
SOA

*

Tier 1 : Normal Data
▪ Normal SFDC data
▪ List views, standard reporting, and search
▪ Data set should be ~< 10 Million records
▪ Can include snapshot summary of key data to facilitate query
optimization

Tier 2 : Storage Objects
▪ Custom Objects in a read-only approximation
▪ No standard reporting and search
▪ Use Visualforce pages to make filtered search queries and limit
view to users
▪ Data set should be ~< 50 Million records

Tier 3 : On - Premise Objects
▪ Stored in an on-premise/datawarehouse database
▪ Viewable only through mashups
▪ Integration processes move objects from SFDC to Tier 3, and from
Tier 3 to other Tiers
▪ Part of a larger SOA framework
▪ Data set can be > 50 Million records

Denormalizing Data Increases Performance
▪Select name from contact where Account.
SLA_Serial_Number__c IN :ListOfSerialNums
▪Solution
▪Copy SLA_Serial_Number to a field in Contact (don’t use a formula)
and make the field an External Id
▪OR query for the account IDs with the SLA Serial number first

Batch Apex
▪ Running concurrent Batch Apex jobs on the same record set can
lead to contention.
-

Concurrent jobs will likely perform DML that requires locks on the same records.

▪ One workaround is to parallelize jobs by using an Autonumber field
and a Formula field using the MOD function on the Autonumber
field.
-

This ensures that each job will operate on an entirely different record set.

-

Be careful with records that require locking their parent records.
▪

For example the child in a master-detail relationship.

Batch Apex – Avoid Errors in Bulk DML
global void execute(Database.BatchableContext bc,
List<Account> scope) {
for(Account acc : scope) { /* do something */ }
Database.SaveResult[] results = Database.update(scope,
false);
/* look at results */
}

▪ If an error occurs in this save operation, Salesforce will try to save it
one record at a time.
▪ This performs significantly slower than a bulk save without
errors.

The Key To Good Discovery Questions
▪ Don’t lead the witness.
▪ Confirm answers from multiple sources.
▪ Ask about median, peak, exceptional event volumes.
▪ When you think you’ve got it all, is there anything we’re forgetting?
▪ Don’t just think about the requirements for today. Ask about growth
projections and make some yourself.
▪ Know your governor limits and bulk limits, etc.

Questions To Ask
▪ Stakeholder Expectations

▪ Data Access / Sharing

– What are the performance criteria?

– What is the likely growth in data volumes?

– How long will migration/synchronization take?

– Will the current plan support that growth?

– Are there business-mandated update
windows?

– How can data updates be segmented?

▪ Reporting Requirements
– How many rows are expected in results?
– Do they need to view all results or is paging a
possibility?
– Understand Performance expectations.
– Are Reports Segmented or Filtered?
– Report Samples may drive additional
questions.

– If not, start planning NOW.
– Dig deep on role hierarchy. How many
levels?
– Is there a large number of OR complex
sharing rules?
– How many records are owned by particular
users? (max. vs. median)
– Will they be using Territory Management? If
so, how many levels?

Questions To Ask
▪ Rollback

▪ Data Integration

– What happens if an integration load or synch
fails?

– What data will be native to SFDC vs.
updated from an external master?

– How long will rollback take?

– Will changes be driven from SFDC or the
external system?

– What services are affected during a rollback?
– What is the mitigation plan?

– How frequently will it change? Update
windows or immediately?
– Do you need workflows or triggers?

▪ Purging / Archiving Data
– Is some data transient?

▪ Replication

– What data can be archived?

– Do I need backups for compliance?

– When can it be archived?

– What is my backup strategy?

– What are the restore/recover requirements?

– When and how can I archive the different
types of data in Salesforce?

– What are the Compliance / legal requirements
on access / availability?

Analyzing Performance – Developer Console
▪ Use the Developer Console to analyze server-side performance.
▪ Apex debug logs will be generated for every server request you perform
while the window is open.
▪ Several tools are available in the Developer Console to find performance
hotspots.

Leveraging Bulk API Best Practices
▪ Use Parallel Mode When possible.
–

See FAQ for scenarios when you would serial processing

▪ Organize Batches to Minimize Lock Contention
▪ Be Aware of Operations that Increase Lock Contention
–
–
–
–
–

Creating new Users
Updating ownership of records with private sharing
Updating user roles
Updating territory hierarchies.
SOLUTION: Create separate jobs to process data in serial mode.

▪ Minimize # of Fields
–

Foreign keys, lookup relationships, and summary fields are frequent culprits.

▪ Minimize or better yet Eliminate Workflow Actions.
▪ Minimize or Eliminate Triggers
▪ Optimize Batch Size
–
–
–

▪
▪
▪
▪

any batch that takes more than 10 minutes is suspended and returned to the queue for later processing. The best course of action is
to submit batches that process in less than 10 minutes.
Techniques
Start with 5000 records and adjust the batch size based on processing time. If it takes more than five minutes to process a batch, it
may be beneficial to reduce the batch size. If it takes a few seconds, the batch size should be increased. If you get a timeout error
when processing a batch, split your batch into smaller batches, and try again.

Defer complex sharing rules
Speed of operation; Insert then Update then Upsert (involves implicit query)
Group and sequence data to avoid parent record locking
Remember database statistics calculate overnight, wait to do performance testing

Leveraging Batch Apex Best Practices
▪

Consider setting it to the maximum that the execute can support without running into governor
limits. Default is 200.

▪

If you are operating on large volume of data, limit the Query Locator size and consider running
concurrent Batch Apex jobs.

▪

Chain Batch Apex Jobs:
Using Apex Scheduler
In the finish method of the Batch Apex job, create an Apex Scheduler instance to run just
once and schedule the next Batch Apex job.
• Using Email Services
Create an Apex class that implements Message.InboundEmailHandler interface,
Configure Inbound Email Service Handler,
In the finish method of the Batch Apex job, send an email to the Inbound Email Handler,
In the Inbound Email Handler class, submit the next Batch Apex job.

Follow the evidence: Troubleshooting Performance Issues

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