Slow performance is observed on a query of an indexed attribute on a large feature class in an enterprise geodatabase.
* A SOL trace reveals that the attribute index is not being used in the query
* The indexed attribute values have a high degree of uniqueness
* The delta tables do not have very many rows
Which tool should be used to resolve this issue?
Answer : A
When experiencing slow performance on a query of an indexed attribute in a large feature class within an enterprise geodatabase, and a SQL trace reveals that the attribute index is not being utilized despite the attribute values having a high degree of uniqueness and the delta tables containing few rows, the appropriate action is to rebuild the indexes.
Understanding Indexes in Enterprise Geodatabases:
Indexes are critical for enhancing query performance in databases. They allow the database management system (DBMS) to locate and retrieve data efficiently. Over time, as data is inserted, updated, or deleted, indexes can become fragmented or outdated, leading to suboptimal query performance.
ARCGIS PRO
Rebuilding Indexes:
The Rebuild Indexes tool in ArcGIS Pro is designed to rebuild existing attribute or spatial indexes in enterprise geodatabases. This process reorganizes the index structure, ensuring that the DBMS can effectively utilize the indexes during query execution.
ARCGIS PRO
Steps to Rebuild Indexes:
Access the Rebuild Indexes Tool:
In ArcGIS Pro, navigate to the Analysis tab and click on Tools.
In the Geoprocessing pane, search for and select the Rebuild Indexes tool.
Configure the Tool Parameters:
Input Database Connection: Specify the connection to your enterprise geodatabase.
Include System Tables: Decide whether to include system tables in the rebuild process. Including system tables can help maintain the overall health of the geodatabase but may increase processing time.
Execute the Tool:
Click Run to initiate the index rebuilding process. Monitor the progress and ensure the process completes without errors.
Alternative Options:
Compress Geodatabase: The Compress operation reduces the size of the geodatabase by removing redundant states and versions. While it can improve performance, it doesn't directly address index fragmentation.
Analyze Datasets: The Analyze Datasets tool updates database statistics, which helps the DBMS optimize query execution plans. However, if indexes are fragmented, analyzing datasets alone may not resolve performance issues.
Given the symptoms described---specifically, the attribute index not being used in queries---the most effective solution is to rebuild the indexes to ensure they are properly structured and utilized by the DBMS during query execution.
An organization needs to reduce the number of RDBMS users. ArcGIS Enterprise and ArcGIS Pro are implemented. Editors need to isolate edits and ensure that edits are reviewed before becoming public.
Which editing model should the GIS administrator implement?
Answer : B
Understanding the Scenario:
Editors need to isolate their edits so that changes are not immediately visible to others.
Edits must be reviewed before becoming public, indicating a requirement for a structured approval process.
The organization aims to reduce the number of RDBMS users, which suggests centralized management of access and permissions.
Editing Models Overview:
Branch Versioning: Designed for web-based workflows and does not require direct RDBMS access for each editor. However, edits made in branch versioning are inherently collaborative and are not isolated unless explicitly controlled through a branch-per-user workflow, which adds complexity.
Traditional Versioning:
Supports isolated editing through private versions.
Editors can create their own versions, make changes, and submit them for review by reconciling and posting to the default version.
Direct access to the RDBMS is centralized, reducing the need for individual RDBMS users.
Nonversioned Editing: Does not support isolated edits or versioned workflows, making it unsuitable for this scenario.
Steps to Implement Traditional Versioning:
Register the feature class as versioned in the enterprise geodatabase.
Allow editors to create private versions for making isolated edits.
Implement a workflow for reconciling and posting edits after review.
Reference:
Esri Documentation: Traditional Versioning.
Why the Correct Answer is B: Traditional versioning meets all requirements: it isolates edits, allows for review before posting, and reduces the number of RDBMS users through centralized version management. Branch versioning is web-centric and lacks the structured review process, while nonversioned editing does not support isolation or versioning.
An organization needs to edit GIS data using web services. The data must be stored locally in the organization's servers. Specific business fields must be indexed in the database to help with performance.
Which storage should be used for the data?
Answer : A
Comprehensive Detailed Step-by-Step Explanation with All Enterprise Geodata Reference:
An Enterprise geodatabase is the most appropriate choice for this scenario due to the following reasons:
1. Requirement to Store Data Locally on Organization's Servers
An Enterprise geodatabase allows organizations to store GIS data locally in their own database management systems (DBMS), such as PostgreSQL, SQL Server, or Oracle.
This meets the requirement of maintaining control over data storage and ensuring the data resides within the organization's infrastructure.
2. Editing GIS Data via Web Services
Enterprise geodatabases seamlessly integrate with ArcGIS Server, enabling data editing via web services.
Organizations can publish feature services to allow authorized users to edit GIS data in real-time or in a disconnected environment (via sync).
These services support advanced editing workflows, including versioning and conflict resolution.
3. Indexing Specific Business Fields for Performance
Enterprise geodatabases offer robust indexing options to enhance query and editing performance.
You can:
Create attribute indexes on fields that are frequently queried.
Use spatial indexes to improve the speed of spatial queries.
This level of customization helps meet the performance demands of specific business workflows.
4. Advantages Over Other Storage Options
File Geodatabase:
While it is suitable for smaller datasets and local storage, it does not support multi-user editing, integration with web services, or advanced indexing for business fields.
Hosted Relational Database:
This option is part of ArcGIS Online or ArcGIS Enterprise managed services and stores data in the cloud, which contradicts the requirement for local storage.
It also does not provide the same level of control or indexing capabilities as an enterprise geodatabase.
Reference from Esri Documentation and Learning Resources:
Enterprise Geodatabases---ArcGIS Pro Documentation
Configuring Indexes in Geodatabases
Publishing Feature Services for Editing
Conclusion:
An Enterprise geodatabase not only meets all the stated requirements (local storage, web service editing, and indexed fields for performance) but also provides additional scalability, security, and multi-user editing capabilities.
A GIS data administrator frequently changes the map based on definition queries. A noticeable lag occurs when changing the parameter value of the definition query.
Which action should be taken?
Answer : A
Scenario Overview:
The GIS data administrator is experiencing lag when changing the parameter value of a definition query.
Definition queries dynamically filter data based on attribute values. Slow performance often indicates inefficient attribute searches.
Solution: Add Attribute Index
An attribute index allows the database to quickly locate rows based on values in the indexed column, significantly improving query performance.
When definition queries rely on non-indexed fields, the database must scan the entire dataset to filter records, leading to noticeable delays.
Steps to Add Attribute Index:
In ArcGIS Pro, open the Attribute Indexes tool.
Select the feature class or table used in the definition query.
Specify the field(s) that the definition query is based on.
Click Run to create the index.
Alternative Options:
Option B: Add Spatial Index
Spatial indexes optimize spatial queries (e.g., finding features within an area). This does not address attribute-based definition query lag.
Option C: Recalculate Extent
Recalculating the extent corrects boundary discrepancies in spatial datasets but has no impact on attribute query performance.
Thus, adding an attribute index is the correct action to resolve lag in definition queries.
A user accidentally deletes an enterprise geodatabase feature dataset.
Which technology should be used to resolve the issue?
Answer : B
Understanding the Scenario:
An enterprise geodatabase feature dataset is accidentally deleted.
The organization needs to recover the dataset to its original state.
Available Technologies:
High Availability: High availability setups (e.g., failover systems) ensure continuous access to geodatabases during hardware or software failures. However, high availability does not restore accidentally deleted data.
Backup: A backup is a snapshot of the geodatabase taken at a specific point in time. It allows administrators to restore deleted datasets or recover from data loss scenarios.
Archiving: Archiving tracks historical edits in versioned geodatabases but does not provide recovery for accidentally deleted datasets.
Steps to Recover the Dataset:
Identify the most recent backup of the enterprise geodatabase.
Restore the geodatabase or extract the specific feature dataset from the backup.
Verify the restored data and synchronize it with ongoing updates if necessary.
Reference:
Esri Documentation: Backup and Restore.
Best Practices for Data Protection: Guidelines for implementing regular backups to prevent data loss.
Why the Correct Answer is B: A backup is the most reliable solution for recovering an accidentally deleted feature dataset. High availability ensures uptime but does not address data recovery, and archiving tracks edits rather than preserving entire datasets.
A wells feature class has one row per well. A well_inspections table has one row for each time a well was inspected. All inspection dates need to be displayed as labels clustered around each well on the map.
Which kind of association should be used to meet this requirement?
Answer : B
Scenario Overview:
The wells feature class has one row per well.
The well_inspections table has one row for each inspection of a well.
Inspection dates from the well_inspections table need to be displayed as labels clustered around each well on the map.
The goal is to establish a connection between these two datasets without permanently joining them, as the data is being displayed dynamically (inspection dates are clustered around the wells).
Relates in Geodatabases:
A relate is a type of table association in which tables are linked by a common key field but remain separate.
Relates allow for dynamic queries to retrieve related records without duplicating or permanently associating the data.
Using a relate, you can query all inspection dates for a specific well dynamically, display them on the map as labels, and preserve the integrity of both the wells and inspections datasets.
(ArcGIS Documentation: Relates)
Alternative Options:
Option A: Join
A join merges two tables into one virtual table, based on a shared key. However, this approach is static and inappropriate for displaying dynamically clustered labels since the tables would need to be rejoined after every update.
Option C: Relationship Class
A relationship class is a more permanent association that enforces rules between two datasets. It is ideal for maintaining relationships between data but is unnecessary for dynamically labeling inspection dates on the map.
Thus, a relate is the most efficient and appropriate option for this scenario.
An organization has a web service that must always be available. This service reads data from a feature class in an enterprise geodatabase. The GIS administrator needs to update the schema of the feature class.
Which workflow should be used?
Answer : A
Scenario Overview:
The organization has a web service that must always be available.
The service reads data from a feature class in an enterprise geodatabase.
The GIS administrator needs to update the schema of the feature class.
Why Disable Schema Locking?
By default, ArcGIS services enforce schema locking to ensure data consistency while the service is active. This prevents any modifications to the feature class schema (e.g., adding fields, altering attributes) while the service is running.
Disabling schema locking allows schema updates to occur without disrupting the service's availability. (ArcGIS Documentation: Schema Locking)
Steps to Disable Schema Locking:
Access the ArcGIS Server Manager.
Locate the web service and open its service properties.
In the advanced settings, disable the schema locking option.
Perform the required schema updates (e.g., adding fields or modifying the feature class).
Re-enable schema locking if necessary for normal operation.
Alternative Options:
Option B: Run the Alter Field geoprocessing tool
This tool modifies fields but cannot execute schema changes while schema locks are active.
Option C: Delete the spatial index
Deleting the spatial index is unrelated to schema changes and could degrade query performance.
Thus, the correct workflow is to disable schema locking on the service to allow schema changes without disrupting the web service.