Query Service and Data Distiller frequently asked questions

To bypass the output row limit, apply “LIMIT 0” in the query. For example:

SELECT * FROM customers LIMIT 0;

One or more of the following solutions are recommended in case of queries timing out.

• Convert the query to a CTAS query and schedule the run. Scheduling a run can be done either through the UI or the API.
• Execute the query on a smaller data chunk by applying additional filter conditions.
• Execute the EXPLAIN command to gather more details.
• Review the statistics of the data within the dataset.
• Convert the query into a simplified form and re-run using prepared statements.

The following steps describe how to display a tabular view of a dataset through the UI, including all nested fields and columns in a flattened form.

• After logging into Experience Platform, select Datasets in the left navigation of the UI to navigate to Datasets dashboard.
• The datasets Browse tab opens. You can use the search bar to refine the available options. Select a dataset from the list displayed.

• The Datasets activity screen appears. Select Preview dataset to open a dialog of the XDM schema and tabular view of flattened data from the selected dataset. More details can be found in the preview a dataset documentation

• Select any field from the schema to display its contents in a flattened column. The name of the column is displayed above its contents on the right side of the page. You should copy this name to use for querying this dataset.

See the documentation for full guidance on how to work with nested data structures using the Query Editor or a third-party client.

If the query has taken a long time on a very small dataset, please contact customer support.

There can be any number of reasons for a query to be stuck while processing. To determine the exact cause requires an in-depth analysis on a case-by-case basis. Contact Adobe customer support to being this process.

A complete list of Adobe customer support telephone numbers is available on the Adobe help page. Alternatively, help can be found online by completing the following steps:

• Navigate to https://www.adobe.com/ in your web browser.
• On the right side of the top navigation bar, select Sign In.

• Use your Adobe ID and password that is registered with your Adobe license.
• Select Help & Support from the top navigation bar.

A dropdown banner appears containing a Help and support section. Select Contact us to open the Adobe Customer Care Virtual Assistant, or select Enterprise support for dedicated help for large organizations.

The anonymous block feature allows you to chain one or more SQL statements that are executed in sequence. They also allow for the option of exception-handling.

See the anonymous block documentation for more details.

There are two ways to implement custom attribution:

1. Use a combination of existing Adobe-defined functions to identify if the use-case needs are met.
2. If the previous suggestion does not satisfy your use case, you should use a combination of window functions. Window functions look at all the events in a sequence. They also allow you to review the historic data and can be used in any combination.

To retrieve error logs for a specific query, you must first use the Query Service API to fetch the query log details. The HTTP response contains the query IDs that are required to investigate a query error.

Use the GET command to retrieve multiple queries. Information on how to make a call to the API can be found in the sample API calls documentation.

From the response, identify the query you want to investigate and make another GET request using its id value. Full instructions can be found in the retrieve a query by ID documentation.

A successful response returns HTTP status 200 and contains the errors array. The response has been shortened for brevity.

{
    "isInsertInto": false,
    "request": {
                "dbName": "prod:all",
                "sql": "SELECT *\nFROM\n  accounts\nLIMIT 10\n"
            },
    "clientId": "8c2455819a624534bb665c43c3759877",
    "state": "SUCCESS",
    "rowCount": 0,
    "errors": [{
      'code': '58000',
      'message': 'Batch query execution gets : [failed reason ErrorCode: 58000 Batch query execution gets : [Analysis error encountered. Reason: [sessionId: f055dc73-1fbd-4c9c-8645-efa609da0a7b Function [varchar] not defined.]]]',
      'errorType': 'USER_ERROR'
      }],
    "isCTAS": false,
    "version": 1,
    "id": "343388b0-e0dd-4227-a75b-7fc945ef408a",
}

The Query Service API reference documentation provides more information on all available endpoints.

The “Error validating schema” message means that the system is unable to locate a field within the schema. You should read the best practice document for organizing data assets in Query Service followed by the Create Table As Select documentation.

The following example demonstrates the use of a CTAS syntax and a struct datatype:

CREATE TABLE table_name WITH (SCHEMA='schema_name')

AS SELECT '1' as _id,

 STRUCT

  ('2021-02-17T15:39:29.0Z' AS taskActualCompletionDate,

    '2020-09-09T21:21:16.0Z' AS taskActualStartDate,

    'Consulting' AS taskdescription,

    '5f6527c10011e09b89666c52d9a8c564' AS taskguide,

    'Stakeholder Consulting Engagement' AS taskname,

    '2020-09-09T15:00:00.0Z' AS taskPlannedStartDate,

    '2021-02-15T11:00:00.0Z' AS taskPlannedCompletionDate

  ) AS _workfront ;

The numbers displayed in the profile dashboard are accurate as of the last snapshot. The numbers generated in the profile export table are dependent entirely on the export query. As a result, querying the number of profiles that qualify for a particular audience is a common cause for this discrepancy.

The most likely cause is that your query is too narrow in scope. You should systematically remove a section of the WHERE clause until you begin seeing some data.

You can also confirm that your dataset contains data by using a small query such as:

SELECT count(1) FROM myTableName

First, check the logs to find out the details of the error. The FAQ section on finding errors within logs provides more information on how to do this.

You should also check the documentation for guidance on how to perform scheduled queries in the UI and through the API.

Be aware, when using the Query Editor you can only add a schedule to a query that has already been created, and saved. This does not apply to the Query Service API.

You can run a query that returns zero rows to get only the metadata in response. This example query returns only the metadata for the specified table.

SELECT * FROM <table> WHERE 1=0

You can create temporary tables to quickly iterate and experiment on a query before materializing it for use. You can also use temporary tables to validate if a query is functional.

For example, you can create a temporary table:

CREATE temp TABLE temp_dataset AS
SELECT *
FROM actual_dataset
WHERE 1 = 0;

Then you can use the temporary table as follows:

INSERT INTO temp_dataset
SELECT a._company AS _company,
a._id AS _id,
a.timestamp AS timestamp
FROM actual_dataset a
WHERE timestamp >= TO_TIMESTAMP('2021-01-21 12:00:00')
AND timestamp < TO_TIMESTAMP('2021-01-21 13:00:00')
LIMIT 100;

Adobe Experience Platform persists data in UTC (Coordinated Universal Time) timestamp format. An example of the UTC format is 2021-12-22T19:52:05Z

Query Service supports built-in SQL functions to convert a given timestamp to and from UTC format. Both the to_utc_timestamp() and the from_utc_timestamp() methods take two parameters: timestamp and timezone.

Convert to the UTC timestamp

The to_utc_timestamp() method interprets the given parameters and converts it to the timestamp of your local timezone in UTC format. For example, the time zone in Seoul, South Korea is UTC/GMT +9 hours. By providing a date-only timestamp, the method uses a default value of midnight in the morning. The timestamp and timezone are converted into the UTC format from the time of that region to a UTC timestamp of your local region.

SELECT to_utc_timestamp('2021-08-31', 'Asia/Seoul');

The query returns a timestamp in the user’s local time. In this case, 3PM the previous day as Seoul is nine hours ahead.

2021-08-30 15:00:00

As another example, if the given timestamp was 2021-07-14 12:40:00.0 for the Asia/Seoul timezone, the returned UTC timestamp would be 2021-07-14 03:40:00.0

The console output provided in the Query Service UI is a more human-readable format:

8/30/2021, 3:00 PM

Convert from the UTC timestamp

The from_utc_timestamp() method interprets the given parameters from the timestamp of your local timezone and provides the equivalent timestamp of the desired region in UTC format. In the example below, the hour is 2:40PM in the user’s local timezone. The Seoul timezone passed as a variable is nine hours ahead of the local timezone.

SELECT from_utc_timestamp('2021-08-31 14:40:00.0', 'Asia/Seoul');

The query returns a timestamp in UTC format for the timezone passed as a parameter. The result is nine hours ahead of the timezone that ran the query.

8/31/2021, 11:40 PM

How should I filter my time-series data?

SELECT a._company  AS _company,
       a._id       AS _id,
       a.timestamp AS timestamp
FROM   dataset a
WHERE  timestamp >= To_timestamp('2021-01-21 12:00:00')
       AND timestamp < To_timestamp('2021-01-21 13:00:00')

When using the CAST operator to convert a timestamp, you need to include both the date and time.

For example, missing the time component, as shown below, will result in an error:

SELECT * FROM ABC
WHERE timestamp = CAST('07-29-2021' AS timestamp)

The correct usage of the CAST operator is shown below:

SELECT * FROM ABC
WHERE timestamp = CAST('07-29-2021 00:00:00' AS timestamp)

The NOT IN operator is often used to retrieve rows that are not found in another table or SQL statement. This operator can slow down performance and may return unexpected results if the columns that are being compared accept NOT NULL, or you have large numbers of records.

Instead of using NOT IN, you can use either NOT EXISTS or LEFT OUTER JOIN.

For example, if you have the following tables created:

CREATE TABLE T1 (ID INT)
CREATE TABLE T2 (ID INT)
INSERT INTO T1 VALUES (1)
INSERT INTO T1 VALUES (2)
INSERT INTO T1 VALUES (3)
INSERT INTO T2 VALUES (1)
INSERT INTO T2 VALUES (2)

If you are using the NOT EXISTS operator, you can replicate using the NOT IN operator by using the following query:

SELECT ID FROM T1
WHERE NOT EXISTS
(SELECT ID FROM T2 WHERE T1.ID = T2.ID)

Alternatively, if you are using the LEFT OUTER JOIN operator, you can replicate using the NOT IN operator by using the following query:

SELECT T1.ID FROM T1
LEFT OUTER JOIN T2 ON T1.ID = T2.ID
WHERE T2.ID IS NULL

The system does not have indexes as it is not a database but it does have other optimizations in place tied to the data store. The following options are available to tune your queries:

• A time-based filter on timeseries data.
• Optimized push down for the struct data type.
• Optimized cost and memory push-down for arrays and map data types.
• Incremental processing using snapshots.
• A persisted data format.

There are three approaches to restricting access. They are as follows:

• Use SELECT only statements and give datasets read only access. Also, assign the manage query permission.
• Use SELECT/INSERT/CREATE statements and give datasets write access. Also, assign the query manage permission.
• Use an integration account with the previous suggestions above and assign the query integration permission.

Yes. Data can be extracted from Query Service and there is also the option to store the results in CSV format via a SQL command.

There are two ways to save the results of a query when using a PSQL client. You can use the COPY TO command or create a statement using the following format:

SELECT column1, column2
FROM <table_name>
\g <table_name>.out

Guidance on the use of the COPY TO command can be fond in the SQL syntax reference documentation.

A common cause for this problem is querying time-series data without a time filter. For example:

SELECT * FROM prod_table LIMIT 1;

Should be written as:

SELECT * FROM prod_table
WHERE
timestamp >= to_timestamp('2022-07-22')
and timestamp < to_timestamp('2022-07-23');

When the system is connected to Query Service, it is connected to an interactive or batch processing engine. This can result in longer loading times to reflect the processed data.

If you would like to improve the response times for your dashboards, you should implement a Business Intelligence (BI) server as a caching layer between Query Service and BI tools. Generally, most BI tools have an additional offering for a server.

The purpose of adding the cache server layer is to cache the data from Query Service and utilize the same for dashboards to speed up the response. This is possible as the results for queries that are executed would be cached in the BI server each day. The caching server then serves these results for any user with the same query to decrease latency. Please refer to the documentation of the utility or third-party tool that you are using for clarification on this setup.

The history_meta() method is used to access a snapshot from a dataset. Previously, if you were to run a query on an empty dataset in Azure Data Lake Storage (ADLS), you would receive a 58000 error code saying that the data set does not exist. An example of the old system error is displayed below.

ErrorCode: 58000 Internal System Error [Invalid table your_table_name. historyMeta can be used on datalake tables only.]

This error occurred because there was no return value for the query. This behavior has now been fixed to return the following message:

Query complete in {timeframe}. 0 rows returned.