Overview
Streams are a key model component. They represent a structured store of data within PhixFlow receiving data from one or more components, processing it then storing it.
When you make changes to streams and stream attributes, PhixFlow automatically publishes them to the stream data tables in the database; see Publishing Streams.
Stream Properties
Basic Settings
Updating a static stream
In general, static streams are not updated during an analysis run that is initiated on another stream in the model. The exception is when an incoming push pipe is triggered, as this will force the stream to update itself.
Instead, to update the data in a static stream you must run analysis directly on the stream via:
- the model
- a task plan.
Select the time period for the stream:
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As transactional streams need a UID
attribute, PhixFlow automatically creates this stream attribute if it does not already exist.
This option affects the following items for which this is the backing stream:
- stream views
- dashboards
- card layout components.
If no option is is selected, PhixFlow assumes the default data range is All.
You can override this setting using the options Use Custom Data Range and Data Range available:
You cannot override this setting for a stream view.
Select the stream type. The type indicates the function that operates on the data.
- Aggregate Stream
- Calculate Stream
- CalculateBySet Stream
- Cartesian Stream
- Merge Stream
Select a loop pipe from the list of those available.
A loop pipe links the stream back to itself. It compares new data records to the existing data records. If there is a repeated record PhixFlow uses the new one in the stream and marks the old one as superseded
.
This check box is available when the Period is Transactional.
When Audit Manual Changes is first set, the attributes UpdateAction
, UpdatedByName
, UpdatedByID
and UpdatedTime
will be created if they do not already exist. If you do not require these attributes, delete them. For the UpdatedByName
attribute, PhixFlow creates a field of 250 characters. (In versions up to 8.0.4, the field was 50 characters long.)
UpdateAction
must be set to the type of action, such as INSERT, UPDATE or DELETE. The other attributes will be populated if they exist on the stream:
UpdatedByName
- the name of the user that performed the update,UpdatedByID
- the internal id of the user that performed the updateUpdatedTime
- the date and time the update was made
Attributes
The grid contains a list of the stream attributes in the stream. This section has a toolbar with standard buttons andThe grid lists the attributes (data columns) in the stream data. To edit the properties of an attribute, double-click the attribute name to open the Attribute properties.
To remove an attribute from the stream, select the attribute and clickTo add an existing attribute to the list:
ClickTo edit only the expression:
- Right-click an attribute name to display the context menu.
- Select Edit the expression field.
- PhixFlow opens a simple text editor box
- Make changes to the attributes expression.
- Click to save your changes.
do ( $aRange = [], addElement($aRange, rng.RangeFrom), addElement($aRange, rng.RangeTo), $bRange = [], addElement($bRange, $aRange), $bRange )
Where rng.RangeFrom = 500 and rng.RangeTo = 1000, the above example evaluates to [[500,1000]], which is a list containing 1 element, which is itself a list containing 2 elements. An Input Multiplier that evaluates to [3,4,7,8] would run the Stream 4 times.Because Input Multipliers are evaluated first in the PhixFlow Timing Cycle they are often used to look up values that can be passed to Database or other Collectors.
For example :
ifNull(in.ASSET, [1,10,12] , // else do [5,7] )
will create 3 records for every record in the stream if in.ASSET contains a value (setting _type = 1, 10 and 12 in each case). Otherwise it will create 2 records for every record in the stream (and set _type = 5 and 7). An Output Multiplier may also evaluate to a record, or a group of records. For example an Output Multiplier with the expression:do( lookup(lkin, $num = in.BNumber), lkin )
will return a list of records which match the lookup on the lkin pipe. In this case the required data can be extracted from the Output Multiplier using the following expression :
do ( $values = _type, $values.account_num )
If the output multiplier expression evaluates to _NULL, an empty list of values or an empty list of records then a single output record will be produced with _type set to _NULL, _NULL or an empty record respectively.
Select Records to Output
You can select a subset of records to output to the next modelling object. You select records using the data in any attribute that is in the stream output. Enter an expression that should evaluate to true or false (equivalently 1 or 0).
When the expression evaluates to true or 1, the records found by the expression are selected and output to the next modelling object.
For example:
- A stream containing data about accounts has an attribute called "active".
- You only want to include "active" accounts in the following streams.
- Active accounts have the value 1.
To select active accounts, enter the expression _out.active
.
All records that have the active attribute set to any other value are ignored.
Actions
This section has a toolbar with standard buttons. The grid contains a list of actions that operate on the stream.
To edit the properties of an action, double-click its name. To add an action to the list, clickInsert excerpt | ||||||||
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Available when Period is Transactional.
This can be useful where you want to make sure that two analysis runs do not attempt to update the same records at the same time e.g. as a result of two people selecting the same records in a view and then hitting the same action button at the same time to process those records.
Any additional analysis tasks submitted while this stream is waiting to start, or while it is generating data, will wait until this stream has completed its analysis before they start.
Access Permissions
By default, the permissions to access stream data is set in System Configuration → Allow access to data by default.You can add specific user groups to restrict access to the stream; see Common Properties → Access Permissions.
Stream Item Actions
This section has a toolbar with standard buttons. The grid contains a list of stream item actions that can update records in the stream.
To edit the properties of a stream item action, double-click its name. To add a stream item action to the list, clickViews
This section has a toolbar with standard buttons. The grid contains a list of the data views for this stream.
To edit the properties of an stream view, double-click its name. To add a stream view to the list, clickSort Orders
This section has a toolbar with standard buttons. The grid contains a list of the sort orders for this stream.
To edit the properties of a sort order, double-click its name. To add a sort order to the list, clickRelations
This section has a toolbar with standard buttons. The grid displays a read-only list of the relationships that this stream has. Double-click a relationship to display it's properties; see Relationship.
Filters
This section has a toolbar with standard buttons. The grid contains a list of the filters that can be applied to this stream and can be added to this stream's views.
All filters in this list are available in the default view for this stream. For stream views that you create, in the View properties tab → Filters section, you can add filters. The list of available filters is populated by the filters defined for the stream.
To edit the properties of a filter, double-click its name. To add a filter to the list, clickTip |
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In a stream view grid, the header row has a drop-down list of filters. The drop-down list is populated by the filters that are selected on the stream view. The filters must first be defined for the stream here. |
Inputs
This section has a toolbar withNote |
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This list can include pipes that have no input. This occurs if the source stream has been deleted or if a model has been moved to a different PhixFlow instance (export/import), leaving behind a referenced stream. Any pipes with no input are highlighted in yellow. To resolve pipes with no input you can:
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The following properties affect the number of data records a user can download from a stream view, such as a grid, chart or card; see Download CSV or Excel Data.
Available when Allow Unlimited Downloads is ticked.
Use this section to select the user groups whose members can download an unlimited number of records.
This section has a toolbar with standard buttons andThe grid contains a list of user groups that are exempt from the Stream Download Limit. To add a user group to the list:
ClickUse the following options to specify how PhixFlow manages old data when a stream-data-delete task runs.
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We recommend that you always specify the data retention values for every stream you create.
If no data retention option is set, PhixFlow displays an error in the Errors section, above. |
- Using Tasks and Task Plans for information about tasks.
- Deleting Old Data to see how you can use these values in data management strategies.
Retain All Data
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Streams with Retain All Data ticked never have their data deleted and the data will accumulate. This can lead to performance issues. |
Keep for N Days
The age of data in a streamset is its 'to' date, relative to the 'to' date of the newest valid streamset in the stream.
When a stream-data-delete task runs for a stream and:
- Keep for X Days only is set, PhixFlow deletes stream data that is older than N days.
- Keep for Y Streamsets only is set, PhixFlow keeps the most recent X streamsets and deletes streamsets that exceed X.
- both Keep for X Days and Keep for Y Streamsets are set, PhixFlow deletes the stream data that meets both conditions.
- neither Keep for N Days nor Keep for X Streamsets are set, PhixFlow keeps stream data indefinitely. This can lead to performance issues.
The number of streamsets to keep in the stream.
Keep Superseded for N Days
Enter the number of days to keep superseded records in the stream data.
Tip |
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Remember to keep superseded records for as long as you want the option to roll back the data. For example, when Keep Superseded for N Days is set to 4, you can run roll back on data that was superseded up to 4 days ago. A stream-data-delete task removes superseded records older than 4 days, so PhixFlow no longer has the data to be able to roll it back. |
In a stream where the superseded date is tracked, the stream data contains a mixture of active records and records that have been superseded.
When a stream-data-delete task runs for a stream and:
- Keep Superseded for N Days only is set, PhixFlow deletes data records that were superseded more than N days ago.
- Keep Superseded for X Streamsets only is set, PhixFlow deletes superseded records from the streamsets that exceed X.
- both Keep Superseded for N Days and Keep Superseded for X Streamsets are set, PhixFlow deletes the superseded records that meet both conditions.
- neither Keep Superseded for N Days nor Keep Superseded for X Streamsets are set, PhixFlow keeps superseded records indefinitely. This can lead to performance issues.
Available when Track Superseded Data is selected.
Enter the number of recent streamsets that will retain their superseded data records.
Store Stream Views
This section has a toolbar with standard buttons. In the grid PhixFlow displays a list of the stream views to store for this stream.
Analysis Models
A list of the analysis models that this stream appears on.
Advanced
Only change the advanced properties with advice by PhixFlow support.
Use this property if your database administrator wants to query stream data in the PhixFlow database.
Enter a string in the format v_xxxx
. When the stream is published to the database, PhixFlow creates a stream view. If the stream is deleted, the next system task that runs will clear the associated stream view from the database.
By default, this field is blank and no stream view is created in the database.
See also Configuring Access to Database Views.
- All: indexes on the stream are optimised for selecting from all streamsets (non-historied reads).
- Latest: indexes on the stream are optimised for selecting from the latest streamset (i.e. for historied reads).
- Superseded: indexes on the stream are optimised for self-updating streams which have a mostly superseded records.
- None: no indexes are created on the stream.
- Partitioned: this index scheme is specific to partitioned streams; see Storage Type below. Partitioned streams must use this index scheme, and only partitioned streams can use it.
- Database: Store the data in a regular table within the PhixFlow database. This is the most common option
- Database (Partitioned): Store the data in a partitioned table within the PhixFlow database. This option provides improved performance for rollback and retaining very large streamsets. The option is only available if "partitioning" is available within your database installation.
- In Memory: Data for the Stream will not be written to the database. This option can be used (for example) when you want to aggregate large amounts of unsorted data which can then be written to a stored Stream.
This option relates to an actionflow with a save node that inserts a new stream-item/record into a stream/table. Each new record requires a unique value for the record's primary key. Use this option to specify how PhixFlow generates the primary key value.
- Internal: PhixFlow generates unique primary key values automatically. This is equivalent to setting the stream attribute expression to
_NULL
. Check the stream attr expression doc - Sequence: display the Primary Key Generator Sequence option, in which you can select a sequence of values.
Available when Primary Key Generator is Sequence.
Select a sequence to assign a new value to the primary key attribute of a new stream-item/record; see Sequence.
- new stream item takes the next primary key value in a sequence. This is equivalent to setting the stream attribute expression to
nextValue("sequenceName"
. - Sequence