Overview
A pipe is a connector that links two elements in a PhixFlow model and sends data from the input to the output. Pipes allows you to control which attributes and which records from the input are delivered by to the output, although in most cases - with minimal configuration - you will get all columns and the records from the current run.
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By default, the Read Future Data checkbox check box is not ticked. This means pipes ignore any stream sets with dates in the future relative to the stream set you are generating. You want to ignore future stream sets when you rebuild an old stream set, because you want the pipe to retrieve the same data on the rerun as it retrieved when the stream set was first built.
When you run analysis on a stream with a transactional period, it is possible that as your analysis is still running, a different run can start and complete. This run can generate additional stream sets on the input stream with a future data relative to the date of the stream set you are generating. For transactional input streams, you want the pipe to use these future streams. To do this, tick the Read Future Data checkbox check box.
Filter
Filters are made up of a set of clauses; each clause in turn contains a number of conditions. These conditions must be satisfied for data to be passed through the pipe.
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Country Is in ["England","France","Germany"] fx
Sort/Group
Use this section to group and sort data as it comes through the pipe. for lookup pipes, this section is called Order/Index. This section has:
- a toolbar with standard buttons
- a grid that lists the attributes that you want to sort or use to group
- below the grid are the following options:
| Field | Description |
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| Maximum Number of records per Group | Enter an upper limit for grouped records. When collating the input records into groups, PhixFlow uses the specified sort order. When it has added the maximum number of records, any more records for the group are ignored. This can be useful if you want the most recent record for an attribute that has many records. - Tick the Group checkbox check box for the attribute you want to use for grouping.
- On an appropriate date attribute, apply a (Z-A) sort order.
- Set the Maximum Number of Records to 1.
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| Index Type | This field is available for pipes with the Type= Look-up. Look-up pipes can be configured for fast "indexed" access to cached data collected from external tables, files or from other streams. Indexed access is controlled through configuring a pipe with an index and setting index expressions on grouping attributes. If the Type field on the Pipe is set to 'Look-up' then the field "Index Type" becomes available. This can have the value "None" meaning that there are no index keys or "Exact Match", "Best Match" or "Near Match" as described below: - Exact Match: The pipe retrieves data from its cache based on an exact match look-up with the values provided after evaluating the index expressions on the "Group By" attributes.
- Best Match: The pipe retrieves data from its cache based on a "Best Match" look-up after evaluating the index expressions on the "Group By" attributes.
Note: The last Group By Attribute with a key expression is used for the best match lookup. The index keys on any Group By attributes with a lower sequence number are used as an initial "Exact Match" to find the set of data on which to do the "Best Match". The "Best Match" is defined as the longest key value which matches the evaluated index expression.
- Near Match: The pipe will retrieve data from its cache based on a "Near Match" look-up after evaluating the index expressions on the "Group By" attributes.
Note: the last Group By Attribute with a key expression is used for the near match lookup. The index keys on any Group By attributes with a lower sequence number are used as an initial "Exact Match" to find the set of data on which to do the "Best Match". When "Near Match" is selected, an additional field appears where you can enter an expression which should evaluate to a number representing the allowed number of edits (e.g. deletions, insertions, substitutions and transpositions) which can be made when comparing the result of the index expression to the index key in order to achieve a match. For example if the index key is "Smyhte" and the result of the index expression is "Smith" this would still be a match providing that the allowed number of edits is 3 or more (i.e. substitute the 'i' for a 'y', transpose the 't' and the 'h' and then insert an 'e' at the end).
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to open the list of attributes in the input stream - drag a stream attribute into the grid.
To remove an attribute, click
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in the toolbar.
To set the sort or group properties for an attribute, double-click its name in the grid. If you want to create a new attribute that is not present in the input stream, in the section toolbar, click
. PhixFlow opens the attribute's sort properties:
| Field | Description |
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| Attribute | For input stream attributes, PhixFlow displays the attribute name. (Read-only) For a new attribute, enter a name. |
| Order | Enter the number for the order the attribute appears in the grid and the order in which it is processed. Other attributes are renumbered. |
| Direction | Select the sort order - (A-Z) to sort data records in ascending order, e.g. A to Z, 1 to 9, earliest to latest date.
- (Z-A) to sort data records in descending alpha-numeric order, e.g. Z to A, 9 to 1, latest to earliest date.
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by default, data is not grouped. | Insert excerpt |
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to group data records by the value in this attribute. If this attribute is part of the candidate key set, you must tick the Group checkbox check box. Otherwise, the attributes will be used only to sort the data in the candidate set. |
| Index Expression | This field is available for lookup pipes with an Index Type option selected. Look-up pipes can be configured for fast "indexed" access to cached data. This data is collected from external tables, files or from other streams. Indexed access is controlled through configuring a pipe with an index and setting index expressions on "Group By" attributes here. |
| Audit Summary | See Common Properties. |
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In some cases, you may have a pipe connected to a database collector, which pulls data from an external database table. In these cases, the fields in the database must have matching attribute names in the output stream. You can refer to it using the format _out.AttributeName |
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You cannot aggregate data from attributes if the pipe's input is from: If you need to aggregate data from a database collector, you can use an SQL query. |
This section has:
- a toolbar with standard buttons
- a grid that lists the attributes that you want to aggregate.
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| Data Expected | This checkbox check box is available when the pipe Type is Push or Pull. | Insert excerpt |
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means the pipe may receive no data from its input during an analysis run. | Insert excerpt |
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means PhixFlow reports an error if the pipe receives no data from the input datasource, collector or stream during an analysis run. |
| Allow Incomplete Stream Sets | | Insert excerpt |
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to complete a stream set before passing the data to the output stream. During the analysis run, PhixFlow pulls data into the input stream until the stream set is complete. If it cannot complete the stream set, PhixFlow reports an error message. PhixFlow cannot complete a stream set if: - either the input stream is set to be
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- or all of the pipes reading from the stream are static.
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PhixFlow ignores incomplete stream sets in a static input stream and does not report an error. | Tip |
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You must tick this checkbox check box on all the pipes that will read from a static (or effectively static) input stream in the analysis run. PhixFlow will report an error if there is any pipe trying to complete the stream set during the analysis run. |
Pipes that are not used in the analysis run do not try to complete a stream set, so will not report an error. (Unused pipes can occur if they lead to streams on branches of the model that are not being run.) |
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This option is useful for lookup pipes. PhixFlow uses the pipe cache when it looks-up data from streams or database collectors. For efficiency, the records are cached (stored temporarily in memory) so that if the same set of records need to be looked up again they are readily available without going back to the database.Enter a number to set a limit on the data cache size available for the pipe. You need to estimate the largest number of records that the lookup pipe will return on a single read. Check whether PhixFlow is looking up: - many records
The pipe does a single lookup onto a stream or database table to get a large number of records in one go, for example 10,000 records. - few records may times
The pipe does many lookups, getting a small number of records for each lookup, for example, 10 records at a time. In this case, PhixFlow is usually using a key value, such as an account number, to get the data. The key value is:- for a stream - the attribute used to filter the pipe
- for a database collector - a condition in the database query. For example:
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WHERE AccountNumber = _out.AccountNum |
If you do not set a limit for the cache, PhixFlow uses the system default set in System Configuration → System Tuning → Maximum Pipe Cache Size. | Expand |
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| In the log for an analysis run, which is available in the system console, PhixFlow reports warnings when a single read returns: - over 90% of the specified cache size
- 100% or more of the cache size.
PhixFlow reports an error and stops the analysis run when: - a single read returns 100% or more of the cache size
- and the System Configuration → Enforce Cache Size limit flag is ticked.
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| title | Error Message: Cache Size Limit Exceeded |
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| The Pipe "stream_name.lookup_pipe_name" cache is 100% full (the cache size is 10). |
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| Every time the lookup pipe is referenced, PhixFlow calculates the values of all of the variable elements of the query or pipe filter, and checks if it already has a set of data in the cache retrieved using this set of variable values. If so the data is immediately returned from the cache. Otherwise, a new set of data is read from the stream of collector. If adding the new records to the cache would cause it to exceed the maximum cache size, previously cached results are removed to make enough room for the new results. |
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| Buffer Size | Enter a number for the buffer size used to perform the stream calculation. If a large amount of data is being processed, then setting a large buffer size will give better performance. |
| Pipe View | Use this option to look up data from attributes that are present in a stream view on the input stream Select a stream view from the list. If the input stream has no views, the list will be empty. | Note |
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Sorting or filtering of records must be set directly on the pipe. It is not inherited from the pipe view. |
Use the pipe view to limit the attributes that the pipe reads when: - a stream has lots of attributes containing many data records
- but you only need data from a few attributes.
Only the data for the attributes in the stream view are sent to the output stream. Pipe views are very useful: - during lookups a pipe loads and caches all of the attributes from the stream. This can use a lot of memory, especially when there are many records.
- during file export all data records from all attributes are exported.
- Create a new view on the source stream. In the view, only add the attributes you need.
- In the pipe Pipe View option, select the pipe view.
- Run analysis. PhixFlow only looks-up or exports data from the attributes specified on the view.
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| title | Using pipe views with file exporters |
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| If a File Exporter is configured to export to Excel or to HTML: - and it has an Excel template, PhixFlow uses this template and does not use any template specified in the pipe view.
- but it does not have an Excel template, PhixFlow will use the Excel template specified in the pipe view (if there is one)
- and the pipe view is a chart view, PhixFlow will export a PNG picture of the chart.
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Max Records To Read
| Enter a number for the maximum number of records that should be read down this pipe. The pipe may read more than this number of records if it is configured to carry out multiple reads simultaneously. For example: - a pipe can be connected to a File Collector that reads multiple files simultaneously
- the pipe strategy is Directed with multiple workers.
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| Strategy | Select an option to specify how this pipe should be implemented. See the section on Directed Merge Strategy |
Max Workers | This field is available when Strategy is Directed Enter the maximum number of concurrent worker tasks. When no value is specified, this defaults to 1. |
| Worker Size | This field is available when Strategy is Directed Enter the number of key values to read for a single worker task, which runs a single select statement. When no value is specified, this defaults to 1000. This is the maximum value that can be used when reading from an Oracle database. |
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| From Offset | Enter the offset applied to the start of the collection period, relative to the period in the output stream that requires populating. |
| To Offset | Enter the offset applied to the end of the collection period, relative to the period in the output stream that requires populating. |
| Max Stream Sets | Enter the number of stream sets to be retrieved from the input stream. For a push pipe with positive offsets. enter the maximum number of stream sets that can be created i.e. the maximum number of cycles this pipe can initiate. |
| Only collect from same run | Every time the analysis engine runs, all of the stream sets that are created by all of the streams affected by that analysis run are given the same Run ID. | Insert excerpt |
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so the pipe can collect stream sets with different Run IDs. | Insert excerpt |
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so that the pipe will only collect stream sets from the input stream that have the same Run ID as the stream set currently being created by the output stream. You should only tick this checkbox check box if both the input and output streams have Period set to Transactional. |
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so that all data will be collected from the input stream, regardless of period. In this case, any From Offset or To Offset values determine whether the required data periods in the input stream exist before the stream calculation can be carried out. | Insert excerpt |
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so that the pipe will collect data from the input stream by period. For example, if: - the from and to offsets are both 0.0
- and the output stream requires stream generation for the period 17/10/07 - 18/10/07
the pipe reads data from the input stream for the period 17/10/07 - 18/10/07. |
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