Parallel jobs on Windows fail with APT_IOPort::readBlkVirt;error

APT_IOPort::readBlkVirt Error Screenshot
APT_IOPort::readBlkVirt Error Screenshot

This a known error for windows systems and applies to DataStage and DataQuality jobs using the any or all the three join type stages (Join, Merge, and Lookup).

Error Message

  • <<Link name>>,0: APT_IOPort::readBlkVirt: read for block header, partition 0, [fd 4], returned -1 with errno 10,054 (Unknown error)

Message ID

  • IIS-DSEE-TFIO-00223

Applies To

  • Windows systems only
  • Parallel Engine Jobs the three join type stages (Join, Merge, and Lookup). It does not apply to Server Engine jobs.
  • Infosphere Information Server (IIS), Datastage and DataQuality 9.1 and higher

The Fix

  • Add the APT_NO_IOCOMM_OPTIMIZATION in project administrator and set to blank or 0. I left it blank so it would not impact other jobs
  • Add the environment variable to the job producing the error and set to 1

What it APT_NO_IOCOMM_OPTIMIZATION Does

  • Sets the use of shared memory as the transport type, rather than using the default sockets transport type.
  • Note that in most cases sockets transport type is faster, so, you likely will not to set this across the project as the default for all job. It is best to apply it as necessary for problematic jobs.

Related References

InfoSphere DataStage and QualityStage, Version 9.1 Job Compatibility

IBM Support, JR54078: PARALLEL JOBS ON WINDOWS FAIL WITH APT_IOPORT::READBLKVIRT; ERROR

IBM Support, Information Server DataStage job fails with unknown error 10,054.

 

Data Modeling – Fact Table Effective Practices

Database Table
Database Table

Here are a few guidelines for modeling and designing fact tables.

Fact Table Effective Practices

  • The table naming convention should identify it as a fact table. For example:
    • Suffix Pattern:
      • <<TableName>>_Fact
      • <<TableName>>_F
    • Prefix Pattern:
      • FACT_<TableName>>
      • F_<TableName>>
    • Must contain a temporal dimension surrogate key (e.g. date dimension)
    • Measures should be nullable – this has an impact on aggregate functions (SUM, COUNT, MIN, MAX, and AVG, etc.)
    • Dimension Surrogate keys (srky) should have a foreign key (FK) constraint
    • Do not place the dimension processing in the fact jobs

Related References

Data Modeling – Dimension Table Effective Practices

Database Table
Database Table

I’ve had these notes laying around for a while, so, I thought I consolidate them here.   So, here are few guidelines to ensure the quality of your dimension table structures.

Dimension Table Effective Practices

  • The table naming convention should identify it as a dimension table. For example:
    • Suffix Pattern:
      • <<TableName>>_Dim
      • <<TableName>>_D
    • Prefix Pattern:
      • Dim_<TableName>>
      • D_<TableName>>
  • Have Primary Key (PK) assigned on table surrogate Key
  • Audit fields – Type 1 dimensions should:
    • Have a Created Date timestamp – When the record was initially created
    • have a Last Update Timestamp – When was the record last updated
  • Job Flow: Do not place the dimension processing in the fact jobs.
  • Every Dimension should have a Zero (0), Unknown, row
  • Fields should be ‘NOT NULL’ replacing nulls with a zero (0) numeric and integer type fields or space ( ‘ ‘ ) for Character type files.
  • Keep dimension processing outside of the fact jobs

Related References

Infosphere DataStage – Boolean Handling for Netezza

Datastage Director Message - Numeric string expected
Datastage Director Message – Numeric string expected

 

Beware when you see this message when working with Boolean in DataStage, the message displays as informational (at list it did for me) not as a warning or an error.  Even though it seems innocuous, what it meant for my job, was the Boolean (‘true’ / ‘false’) was not being interpreted and everything posted to ‘false’.

In DataStage the Netezza ‘Boolean’ field/Data SQL type maps to the ‘Bit’ SQL type, which expects a numeric input of Zero (0) or one (1).  So, my solution (once I detected the problem during unit testing) was to put Transformer Stage logic in place to convert the Boolean input to the expected number value.

 

Netezza to Datastage Data Type Mapping

Netezza data types

InfoSphere DataStage

data types (SQL types)

Expected Input value

BOOLEAN Bit 0 or 1 (1 = true, 0 = false)

 

Transformer Stage logic Boolean Handling Logic

A Netezza Boolean field can store: true values, false values, and null. So, some thought should be given to you desired data outcome for nulls

This first example sets a that the nulls are set to a specific value, which can support a specific business rule for null handling and, also, provide null handling for non-nullable fields.  Here we are setting nulls to the numeric value for ‘true’ and all other non-true inputs to ‘false’.

If isnull(Lnk_Src_In.USER_ACTIVE) then 1 Else if Lnk_Src_In.USER_ACTIVE = ‘true’ Then 1 Else 0

These second examples sets a that the nulls are set by the Else value, if your logic direction is correct value and still provides null handling for non-nullable fields.

  • If  Lnk_Src_In.USER_ACTIVE = ‘true’ Then 1 Else 0

  • If  Lnk_Src_In.USER_ACTIVE = ‘False’ Then 0 Else 1

Director Log Message

Message ID

  • IIS-DSEE-TBLD-00008

Message Text

  • <<Link Name Where Message Occurred>>: Numeric string expected. Use default value.

Or something like this:

  • <<Link Name Where Message Occurred>>: Numeric string expected for input column ‘<<Field Name Here>>‘. Use default value.

Related References

Boolean

PureData System for Analytics, PureData System for Analytics 7.2.1, IBM Netezza user-defined functions, UDX data types reference information, Supported data types, Boolean

https://www.ibm.com/support/knowledgecenter/en/SSULQD_7.2.1/com.ibm.nz.udf.doc/r_udf_boolean_datatype.html

Data types and aliases

PureData System for Analytics, PureData System for Analytics 7.2.1, IBM Netezza stored procedures, NZPLSQL statements and grammar, Variables and constants, Data types and aliases

https://www.ibm.com/support/knowledgecenter/en/SSULQD_7.2.1/com.ibm.nz.sproc.doc/c_sproc_data_types_aliases.html

Logical data types

PureData System for Analytics, PureData System for Analytics 7.2.1, IBM Netezza database user documentation, Netezza SQL basics, Data types, Logical data types

https://www.ibm.com/support/knowledgecenter/en/SSULQD_7.2.1/com.ibm.nz.dbu.doc/r_dbuser_data_types_logical.html

Data type conversions from Netezza to DataStage

InfoSphere Information Server, InfoSphere Information Server 11.5.0, Connecting to data sources, Databases, Netezza Performance Server, Netezza connector, Designing jobs by using the Netezza connector, Defining a Netezza connector job, Data type conversions, Data type conversions from Netezza to DataStage

https://www.ibm.com/support/knowledgecenter/en/SSZJPZ_11.5.0/com.ibm.swg.im.iis.conn.netezza.use.doc/topics/nzcc_mappingdatatypes.html