Preventing cascade failures in computer systems

A computer program product for preventing a cascading failure in a complex stream computer system, wherein a cascading failure results in an untrustworthy output from the complex stream computer system, and wherein the computer program product comprises:

• a non-transitory computer readable storage medium;
• first program instructions to identify multiple subcomponents in a complex stream computer system, wherein the identified multiple subcomponents comprise multiple upstream subcomponents and a downstream subcomponent, and wherein the multiple upstream subcomponents execute upstream computational processes, wherein the multiple upstream subcomponents reside within a first computer hardware system, and wherein the downstream subcomponent resides within a second computer hardware system;
• second program instructions to identify multiple outputs generated by the multiple upstream subcomponents;
• third program instructions to identify multiple inputs to the downstream subcomponent, wherein the identified multiple inputs to the downstream subcomponent are the identified multiple outputs generated by the multiple upstream subcomponents, and wherein the identified multiple inputs are inputs to a downstream computational process that is executed by the downstream subcomponent;
• fourth program instructions to examine each of the upstream computational processes to determine an accuracy of each of the identified multiple outputs based upon:
• a source of inputs to each of the upstream computational processes;
• and
• a history of each of the upstream computational processes for producing predictions that exceed a predetermined level of accuracy;
• fifth program instructions to generate accuracy values by assigning an accuracy value to each of the identified multiple outputs, wherein the accuracy value describes a confidence level of an accuracy of each of the identified multiple outputs, and wherein each of the identified multiple outputs is created by a separate upstream computational process in separate upstream subcomponents from the multiple upstream subcomponents;
• sixth program instructions to generate weighting values by assigning a weighting value to each of the identified multiple inputs to the downstream subcomponent, wherein the weighting value describes a criticality level of each of the identified multiple inputs when executing the downstream computational process in the downstream subcomponent;
• seventh program instructions to utilize the accuracy values and the weighting values to dynamically adjust which of the identified multiple inputs are used by the downstream subcomponent in an effort to generate an output from the downstream subcomponent that meets a predefined trustworthiness level for making a first type of prediction, wherein a trustworthiness of the output from the downstream subcomponent is based on the accuracy value of each of the identified multiple outputs and the weighting value of each of the identified multiple inputs to the downstream subcomponent;
• eighth program instructions to determine that no variations of execution of one or more functions used by the downstream subcomponent ever produce an output that meets the predefined trustworthiness level for making the first type of prediction;
• and
• ninth program instructions to, in response to determining that no variations of execution of the one or more functions used by the downstream subcomponent ever produce the output that meets the predefined trustworthiness level for making the first type of prediction, execute a new downstream computational process that produces a different second type of prediction than that produced by the downstream subcomponent;
• and wherein
• the first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth program instructions are stored on the non-transitory computer readable storage medium.

A system comprising:

• a hardware processor, a computer readable memory, and a non-transitory computer readable storage medium;
• first program instructions to identify multiple subcomponents in a complex stream computer system, wherein the identified multiple subcomponents comprise multiple upstream subcomponents and a downstream subcomponent, and wherein the multiple upstream subcomponents execute upstream computational processes, wherein the multiple upstream subcomponents reside within a first computer hardware system, and wherein the downstream subcomponent resides within a second computer hardware system;
• second program instructions to identify multiple outputs generated by the multiple upstream subcomponents;
• third program instructions to identify multiple inputs to the downstream subcomponent, wherein the identified multiple inputs to the downstream subcomponent are the identified multiple outputs generated by the multiple upstream subcomponents, and wherein the identified multiple inputs are inputs to a downstream computational process that is executed by the downstream subcomponent;
• fourth program instructions to examine each of the upstream computational processes to determine an accuracy of each of the identified multiple outputs based upon:
• a source of inputs to each of the upstream computational processes;
• and
• a history of each of the upstream computational processes for producing predictions that exceed a predetermined level of accuracy;
• fifth program instructions to generate accuracy values by assigning an accuracy value to each of the identified multiple outputs, wherein the accuracy value describes a confidence level of an accuracy of each of the identified multiple outputs, and wherein each of the identified multiple outputs is created by a separate upstream computational process in separate upstream subcomponents from the multiple upstream subcomponents;
• sixth program instructions to generate weighting values by assigning a weighting value to each of the identified multiple inputs to the downstream subcomponent, wherein the weighting value describes a criticality level of each of the identified multiple inputs when executing the downstream computational process in the downstream subcomponent;
• seventh program instructions to utilize the accuracy values and the weighting values to dynamically adjust which of the identified multiple inputs are used by the downstream subcomponent in an effort to generate an output from the downstream subcomponent that meets a predefined trustworthiness level for making a first type of prediction, wherein a trustworthiness of the output from the downstream subcomponent is based on the accuracy value of each of the identified multiple outputs and the weighting value of each of the identified multiple inputs to the downstream subcomponent;
• eighth program instructions to determine that no variations of execution of one or more functions used by the downstream subcomponent ever produce an output that meets the predefined trustworthiness level for making the first type of prediction;
• and
• ninth program instructions to, in response to determining that no variations of execution of the one or more functions used by the downstream subcomponent ever produce the output that meets the predefined trustworthiness level for making the first type of prediction, execute a new downstream computational process that produces a different second type of prediction than that produced by the downstream subcomponent;
• and wherein
• the first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth program instructions are stored on the non-transitory computer readable storage medium for execution by the hardware processor via the computer readable memory.