1. An apparatus for efficiently mining a control flow graph from execution logs of a distributed system, said apparatus comprising: at least one processor; and a computer readable storage medium having computer readable program code embodied therewith and executable by the at least one processor, the computer readable program code comprising: computer readable program code that receives a plurality of execution logs; computer readable program code that mines at least one template from the plurality of execution logs in a first-phase, wherein the mining comprises computer readable program code that creates at least one template via a two-stage template mining technique, comprising: a first stage of the two-stage template mining technique comprising computer readable program code that creates approximate-templates via a dictionary based logline transformation in order to attain scalability; and a second second-stage of the two-stage template mining technique comprising computer readable program code that refines the mined approximate-templates by leveraging the multimodal (text+temporal-vicinity) signature of each approximate-template; and computer readable program code that generates the control-flow graph between the mined templates in a second phase via a two-stage technique comprising: a first-stage of the second phase comprising computer readable program code that creates, for each template, a set of the template's temporally co-occurring templates via leveraging a time-series of occurrence of each template; and a second-stage of the second phase comprising computer readable program code that determines, in a single-pass of the log stream for each template, the template's immediate predecessors/successor on the temporally co-occurring templates and computer readable program code that stitches mined successors of each template to construct the control flow graph.