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[4] Amr El-Helw et al: Optimization of Common Table Expressions in MPP Database Systems. PVLDB 8(12): 1704-1715 (2015)
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Apache HAWQ is an effort undergoing incubation at The Apache Software Foundation (ASF), sponsored by the Incubator. Incubation is required of all newly accepted projects until a further review indicates that the infrastructure, communications, and decision making process have stabilized in a manner consistent with other successful ASF projects. While incubation status is not necessarily a reflection of the completeness or stability of the code, it does indicate that the project has yet to be fully endorsed by the ASF.