In this paper, we completely characterize the compactness of the Volterra type integration operators Jb acting from weighted Bergman spaces Apa to Hardy spaces Hq for all 0 < p; q < 1. Furthermore, we give some estimates for the essential norms of Jb : Apa -> Hq in the case 0 < p < q < 1. We finally describe the membership in the Schatten(-Herz) class of the Volterra type integration operators.