Allow null keys in Spark's reduce and group by
Allow null keys in Spark's reduce and group by

joseph-torres/spark,wangmiao1981/spark,akopich/spark,zhouyejoe/spark,JerryLead/spark,brad-kaiser/spark,alunarbeach/spark,mike0sv/spark,publicRoman/spark,adrian-ionescu/apache-spark,brad-kaiser/spark,bravo-zhang/spark,liyichao/spark,rikima/spark,eyalfa/spark,mdespriee/spark,guoxiaolongzte/spark,ptkool/spark,aray/spark,srowen/spark,kevinyu98/spark,akopich/spark,someorz/spark,publicRoman/spark,taroplus/spark,panfengfeng/spark,poffuomo/spark,michalsenkyr/spark,bdrillard/spark,markhamstra/spark,apache-spark-on-k8s/spark,wzhfy/spark,map222/spark,ericvandenbergfb/spark,panfengfeng/spark,BryanCutler/spark,alunarbeach/spark,lvdongr/spark,panfengfeng/spark,mdespriee/spark,sahilTakiar/spark,mzl9039/spark,ericvandenbergfb/spark,andrewor14/spark,techaddict/spark,pgandhi999/spark,debugger87/spark,rjpower/spark,adrian-ionescu/apache-spark,highfei2011/spark,setjet/spark,poffuomo/spark,facaiy/spark,WindCanDie/spark,icexelloss/spark,ron8hu/spark,cloudera/spark,apache-spark-on-k8s/spark,cloud-fan/spark,ankurdave/arthur,szhem/spark,markhamstra/spark,dongjoon-hyun/spark,liutang123/spark,lxsmnv/spark,actuaryzhang/spark,jianran/spark,nilsgrabbert/spark,witgo/spark,ddna1021/spark,milliman/spark,minixalpha/spark,maropu/spark,mzl9039/spark,zero323/spark,goldmedal/spark,kissmetrics/spark,nchammas/spark,apache-spark-on-k8s/spark,ahnqirage/spark,koeninger/spark,ddna1021/spark,jianran/spark,loneknightpy/spark,ibm-research-ireland/sparkoscope,taroplus/spark,ptkool/spark,akopich/spark,szhem/spark,zhouyejoe/spark,rikima/spark,stanzhai/spark,matthewfranglen/spark,saltstar/spark,ron8hu/spark,andrewor14/iolap,jiangxb1987/spark,debugger87/spark,jkbradley/spark,xuanyuanking/spark,chuckchen/spark,jiangxb1987/spark,shuangshuangwang/spark,UndeadBaneGitHub/spark,ptkool/spark,setjet/spark,someorz/spark,setjet/spark,chuckchen/spark,vax11780/spark,dbtsai/spark,ptkool/spark,jrshust/spark,caneGuy/spark,pronix/spark,ron8hu/spark,maropu/spark,alunarbeach/spark,jlopezmalla/spark,highfei2011/spark,1haodian/spark,yanboliang/spark,zzcclp/spark,apache-spark-on-k8s/spark,pronix/spark,caneGuy/spark,ioana-delaney/spark,zero323/spark,haowu80s/spark,apache-spark-on-k8s/spark,sureshthalamati/spark,zuotingbing/spark,stanzhai/spark,lvdongr/spark,jkbradley/spark,saturday-shi/spark,highfei2011/spark,kissmetrics/spark,JoshRosen/spark,jrshust/spark,Panos-Bletsos/spark-cost-model-optimizer,icexelloss/spark,wzhfy/spark,Panos-Bletsos/spark-cost-model-optimizer,dbtsai/spark,wgpshashank/spark,map222/spark,sureshthalamati/spark,guoxiaolongzte/spark,skonto/spark,bravo-zhang/spark,stanzhai/spark,UndeadBaneGitHub/spark,jkbradley/spark,ibm-research-ireland/sparkoscope,ioana-delaney/spark,zzcclp/spark,bravo-zhang/spark,narahari92/spark,aokolnychyi/spark,WindCanDie/spark,setjet/spark,metamx/spark,yanboliang/spark,huang1900/spark,vinodkc/spark,SnappyDataInc/spark,dhruve/spark,tengpeng/spark,bdrillard/spark,shaneknapp/spark,bravo-zhang/spark,andrewor14/spark,zhouyejoe/spark,liyichao/spark,skonto/spark,lxsmnv/spark,UndeadBaneGitHub/spark,Aegeaner/spark,metamx/spark,aokolnychyi/spark,dotunolafunmiloye/spark,jlopezmalla/spark,mike0sv/spark,ericvandenbergfb/spark,big-pegasus/spark,Panos-Bletsos/spark-cost-model-optimizer,loneknightpy/spark,1haodian/spark,jlopezmalla/spark,poffuomo/spark,sryza/spark,maropu/spark,map222/spark,SHASHANKB/spark,icexelloss/spark,hhbyyh/spark,esi-mineset/spark,shaneknapp/spark,vinodkc/spark,dongjoon-hyun/spark,debugger87/spark,alunarbeach/spark,rezasafi/spark,milliman/spark,mzl9039/spark,tejasapatil/spark,ddna1021/spark,ueshin/apache-spark,Aegeaner/spark,tengpeng/spark,apache/spark,loneknightpy/spark,chuckchen/spark,WindCanDie/spark,tengpeng/spark,mike0sv/spark,zzcclp/spark,shubhamchopra/spark,narahari92/spark,dhruve/spark,eyalfa/spark,sryza/spark,bravo-zhang/spark,darionyaphet/spark,SHASHANKB/spark,koeninger/spark,JoshRosen/spark,saltstar/spark,zzcclp/spark,jianran/spark,brad-kaiser/spark,kiszk/spark,xflin/spark,caneGuy/spark,poffuomo/spark,metamx/spark,WeichenXu123/spark,ueshin/apache-spark,sahilTakiar/spark,rezasafi/spark,dotunolafunmiloye/spark,andrewor14/spark,dbtsai/spark,dhruve/spark,tejasapatil/spark,shaneknapp/spark,nilsgrabbert/spark,ron8hu/spark,sryza/spark,actuaryzhang/spark,sachintyagi22/spark,markhamstra/spark,techaddict/spark,ron8hu/spark,brad-kaiser/spark,highfei2011/spark,nilsgrabbert/spark,michalsenkyr/spark,ankurdave/arthur,kevinyu98/spark,lyogavin/spark,sachintyagi22/spark,rikima/spark,sachintyagi22/spark,zero323/spark,ioana-delaney/spark,markhamstra/spark,LantaoJin/spark,publicRoman/spark,rednaxelafx/apache-spark,maropu/spark,hhbyyh/spark,Aegeaner/spark,saturday-shi/spark,patrick-nicholson/spark,rezasafi/spark,aosagie/spark,sureshthalamati/spark,holdenk/spark,jrshust/spark,rjpower/spark,markhamstra/spark,byakuinss/spark,tejasapatil/spark,sachintyagi22/spark,eyalfa/spark,janewangfb/spark,kissmetrics/spark,Aegeaner/spark,rjpower/spark,chuckchen/spark,stanzhai/spark,zhouyejoe/spark,HyukjinKwon/spark,big-pegasus/spark,mahak/spark,LantaoJin/spark,map222/spark,kevinyu98/spark,michalsenkyr/spark,jiangxb1987/spark,shuangshuangwang/spark,dhruve/spark,gioenn/xSpark,SHASHANKB/spark,UndeadBaneGitHub/spark,BryanCutler/spark,WeichenXu123/spark,esi-mineset/spark,huang1900/spark,wangmiao1981/spark,facaiy/spark,zuotingbing/spark,rekhajoshm/spark,holdenk/spark,andrewor14/spark,zero323/spark,guoxiaolongzte/spark,ueshin/apache-spark,BryanCutler/spark,aray/spark,markhamstra/spark,WeichenXu123/spark,tejasapatil/spark,mike0sv/spark,cloud-fan/spark,mike0sv/spark,caneGuy/spark,MLnick/spark,lvdongr/spark,holdenk/spark,jiangxb1987/spark,big-pegasus/spark,eyalfa/spark,shubhamchopra/spark,lxsmnv/spark,andrewor14/iolap,debugger87/spark,nchammas/spark,vinodkc/spark,zero323/spark,sahilTakiar/spark,yanboliang/spark,aray/spark,milliman/spark,rekhajoshm/spark,stanzhai/spark,panfengfeng/spark,wgpshashank/spark,janewangfb/spark,jkbradley/spark,apache/spark,sachintyagi22/spark,HyukjinKwon/spark,andrewor14/spark,1haodian/spark,zuotingbing/spark,minixalpha/spark,adrian-ionescu/apache-spark,dongjoon-hyun/spark,Panos-Bletsos/spark-cost-model-optimizer,ibm-research-ireland/sparkoscope,Panos-Bletsos/spark-cost-model-optimizer,cin/spark,HyukjinKwon/spark,michalsenkyr/spark,actuaryzhang/spark,jkbradley/spark,sachintyagi22/spark,gioenn/xSpark,szhem/spark,sachintyagi22/spark,BryanCutler/spark,haowu80s/spark,ajaysaini725/spark,wangyum/spark,caneGuy/spark,WeichenXu123/spark,goldmedal/spark,zuotingbing/spark,mahak/spark,sahilTakiar/spark,mahak/spark,facaiy/spark,xuanyuanking/spark,lyogavin/spark,alunarbeach/spark,big-pegasus/spark,byakuinss/spark,spark-test/spark,JerryLead/spark,guoxiaolongzte/spark,MLnick/spark,nilsgrabbert/spark,szhem/spark,akopich/spark,jiangxb1987/spark,tejasapatil/spark,poffuomo/spark,vinodkc/spark,saltstar/spark,rezasafi/spark,cloud-fan/spark,bOOm-X/spark,techaddict/spark,kiszk/spark,patrick-nicholson/spark,huang1900/spark,ahnqirage/spark,xuanyuanking/spark,sahilTakiar/spark,lyogavin/spark,dbtsai/spark,jlopezmalla/spark,SHASHANKB/spark,dbtsai/spark,ioana-delaney/spark,ajaysaini725/spark,kimoonkim/spark,techaddict/spark,someorz/spark,SnappyDataInc/spark,dbtsai/spark,maropu/spark,goldmedal/spark,hhbyyh/spark,michalsenkyr/spark,rikima/spark,sureshthalamati/spark,hvanhovell/spark,LantaoJin/spark,akopich/spark,1haodian/spark,bOOm-X/spark,dbtsai/spark,SnappyDataInc/spark,rednaxelafx/apache-spark,jianran/spark,shubhamchopra/spark,liutang123/spark,ptkool/spark,joseph-torres/spark,esi-mineset/spark,aosagie/spark,jlopezmalla/spark,HyukjinKwon/spark,aosagie/spark,byakuinss/spark,ajaysaini725/spark,zuotingbing/spark,narahari92/spark,actuaryzhang/spark,big-pegasus/spark,kimoonkim/spark,shuangshuangwang/spark,sahilTakiar/spark,ibm-research-ireland/sparkoscope,mzl9039/spark,MLnick/spark,nchammas/spark,wangmiao1981/spark,rednaxelafx/apache-spark,aray/spark,goldmedal/spark,publicRoman/spark,poffuomo/spark,shaneknapp/spark,kiszk/spark,cin/spark,taroplus/spark,joseph-torres/spark,minixalpha/spark,andrewor14/spark,haowu80s/spark,liyichao/spark,pgandhi999/spark,aray/spark,guoxiaolongzte/spark,kissmetrics/spark,mahak/spark,byakuinss/spark,ddna1021/spark,setjet/spark,dongjoon-hyun/spark,apache/spark,hvanhovell/spark,patrick-nicholson/spark,LantaoJin/spark,saltstar/spark,mike0sv/spark,actuaryzhang/spark,spark-test/spark,janewangfb/spark,rednaxelafx/apache-spark,liyichao/spark,wangyum/spark,spark-test/spark,mdespriee/spark,janewangfb/spark,taroplus/spark,JoshRosen/spark,cloud-fan/spark,dotunolafunmiloye/spark,cloud-fan/spark,ahnqirage/spark,ddna1021/spark,wangmiao1981/spark,pgandhi999/spark,markhamstra/spark,lvdongr/spark,shuangshuangwang/spark,sureshthalamati/spark,pronix/spark,rekhajoshm/spark,sureshthalamati/spark,shaneknapp/spark,HyukjinKwon/spark,ron8hu/spark,joseph-torres/spark,byakuinss/spark,chuckchen/spark,wangyum/spark,setjet/spark,vax11780/spark,WeichenXu123/spark,rikima/spark,jlopezmalla/spark,skonto/spark,skonto/spark,goldmedal/spark,kevinyu98/spark,lxsmnv/spark,jrshust/spark,rekhajoshm/spark,ericvandenbergfb/spark,vax11780/spark,rednaxelafx/apache-spark,cloudera/spark,brad-kaiser/spark,maropu/spark,sryza/spark,tejasapatil/spark,mdespriee/spark,stanzhai/spark,gioenn/xSpark,apache-spark-on-k8s/spark,aosagie/spark,tengpeng/spark,andrewor14/iolap,SnappyDataInc/spark,saltstar/spark,srowen/spark,huang1900/spark,techaddict/spark,Aegeaner/spark,bdrillard/spark,wangyum/spark,haowu80s/spark,ConeyLiu/spark,lyogavin/spark,lxsmnv/spark,BryanCutler/spark,ajaysaini725/spark,byakuinss/spark,zhouyejoe/spark,zuotingbing/spark,facaiy/spark,ueshin/apache-spark,skonto/spark,aokolnychyi/spark,mdespriee/spark,tengpeng/spark,someorz/spark,caneGuy/spark,hvanhovell/spark,aray/spark,szhem/spark,wzhfy/spark,alunarbeach/spark,darionyaphet/spark,taroplus/spark,bravo-zhang/spark,yanboliang/spark,xflin/spark,rezasafi/spark,mkolod/incubator-spark,big-pegasus/spark,ajaysaini725/spark,xflin/spark,rikima/spark,huang1900/spark,actuaryzhang/spark,wzhfy/spark,rikima/spark,BryanCutler/spark,mzl9039/spark,kissmetrics/spark,nilsgrabbert/spark,jrshust/spark,ibm-research-ireland/sparkoscope,techaddict/spark,gioenn/xSpark,gengliangwang/spark,jianran/spark,cin/spark,icexelloss/spark,saturday-shi/spark,pgandhi999/spark,mzl9039/spark,tengpeng/spark,1haodian/spark,bdrillard/spark,tejasapatil/spark,minixalpha/spark,hvanhovell/spark,vinodkc/spark,panfengfeng/spark,ajaysaini725/spark,panfengfeng/spark,bOOm-X/spark,ConeyLiu/spark,xflin/spark,bOOm-X/spark,yanboliang/spark,adrian-ionescu/apache-spark,nlalevee/spark,skonto/spark,darionyaphet/spark,joseph-torres/spark,shuangshuangwang/spark,WindCanDie/spark,metamx/spark,wzhfy/spark,dhruve/spark,bOOm-X/spark,narahari92/spark,patrick-nicholson/spark,mkolod/incubator-spark,nilsgrabbert/spark,cloud-fan/spark,ioana-delaney/spark,minixalpha/spark,loneknightpy/spark,lxsmnv/spark,ueshin/apache-spark,wzhfy/spark,janewangfb/spark,poffuomo/spark,ConeyLiu/spark,debugger87/spark,kimoonkim/spark,zhouyejoe/spark,setjet/spark,JerryLead/spark,huang1900/spark,dhruve/spark,gioenn/xSpark,saturday-shi/spark,cloud-fan/spark,shubhamchopra/spark,ahnqirage/spark,pgandhi999/spark,kevinyu98/spark,Panos-Bletsos/spark-cost-model-optimizer,zero323/spark,liyichao/spark,lvdongr/spark,kissmetrics/spark,pgandhi999/spark,dongjoon-hyun/spark,map222/spark,ankurdave/arthur,sahilTakiar/spark,xflin/spark,ConeyLiu/spark,witgo/spark,ahnqirage/spark,WindCanDie/spark,nlalevee/spark,debugger87/spark,ajaysaini725/spark,patrick-nicholson/spark,UndeadBaneGitHub/spark,adrian-ionescu/apache-spark,icexelloss/spark,LantaoJin/spark,minixalpha/spark,rednaxelafx/apache-spark,huang1900/spark,mike0sv/spark,saturday-shi/spark,MLnick/spark,cloudera/spark,yanboliang/spark,witgo/spark,nlalevee/spark,aokolnychyi/spark,liutang123/spark,mahak/spark,techaddict/spark,spark-test/spark,zzcclp/spark,cin/spark,holdenk/spark,minixalpha/spark,apache/spark,gengliangwang/spark,metamx/spark,rezasafi/spark,pronix/spark,jlopezmalla/spark,jiangxb1987/spark,jianran/spark,SHASHANKB/spark,SnappyDataInc/spark,ahnqirage/spark,holdenk/spark,saltstar/spark,lvdongr/spark,kevinyu98/spark,kimoonkim/spark,patrick-nicholson/spark,spark-test/spark,mkolod/incubator-spark,gengliangwang/spark,ioana-delaney/spark,joseph-torres/spark,milliman/spark,JoshRosen/spark,apache/spark,koeninger/spark,zuotingbing/spark,aokolnychyi/spark,vinodkc/spark,dongjoon-hyun/spark,UndeadBaneGitHub/spark,xuanyuanking/spark,SnappyDataInc/spark,wangyum/spark,map222/spark,patrick-nicholson/spark,JerryLead/spark,shuangshuangwang/spark,aosagie/spark,facaiy/spark,pronix/spark,wzhfy/spark,gengliangwang/spark,liutang123/spark,Aegeaner/spark,eyalfa/spark,MLnick/spark,darionyaphet/spark,SHASHANKB/spark,WeichenXu123/spark,kiszk/spark,kevinyu98/spark,icexelloss/spark,nchammas/spark,1haodian/spark,adrian-ionescu/apache-spark,bdrillard/spark,liyichao/spark,highfei2011/spark,holdenk/spark,kiszk/spark,ericvandenbergfb/spark,xflin/spark,highfei2011/spark,someorz/spark,guoxiaolongzte/spark,bdrillard/spark,hvanhovell/spark,srowen/spark,cin/spark,ddna1021/spark,publicRoman/spark,kimoonkim/spark,saltstar/spark,andrewor14/iolap,esi-mineset/spark,zzcclp/spark,UndeadBaneGitHub/spark,BryanCutler/spark,JerryLead/spark,mdespriee/spark,nlalevee/spark,jianran/spark,cin/spark,rekhajoshm/spark,jkbradley/spark,ahnqirage/spark,map222/spark,liutang123/spark,SHASHANKB/spark,milliman/spark,Panos-Bletsos/spark-cost-model-optimizer,someorz/spark,ueshin/apache-spark,akopich/spark,ConeyLiu/spark,aray/spark,HyukjinKwon/spark,srowen/spark,srowen/spark,kimoonkim/spark,nlalevee/spark,hhbyyh/spark,guoxiaolongzte/spark,gengliangwang/spark,mkolod/incubator-spark,gengliangwang/spark,narahari92/spark,hvanhovell/spark,wangmiao1981/spark,byakuinss/spark,witgo/spark,WindCanDie/spark,narahari92/spark,nilsgrabbert/spark,akopich/spark,witgo/spark,JerryLead/spark,MLnick/spark,pronix/spark,cloudera/spark,ConeyLiu/spark,adrian-ionescu/apache-spark,panfengfeng/spark,JoshRosen/spark,zero323/spark,SnappyDataInc/spark,gioenn/xSpark,cloudera/spark,vax11780/spark,1haodian/spark,andrewor14/spark,jrshust/spark,darionyaphet/spark,kiszk/spark,esi-mineset/spark,rezasafi/spark,bOOm-X/spark,rednaxelafx/apache-spark,metamx/spark,gioenn/xSpark,brad-kaiser/spark,rekhajoshm/spark,jkbradley/spark,andrewor14/iolap,liutang123/spark,bravo-zhang/spark,goldmedal/spark,publicRoman/spark,hhbyyh/spark,shubhamchopra/spark,Aegeaner/spark,witgo/spark,lyogavin/spark,spark-test/spark,chuckchen/spark,liutang123/spark,loneknightpy/spark,ericvandenbergfb/spark,dhruve/spark,ankurdave/arthur,cin/spark,mdespriee/spark,aokolnychyi/spark,ConeyLiu/spark,ptkool/spark,narahari92/spark,andrewor14/iolap,ericvandenbergfb/spark,nchammas/spark,apache/spark,wangmiao1981/spark,jiangxb1987/spark,shubhamchopra/spark,haowu80s/spark,lxsmnv/spark,metamx/spark,shuangshuangwang/spark,loneknightpy/spark,wangmiao1981/spark,alunarbeach/spark,debugger87/spark,stanzhai/spark,zzcclp/spark,kimoonkim/spark,koeninger/spark,rjpower/spark,michalsenkyr/spark,darionyaphet/spark,JoshRosen/spark,xuanyuanking/spark,mahak/spark,goldmedal/spark,xflin/spark,apache-spark-on-k8s/spark,zhouyejoe/spark,brad-kaiser/spark,nlalevee/spark,janewangfb/spark,maropu/spark,ibm-research-ireland/sparkoscope,taroplus/spark,hvanhovell/spark,ibm-research-ireland/sparkoscope,publicRoman/spark,joseph-torres/spark,xuanyuanking/spark,vinodkc/spark,big-pegasus/spark,nchammas/spark,HyukjinKwon/spark,facaiy/spark,hhbyyh/spark,dotunolafunmiloye/spark,michalsenkyr/spark,kiszk/spark,esi-mineset/spark,sureshthalamati/spark,eyalfa/spark,saturday-shi/spark,tengpeng/spark,esi-mineset/spark,highfei2011/spark,icexelloss/spark,wangyum/spark,wgpshashank/spark,vax11780/spark,mkolod/incubator-spark,someorz/spark,mzl9039/spark,kissmetrics/spark,aosagie/spark,actuaryzhang/spark,ueshin/apache-spark,xuanyuanking/spark,darionyaphet/spark,nchammas/spark,srowen/spark,rjpower/spark,aosagie/spark,gengliangwang/spark,holdenk/spark,liyichao/spark,bOOm-X/spark,lvdongr/spark,mahak/spark,srowen/spark,LantaoJin/spark,bdrillard/spark,nlalevee/spark,saturday-shi/spark,LantaoJin/spark,sryza/spark,chuckchen/spark,pgandhi999/spark,ptkool/spark,wangyum/spark,JoshRosen/spark,shaneknapp/spark,ron8hu/spark,WindCanDie/spark,loneknightpy/spark,aokolnychyi/spark,haowu80s/spark,yanboliang/spark,spark-test/spark,apache/spark,eyalfa/spark,dongjoon-hyun/spark,WeichenXu123/spark,MLnick/spark,jrshust/spark,JerryLead/spark,shaneknapp/spark,milliman/spark,andrewor14/iolap,skonto/spark,janewangfb/spark,facaiy/spark,szhem/spark,rekhajoshm/spark,ioana-delaney/spark,shubhamchopra/spark,hhbyyh/spark,ddna1021/spark,szhem/spark,taroplus/spark,milliman/spark,caneGuy/spark,koeninger/spark,witgo/spark,wgpshashank/spark