Add description of log_statement_stats's function (total statement stats rather than per-stage stats).
Add description of log_statement_stats's function (total statement stats
rather than per-stage stats).

atris/gpdb,tangp3/gpdb,Quikling/gpdb,yazun/postgres-xl,ashwinstar/gpdb,rvs/gpdb,arcivanov/postgres-xl,0x0FFF/gpdb,rvs/gpdb,lpetrov-pivotal/gpdb,edespino/gpdb,ahachete/gpdb,snaga/postgres-xl,yuanzhao/gpdb,50wu/gpdb,lpetrov-pivotal/gpdb,zaksoup/gpdb,rvs/gpdb,greenplum-db/gpdb,rubikloud/gpdb,50wu/gpdb,xuegang/gpdb,chrishajas/gpdb,adam8157/gpdb,kaknikhil/gpdb,tangp3/gpdb,janebeckman/gpdb,cjcjameson/gpdb,greenplum-db/gpdb,tpostgres-projects/tPostgres,CraigHarris/gpdb,techdragon/Postgres-XL,zeroae/postgres-xl,jmcatamney/gpdb,randomtask1155/gpdb,kaknikhil/gpdb,Chibin/gpdb,kaknikhil/gpdb,lisakowen/gpdb,chrishajas/gpdb,rubikloud/gpdb,zaksoup/gpdb,zeroae/postgres-xl,Chibin/gpdb,edespino/gpdb,chrishajas/gpdb,ashwinstar/gpdb,janebeckman/gpdb,oberstet/postgres-xl,Postgres-XL/Postgres-XL,xinzweb/gpdb,0x0FFF/gpdb,royc1/gpdb,xinzweb/gpdb,adam8157/gpdb,greenplum-db/gpdb,royc1/gpdb,edespino/gpdb,lpetrov-pivotal/gpdb,rubikloud/gpdb,foyzur/gpdb,Quikling/gpdb,50wu/gpdb,cjcjameson/gpdb,randomtask1155/gpdb,zaksoup/gpdb,0x0FFF/gpdb,jmcatamney/gpdb,rvs/gpdb,tpostgres-projects/tPostgres,Chibin/gpdb,edespino/gpdb,royc1/gpdb,xuegang/gpdb,yuanzhao/gpdb,CraigHarris/gpdb,rvs/gpdb,foyzur/gpdb,rubikloud/gpdb,foyzur/gpdb,ovr/postgres-xl,Quikling/gpdb,arcivanov/postgres-xl,adam8157/gpdb,lpetrov-pivotal/gpdb,yazun/postgres-xl,xuegang/gpdb,pavanvd/postgres-xl,arcivanov/postgres-xl,0x0FFF/gpdb,chrishajas/gpdb,ovr/postgres-xl,ovr/postgres-xl,greenplum-db/gpdb,royc1/gpdb,royc1/gpdb,kmjungersen/PostgresXL,pavanvd/postgres-xl,techdragon/Postgres-XL,tangp3/gpdb,janebeckman/gpdb,ashwinstar/gpdb,lintzc/gpdb,xinzweb/gpdb,adam8157/gpdb,kaknikhil/gpdb,chrishajas/gpdb,zeroae/postgres-xl,lisakowen/gpdb,kaknikhil/gpdb,atris/gpdb,cjcjameson/gpdb,ahachete/gpdb,xuegang/gpdb,ovr/postgres-xl,janebeckman/gpdb,Quikling/gpdb,xinzweb/gpdb,xinzweb/gpdb,randomtask1155/gpdb,lintzc/gpdb,lisakowen/gpdb,CraigHarris/gpdb,Postgres-XL/Postgres-XL,ashwinstar/gpdb,ashwinstar/gpdb,chrishajas/gpdb,zaksoup/gpdb,atris/gpdb,yuanzhao/gpdb,tpostgres-projects/tPostgres,ahachete/gpdb,50wu/gpdb,CraigHarris/gpdb,kaknikhil/gpdb,greenplum-db/gpdb,chrishajas/gpdb,snaga/postgres-xl,kmjungersen/PostgresXL,ahachete/gpdb,oberstet/postgres-xl,lintzc/gpdb,pavanvd/postgres-xl,jmcatamney/gpdb,jmcatamney/gpdb,jmcatamney/gpdb,techdragon/Postgres-XL,Chibin/gpdb,greenplum-db/gpdb,janebeckman/gpdb,Quikling/gpdb,yuanzhao/gpdb,atris/gpdb,zaksoup/gpdb,rubikloud/gpdb,lpetrov-pivotal/gpdb,lisakowen/gpdb,rvs/gpdb,snaga/postgres-xl,lintzc/gpdb,50wu/gpdb,Postgres-XL/Postgres-XL,xinzweb/gpdb,yuanzhao/gpdb,janebeckman/gpdb,postmind-net/postgres-xl,Chibin/gpdb,lintzc/gpdb,ahachete/gpdb,zaksoup/gpdb,foyzur/gpdb,0x0FFF/gpdb,0x0FFF/gpdb,snaga/postgres-xl,kmjungersen/PostgresXL,lpetrov-pivotal/gpdb,rvs/gpdb,CraigHarris/gpdb,Chibin/gpdb,randomtask1155/gpdb,xinzweb/gpdb,xuegang/gpdb,lintzc/gpdb,janebeckman/gpdb,pavanvd/postgres-xl,ashwinstar/gpdb,atris/gpdb,cjcjameson/gpdb,cjcjameson/gpdb,tangp3/gpdb,royc1/gpdb,Postgres-XL/Postgres-XL,techdragon/Postgres-XL,tangp3/gpdb,rvs/gpdb,arcivanov/postgres-xl,cjcjameson/gpdb,lpetrov-pivotal/gpdb,arcivanov/postgres-xl,zeroae/postgres-xl,lisakowen/gpdb,yuanzhao/gpdb,Chibin/gpdb,50wu/gpdb,yazun/postgres-xl,foyzur/gpdb,randomtask1155/gpdb,lisakowen/gpdb,zaksoup/gpdb,ahachete/gpdb,cjcjameson/gpdb,janebeckman/gpdb,postmind-net/postgres-xl,lisakowen/gpdb,lpetrov-pivotal/gpdb,janebeckman/gpdb,50wu/gpdb,janebeckman/gpdb,atris/gpdb,tpostgres-projects/tPostgres,ashwinstar/gpdb,zaksoup/gpdb,xinzweb/gpdb,0x0FFF/gpdb,randomtask1155/gpdb,Postgres-XL/Postgres-XL,xuegang/gpdb,Chibin/gpdb,adam8157/gpdb,kmjungersen/PostgresXL,edespino/gpdb,randomtask1155/gpdb,kaknikhil/gpdb,atris/gpdb,cjcjameson/gpdb,jmcatamney/gpdb,Quikling/gpdb,techdragon/Postgres-XL,yuanzhao/gpdb,xuegang/gpdb,rubikloud/gpdb,edespino/gpdb,Chibin/gpdb,oberstet/postgres-xl,adam8157/gpdb,yazun/postgres-xl,oberstet/postgres-xl,postmind-net/postgres-xl,tangp3/gpdb,postmind-net/postgres-xl,CraigHarris/gpdb,Quikling/gpdb,foyzur/gpdb,xuegang/gpdb,adam8157/gpdb,ashwinstar/gpdb,chrishajas/gpdb,edespino/gpdb,lintzc/gpdb,0x0FFF/gpdb,oberstet/postgres-xl,foyzur/gpdb,postmind-net/postgres-xl,50wu/gpdb,rvs/gpdb,adam8157/gpdb,edespino/gpdb,arcivanov/postgres-xl,edespino/gpdb,zeroae/postgres-xl,kaknikhil/gpdb,rubikloud/gpdb,CraigHarris/gpdb,greenplum-db/gpdb,rubikloud/gpdb,CraigHarris/gpdb,lisakowen/gpdb,yuanzhao/gpdb,royc1/gpdb,lintzc/gpdb,pavanvd/postgres-xl,kmjungersen/PostgresXL,snaga/postgres-xl,Quikling/gpdb,yuanzhao/gpdb,royc1/gpdb,tangp3/gpdb,randomtask1155/gpdb,Quikling/gpdb,ovr/postgres-xl,kaknikhil/gpdb,foyzur/gpdb,jmcatamney/gpdb,rvs/gpdb,tpostgres-projects/tPostgres,CraigHarris/gpdb,Chibin/gpdb,cjcjameson/gpdb,yazun/postgres-xl,jmcatamney/gpdb,tangp3/gpdb,yuanzhao/gpdb,ahachete/gpdb,atris/gpdb,cjcjameson/gpdb,Quikling/gpdb,ahachete/gpdb,kaknikhil/gpdb,greenplum-db/gpdb,edespino/gpdb,xuegang/gpdb,lintzc/gpdb