Add:
Add:

> * Auto-vacuum
> 	o Move into the backend code
> 	o Scan the buffer cache to find free space or use background writer
> 	o Use free-space map information to guide refilling

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