Add example for converting epoch back to timestamp.
Add example for converting epoch back to timestamp.

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