Add WAL mmap() mention.
Add WAL mmap() mention.

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