Add:
Add:

>
> * Reduce XID consumption of read-only queries
>
>    http://archives.postgresql.org/pgsql-hackers/2007-08/msg00516.php
>

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