Revise _bt_binsrch() so that its binary search loop takes care of equal-key cases, eliminating bt_firsteq().  The linear search formerly done by bt_firsteq() took a lot of time in the case where many equal keys appear on the same page.
Revise _bt_binsrch() so that its binary search loop takes
care of equal-key cases, eliminating bt_firsteq().  The linear search
formerly done by bt_firsteq() took a lot of time in the case where many
equal keys appear on the same page.

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