Change cross datacenter metadata, add db to it.
Merge remote-tracking branch 'origin/zjw' into macan, view desc.
Merge remote-tracking branch 'origin/zjw' into macan, add missing files.
add online_sfilelocation for realtime search.
Merge remote-tracking branch 'origin/zjw' into macan, ddl fix.
DDL add show files/filelocations/nodes'