PG_REORG Utility for VACUUM FULL online
pg_reorg is a utility made by NTT for reorganizing the table structure. Concept is simple, if you have all the require pointers and data in same page, then accessing those is much more faster. This is what pg_reorg provides to a user. Following are some options, which pg_reorg provides. -o [ —order-by] columns: This option makes pg_reorg to oraganise the table data as per the mentioned column. At the backend pg_reorg will creates a new table using CTAS and SELECT Query include ORDER BY clause with columns mentioned with -o. -n [—no-order] tablename: When this option is being used, then pg_reorg, does the VACUUM FULL ONLINE. Now, question is how it must be doing. Simple Concept, create a new table using CTAS and create a trigger on current table to track the DML. As the New table got created play those tracked DML on new table. It works well. This option is only for table which has primary key. pg_reorg by default does the CLUSTER of tables and it follows same concept, i.e wit