Postgres: postgres way to rebuild index online.

create index concurrently NEW_INDEX on TABLE_NAME (COLUMN NAME)
BEGIN;
DROP INDEX OLD_IND;
ALTER INDEX NEW_INDEX RENAME TO OLD_INDEX;
COMMIT;

Experiment

gnb=# \d pgbench_accounts;

      Table "public.pgbench_accounts"

    Column     |     Type      | Modifiers

---------------+---------------+-----------

 aid           | integer       | not null

 bid           | integer       |

 abalance      | integer       |

 filler        | character(84) |

 modified_date | date          |

Indexes:

    "pgbench_accounts_pkey" PRIMARY KEY, btree (aid)

gnb=# create index accounts_ind on pgbench_accounts (abalance);

CREATE INDEX

gnb=# \d pgbench_accounts;

      Table "public.pgbench_accounts"

    Column     |     Type      | Modifiers

---------------+---------------+-----------

 aid           | integer       | not null

 bid           | integer       |

 abalance      | integer       |

 filler        | character(84) |

 modified_date | date          |

Indexes:

    "pgbench_accounts_pkey" PRIMARY KEY, btree (aid)

    "accounts_ind" btree (abalance)

gnb=#  select * from pg_indexes where tablename='pgbench_accounts';

 schemaname |    tablename     |       indexname       | tablespace |                                    indexdef

------------+------------------+-----------------------+------------+---------------------------------------------------------------------------------

 public     | pgbench_accounts | pgbench_accounts_pkey |            | CREATE UNIQUE INDEX pgbench_accounts_pkey ON pgbench_accounts USING btree (aid)

 public     | pgbench_accounts | accounts_ind          |            | CREATE INDEX accounts_ind ON pgbench_accounts USING btree (abalance)

(2 rows)

create index concurrently accounts_ind_new on pgbench_accounts (abalance);

Begin;

drop index accounts_ind;

alter index accounts_ind_new rename to old_index;

commit;

The "concurrent....ly" keyword is to prevent the table to be locked up during the creation of the index. If there is this awesome feature, why not Postgresql just make it a default behavior ???