压缩或缩小表的空间时,先要

alter table v4 enable row movement;

alter table v4 shrink space compact;

shrink 语句的相当注意限制:

Restrictions on the shrink_clause The shrink_clause is subject to the following restrictions:

You cannot specify this clause for a cluster, a clustered table, or any object with a LONG column.
Segment shrink is not supported for tables with function-based indexes or bitmap join indexes.
This clause does not shrink mapping tables of index-organized tables, even if you specify CASCADE.
You cannot specify this clause for a compressed table.
You cannot shrink a table that is the master table of an ON COMMIT materialized view. Rowid materialized views must be rebuilt after the shrink operation.

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oracle 10g__alter table shrink space compact