From: "Lun Wing San (Oracle)" Subject: Re: exp: why have statistics=estimate option? Date: 1997/01/01 Message-ID: <32CAA611.1C0A@qrcsun.qrc.org>#1/1 references: <32c80c9b.17843869@n5.gbso.net> to: Chuck Hamilton content-type: text/plain; charset=us-ascii organization: Lun's Oracle Solution Company mime-version: 1.0 newsgroups: comp.databases.oracle.misc x-mailer: Mozilla 2.02 (Win16; I) Chuck Hamilton wrote: > > Maybe this is a dumb question, but why even have the > 'statistics=estimate' option in the export utility? When a table gets > imported, the _exact_ number of rows imported is already available. > Why not just use that number to populate DBA_TABLES.NUM_ROWS instead > of going through the time consuming process of issuing an ANALYZE > TABLE command? ANALYZE can help you to populate the statistics information into DBA_TABLES, DBA_INDEXES, DBA_TAB_COLUMNS, INDEX_STAT, INDEX_HISTOGRAMS. By using these statistics, you can carry out cost-based optimization in the execution of a DML if OPTIMIZER_GOAL is set to CHOOSE, ALL_ROWS or FIRST_ROWS. --- Name : Lun Wing San Title : Oracle Application Developer of Hong Kong Productivity Council Oracle Database Administrator and System Administrator of QRC Phone : (852)27885841