Chapter 37: The Hitchhiker’s Guide to the Oracle9i Data Dictionary 717 The analyze command can be used to generate a listing of the chained rows within a table. This listing of chained rows can be stored in a table called CHAINED_ROWS. To create the CHAINED_ROWS table in your schema, run the script (usually found in the /rdbms/ admin subdirectory under the Oracle home directory). To populate the CHAINED_ROWS table, use the list chained rows into clause of the analyze command, as shown in the following listing: analyze TABLE BIRTHDAY list chained rows into CHAINED_ROWS; The CHAINED_ROWS table lists the Owner_Name, Table_Name, Cluster_Name (if the. | Chapter 37 The Hitchhiker s Guide to the Oracle9i Data Dictionary 717 The analyze command can be used to generate a listing of the chained rows within a table. This listing of chained rows can be stored in a table called CHAINED_ROWS. To create the CHAINED_ROWS table in your schema run the script usually found in the rdbms admin subdirectory under the Oracle home directory . To populate the CHAINED_ROWS table use the list chained rows into clause of the analyze command as shown in the following listing t analyze TABLE BIRTHDAY list chained rows into CHAINED_ROWS The CHAINED_ROWS table lists the Owner_Name Table_Name Cluster_Name if the table is in a cluster Partition_Name if the table is partitioned Subpartition_Name if the table contains subpartitions Head_RowID the RowID for the row and an Analyze_TimeStamp column that shows the last time the table or cluster was analyzed. You can query the table based on the Head_RowID values in CHAINED_ROWS as shown in the following example I select from BIRTHDAY where RowID in select Head_RowID from CHAINED_ROWS where Table_Name BIRTHDAY If the chained row is short in length then it may be possible to eliminate the chaining by deleting and reinserting the row. PLAN_TABLE When tuning SQL statements you may want to determine the steps that the optimizer will take to execute your query. To view the query path you must first create a table in your schema named PLAN_TABLE. The script used to create this table is called and is usually stored in the rdbms admin subdirectory of the Oracle software home directory. After you have created the PLAN_TABLE table in your schema you can use the explain plan command which will generate records in your PLAN_TABLE tagged with the Statement_ID value you specify for the query you want to have explained t explain plan set Statement_ID MYTEST for select from BIRTHDAY where LastName like S The ID and Parent_ID columns in PLAN_TABLE establish the hierarchy of steps Operations