Create Index

In this section, you will find information about the transformation done to the Create Index in Oracle.

Currently, Create Index statement is not being converted but it is being parsed. Also, if your source code has create index statements, these are going to be accounted for in the Assessment Report.

Example of a create index parsed code:

CREATE UNIQUE INDEX COL1_INDEX ILM (ADD POLICY OPTIMIZE AFTER 10 DAYS OF NO ACCESS) ON CLUSTER CLUSTER1
ONLINE USABLE DEFERRED INVALIDATION;

CREATE BITMAP INDEX COL1_INDEX ILM (ADD POLICY OPTIMIZE ( ON FUNC1 )) ON TABLE1 AS TAB1 (COL1 ASC) GLOBAL PARTITION BY RANGE (COL1, COL2) ( PARTITION VALUES LESS THAN (MAXVALUE) ) UNUSABLE IMMEDIATE INVALIDATION;

CREATE MULTIVALUE INDEX COL1_INDEX ILM (ADD POLICY SEGMENT TIER TO LOW_COST_TBS) ON TABLE1( TAB1 COL1 DESC, TAB1 COL2 ASC) FROM TABLE1 AS TAB1 WHERE COL1 > 0 LOCAL STORE IN (STORAGE1)
VISIBLE USABLE DEFERRED INVALIDATION;

CREATE INDEX COL1_INDEX ILM (DELETE POLICY POLICY1) ON CLUSTER CLUSTER1
PCTFREE 10
LOGGING
ONLINE
TABLESPACE DEFAULT
NOCOMPRESS
SORT
REVERSE
VISIBLE
INDEXING PARTIAL
NOPARALLEL;

CREATE INDEX COL1_INDEX ILM (DELETE_ALL) ON TABLE1 AS TAB1 (COL1 ASC) LOCAL (
PARTITION PARTITION1 TABLESPACE TABLESPACE1 NOCOMPRESS USABLE) DEFERRED INVALIDATION;

CREATE INDEX COL1_INDEX ON TABLE1 (COL1 ASC) GLOBAL
PARTITION BY HASH (COL1, COL2) (PARTITION PARTITION1 LOB(LOB1) STORE AS BASICFILE LOB_NAME (TABLESPACE TABLESPACE1)) USABLE IMMEDIATE INVALIDATION;

CREATE INDEX COL1_INDEX ON TABLE1 (COL1 DESC, COL2 ASC) INDEXTYPE IS INDEXTYPE1 LOCAL ( PARTITION PARTITION1 PARAMETERS('PARAMS')) NOPARALLEL PARAMETERS('PARAMS') USABLE DEFERRED INVALIDATION;

CREATE INDEX COL1_INDEX ON TABLE1 (COL1 ASC) INDEXTYPE IS XDB.XMLINDEX LOCAL ( PARTITION PARTITION1) PARALLEL 6 UNUSABLE IMMEDIATE INVALIDATION;

Due to architectural reasons, Snowflake does not support indexes so, SnowConvert will remove all the code related to the creation of indexes. Snowflake automatically creates micro-partitions for every table that help speed up the performance of DML operations, the user does not have to worry about creating or managing these micro-partitions.

Usually, this is enough to have an exceptionally good query performance. However, there are ways to improve it by creating data clustering keys. Snowflake's official page provides more information about micro-partitions and data clustering.