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Difference between revisions of "IBM CMOD Composite Indexes"
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IBM CMOD Composite Indexes (view source)
Revision as of 16:09, 22 August 2018
, 16:09, 22 August 2018Added IBM CMOD Performance image, corrected spelling mistakes.
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In IBM Content Manager OnDemand, an Application Group's field type can be set to Filter or Index. Setting the type to 'Index' tells CMOD that it should instruct the database to build an index for that field. Setting the value to Filter means that the field is used to filter the results after the index search is completed. | In IBM Content Manager OnDemand, an Application Group's field type can be set to Filter or Index. Setting the type to 'Index' tells CMOD that it should instruct the database to build an index for that field. Setting the value to Filter means that the field is used to filter the results after the index search is completed. | ||
Database indexes make access to data faster by storing a value with the location of the data in the index -- similar to how the index | Database indexes make access to data faster by storing a value with the location of the data in the index -- similar to how the index at the back of a reference book works. The advantage is that if the data being indexed is mostly unique ("high cardinality") the indexes can be used to make searches very fast. In OnDemand, fields that are set to 'Index' should also have the 'Required' checkbox selected in the Folder configuration, Field Information Tab. | ||
For those who like analogies: Using 'Filter' Field Type is like trying to find a word by searching every page in a very long book. Using 'Index' is like using the Index at the back of a book, telling you where to find each | For those who like analogies: Using 'Filter' Field Type is like trying to find a word by searching every page in a very long book. Using 'Index' is like using the Index at the back of a book, telling you where to find each occurrence of the word by page number. In fact, this naming convention is used in databases -- index point to database pages, which contain records ("words"). | ||
Composite Indexes are database indexes that are created by adding the values of two or more fields together. If the fields selected for the composite indexes are mostly unique (high specificity or cardinality) the index may be very large, but it should be able to identify a single record -- and be extraordinarily efficient in the process. In order to be effective at reducing the duration of queries, ALL of the fields that appear in the composite index must also be set to be 'Required' fields in the Folder configuration. | Composite Indexes are database indexes that are created by adding the values of two or more fields together. If the fields selected for the composite indexes are mostly unique (high specificity or cardinality) the index may be very large, but it should be able to identify a single record -- and be extraordinarily efficient in the process. In order to be effective at reducing the duration of queries, ALL of the fields that appear in the composite index must also be set to be 'Required' fields in the Folder configuration. | ||
[[File:RequiringIndexedFields.png|Improving IBM CMOD Performance by Requiring Indexed Fields ]] | |||
= Usage = | = Usage = | ||