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133 lines
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ReStructuredText
133 lines
6.0 KiB
ReStructuredText
.. _index_dialog:
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*********************
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`Index Dialog`:index:
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*********************
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Use the *Index* dialog to create an index on a specified table or materialized
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view.
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The *Index* dialog organizes the development of a index through the following
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dialog tabs: *General*, *Definition*, and *Columns*. The *SQL* tab displays the SQL code
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generated by dialog selections.
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.. image:: images/index_general.png
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:alt: Index dialog general tab
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:align: center
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Use the fields in the *General* tab to identify the index:
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* Use the *Name* field to add a descriptive name for the index. The name will
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be displayed in the *pgAdmin* tree control.
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* Use the drop-down listbox next to *Tablespace* to select the tablespace in
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which the index will reside.
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* Store notes about the index in the *Comment* field.
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Click the *Definition* tab to continue.
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.. image:: images/index_definition.png
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:alt: Index dialog definition tab
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:align: center
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Use the fields in the *Definition* tab to define the index:
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* Use the drop-down listbox next to *Access Method* to select an index type:
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* Select *btree* to create a B-tree index. A B-tree index may improve
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performance when managing equality and range queries on data that can be
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sorted into some ordering (the default).
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* Select *hash* to create a hash index. A hash index may improve
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performance when managing simple equality comparisons.
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* Select *gist* to create a GiST index. A GiST index may improve
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performance when managing two-dimensional geometric data types and
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nearest-neighbor searches.
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* Select *gin* to create a GIN index. A GIN index may improve
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performance when managing values with more than one key.
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* Select *spgist* to create a space-partitioned GiST index. A SP-GiST index
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may improve performance when managing non-balanced data structures.
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* Select *brin* to create a BRIN index. A BRIN index may improve
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performance when managing minimum and maximum values and ranges.
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* Use the *Fill Factor* field to specify a fill factor for the index. The fill
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factor specifies how full the selected method will try to fill each index
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page.
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* Use the *Gin pending list limit* field to specify the maximum size of a GIN index's pending list, which is used
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when fastupdate is enabled. This value is specified in kilobytes.
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* Use the *Pages per range* field to specify the number of table blocks that make up one block range
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for each entry of a BRIN index.
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* Select *Buffering* to specify whether the buffering build technique is used to build the index. The default is
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*Auto*
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* Move the switch next to *Deduplicate items?* towards the *right position* to control usage of the B-tree
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deduplication technique. The default is *Yes*. This option is available only on PostgreSQL 13 and above.
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* Move the switch next to *Fast update?* towards the *right position* to control usage of the fast update technique.
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The default is *Yes*.
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* Move the switch next to *Autosummarize* towards the *right position* to define whether a summarization run is
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queued for the previous page range whenever an insertion is detected on the next one. The default is *No*
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* Move the switch next to *Unique?* towards the *right position* to check for duplicate values
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in the table when the index is created and when data is added. The default is *No*.
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* Move the switch next to *NULLs not distinct?* towards the *right position* to treat null values as not distinct.
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The default is*No*. This option is available only on PostgreSQL 15 and above.
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* Move the *Clustered?* switch to the *Yes* position to instruct the server to
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cluster the table.
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* Move the *Concurrent build?* switch to the *Yes* position to build the index
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without taking any locks that prevent concurrent inserts, updates, or deletes
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on the table.
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* Use the *Constraint* field to provide a constraint expression; a constraint
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expression limits the entries in the index to those rows that satisfy the
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constraint.
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Click the *Columns* tab to continue.
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.. image:: images/index_columns.png
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:alt: Index dialog columns tab
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:align: center
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Use the fields in the *Columns* tab to specify which column(s) or expression(s)
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the index queries. Use the *Is expression ?* switch to enable
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expression sql input. Use the drop-down listbox next to *Column*
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to select a column. Once the *Column* is selected or the *Expression* is
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entered then click the *Add* icon (+) to provide details of the action on the
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column/expression:
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* The *Col/Exp* field is populated with the selection made in the *Column*
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drop-down listbox or the *Expression* entered.
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* If enabled, use the drop-down listbox to select an available *Operator class*
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to specify the type of action performed on the column.
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* If enabled, use the drop-down listbox to select *Sort order*:
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* Select *ASC* to specify an ascending sort order (the default);
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* Select *DESC* to specify a descending sort order.
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* If enabled, use the drop-down listbox to select *Nulls*:
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* Select *First* to specify nulls sort before non-nulls;
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* Select *Last* to specify nulls sort after non-nulls (the default).
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* Use the drop-down listbox in the *Collation* field to select a collation to
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use for the index.
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Use *Include columns* field to specify columns for *INCLUDE* clause of the
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constraint. This option is available in Postgres 11 and later.
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Click the *SQL* tab to continue.
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Your entries in the *Index* dialog generate a SQL command (see an example
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below). Use the *SQL* tab for review; revisit or switch tabs to make any
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changes to the SQL command.
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Example
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*******
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The following is an example of the sql command generated by user selections in
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the *Index* dialog:
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.. image:: images/index_sql.png
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:alt: Index dialog sql tab
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:align: center
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The example shown demonstrates creating an index named *index_sal* that indexes
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the values in the *job* column of the *jobhist* table.
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* Click the *Info* button (i) to access online help.
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* Click the *Save* button to save work.
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* Click the *Close* button to exit without saving work.
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* Click the *Reset* button to restore configuration parameters.
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