deduplicate_items

Description

Controls usage of the B-tree deduplication technique described in Section 65.1.4.3 . Set to ON or OFF to enable or disable the optimization. (Alternative spellings of ON and OFF are allowed as described in Section 19.1 .) The default is ON .

Turning deduplicate_items off via ALTER INDEX prevents future insertions from triggering deduplication, but does not in itself make existing posting list tuples use the standard tuple representation.

Applies to

B-tree indexes

Value type

boolean

Default

ON

Usage

WITH (deduplicate_items = value)

Index access method

This entry applies to B-tree indexes. Set it with CREATE INDEX WITH or ALTER INDEX SET. Read defaults and behavior for this specific access method.

Related entries

• CREATE INDEX

Documentation and source

• PostgreSQL 18 English manual

Compare versions

PostgreSQL 12 → 13: added.

--- PostgreSQL 12
+++ PostgreSQL 13
@@ -1 +1,18 @@
-Not recorded in this version
+{
+  "facts": [
+    {
+      "label": "Applies to",
+      "value": "B-tree indexes"
+    },
+    {
+      "label": "Value type",
+      "value": "boolean"
+    },
+    {
+      "label": "Default",
+      "value": "ON"
+    }
+  ],
+  "signature": "WITH (deduplicate_items = value)",
+  "tables": null
+}

Compares recorded interfaces and attributes. Source fingerprints and build metadata are excluded; an absent sample is not proof of the introduction or removal release.

Related entries

• fillfactorB-tree indexes fillfactor