> ## Documentation Index
> Fetch the complete documentation index at: https://docs.regatta.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Modifying a Vector Index

The following command alters a vector index.

## Synopsis

```sql theme={null}
ALTER VECTOR INDEX index_name 
  action [, ...] 

where action is one of the following: 
  ADD MODULE module_idname [ parallelism ] 
  DROP MODULE module_idname 
  ABORT MODULE ALL 
```

## Description

This command can be used to add modules to and remove modules from an existing vector index. It can also be used to abort the build process for modules on which the index is currently being built. 

Each `ALTER VECTOR INDEX` command may include only one type of clause out of `ADD`, `DROP `and `ABORT`. It can include multiple clauses of the same type. 

Adding modules initiates the build process for the rows residing in the specified modules. The command returns once the build process has been initiated. Only after the build process is completed, the rows residing on those modules are included in approximate vector search. The `SHOW VECTOR INDEX MODULES` command (see [Show Vector Index Modules](/sql/vector-index/show-commands#show-vector-index-modules)) can be used to query the status of the build process on the modules. 

Dropped modules must be in final state, i.e. `COMPLETE `or `FAILED`. (See [Show Vector Index Modules](/sql/vector-index/show-commands#show-vector-index-modules) command for description of module states). Aborted modules must be in state `BUILDING`, i.e., during the build process. 

Dropping all the modules of a vector index does not cause dropping of the index. The index remains with zero modules, and it’s a valid state. However, trying to perform approximate search queries on the index will result in an error. 

The `ABORT `clause aborts index build processes that are in progress. The aborted modules are removed from the index. 

The following limitations apply:

* The `ABORT `clause cannot specify specific modules – it must specify `ALL`and all the modules that have a build process in progress will be aborted. The pertinent modules are removed from the index. 
* While there is a build process in progress in any of the modules, adding and dropping modules is not allowed. 

Examples:

```plsql theme={null}
-- Add two modules
ALTER VECTOR INDEX my_table_vec1_hnsw_ip
	ADD MODULE module_c
	ADD MODULE module_d MEDIUM;

-- Remove one module
ALTER VECTOR INDEX my_table_vec1_hnsw_ip DROP MODULE module_b;

-- Abort any module im which the build process is in the progress
ALTER VECTOR INDEX my_table_vec1_hnsw_ip ABORT MODULE ALL;
```