> ## Documentation Index
> Fetch the complete documentation index at: https://www.cockroachlabs.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Technical Advisory 96924
export const InternalLink = ({version, path = "", children, ...props}) => {
let detectedVersion = version || "stable";
if (typeof window !== 'undefined' && !version) {
const match = window.location.pathname.match(/\/docs\/([^/]+)/);
if (match) {
detectedVersion = match[1];
}
}
const normalizedPath = path.startsWith("/") ? path.slice(1) : path;
return
{children}
;
};
Publication date: March 6, 2023
## Description
While executing `ALTER TABLE DROP COLUMN` on a column used in a partial index, all DML statements referencing the table fail with an error during the delete-only phase of the `ALTER`, which can last several hours for large tables. This includes `SELECT`, `INSERT`, `UPSERT`, `UPDATE`, and `DELETE` statements.
This problem exists in all versions of CockroachDB since the introduction of [partial indexes](https://www.cockroachlabs.com/docs/v22.2/partial-indexes) in v20.2.0.
## Statement
This is resolved in CockroachDB by a fix that disallows dropping columns that are referenced by a partial index.
This fix has been applied to maintenance releases of CockroachDB v22.1.16 and v22.2.6).
## Mitigation
Users can avoid the issue by [dropping any partial indexes](https://www.cockroachlabs.com/docs/v22.2/drop-index) using the column before [dropping the column](https://www.cockroachlabs.com/docs/v22.2/alter-table#drop-column).
Users of CockroachDB v21.2.0 through v22.1.15 and v22.2.0 through v22.2.5 are encouraged to upgrade to v22.1.16, v22.2.6, or a later version.
## Impact
When executing [`ALTER TABLE DROP COLUMN`](https://www.cockroachlabs.com/docs/v22.2/alter-table#drop-column) of a column used in a partial index, all DML statements referencing the table fail with an error during the delete-only phase. DML statements not referencing the table are not affected.
Questions about any technical alert can be directed to our [support team](https://support.cockroachlabs.com/).