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sys.sp_verify_database_ledger (Transact-SQL)

  • Straipsnis

Applies to: SQL Server 2022 (16.x) Azure SQL Database Azure SQL Managed Instance

Verifies the database ledger and the table ledgers. For each row in the sys.database_ledger view, the stored procedure:

  1. Recomputes a value stored in the previous_block_hash column of the row.
  2. Checks if the recomputed value matches the value currently stored in the previous_block_hash column.
  3. If the specified list of digests contains a digest for the ledger block the row represents, it verifies the recomputed value matches the hash in the digest.
  4. If a ledger table name is specified using the table_name argument, the stored procedure verifies a table hash for the specified table, if it exists in the table_hashes column of sys.database_ledger. Otherwise, it verifies all table hashes existing in the table_hashes column of sys.database_ledger, except table hashes for non-existing (dropped) tables. When verifying a table hash for a ledger table, the stored procedure:
    1. Scans the history table of the ledger table to recompute the table hash, which is a hash of all rows updated by the transaction represented by the current row in sys.database_ledger in the ledger table.
    2. Checks if the recomputed table hash matches the value stored in the table_hashes column of sys.database_ledger for the given ledger table.

In addition, the stored procedure verifies all nonclustered indexes are consistent with the specified ledger table. If no ledger table is specified, it verifies all nonclustered indexes for each existing ledger table referenced in the table_hashes column in any row of sys.database_ledger.

For more information on database ledger, see Ledger.

Transact-SQL syntax conventions

Syntax

sp_verify_database_ledger
    [ @digests = ] 'digests'
    [ , [ @table_name = ] 'table_name' ]

Arguments

[ @digests = ] 'digests'

A JSON document containing a list of transaction digests, each of which has been obtained by querying the sys.database_ledger_latest_digest view. The JSON document must contain at least one digest.

[ @table_name = ] 'table_name'

The name of the table that you want to verify.

Return code values

0 (success) or 1 (failure).

Result set

One row, with one column called last_verified_block_id.

Permissions

Requires the VIEW LEDGER CONTENT permission.

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