createIndexCount

Last updated: September 2, 2025

createIndexCount is a custom policy check that ensures a table has less than a specified number of indexes.

Learn how to create and customize the createIndexCount Liquibase Custom Policy Check using a Python script.

This example works for relational databases. You can use this check as it is or customize it further to fit your needs in your SQL database.

For a conceptual overview of this feature, see Liquibase Pro Custom Policy Checks.

Before you begin

Scope	Database
database	Relational

Before you begin

Liquibase 4.29.0+
Python 3.10.14+
Configure a valid Liquibase Pro license key
Create a Check Settings file
Ensure the Liquibase Checks extension is installed. In Liquibase 4.31.0+, it is already installed in the /liquibase/internal/lib directory, so no action is needed.
If the checks JAR is not installed, download liquibase-checks-<version>.jar and put it in the liquibase/lib directory.
- Maven users only:
  Add this dependency to your pom.xml
  
  file: <dependency> <groupId>org.liquibase.ext</groupId> <artifactId>liquibase-checks</artifactId> <version>2.0.0</version> </dependency>
Java Development Kit 17+ (available for Open JDK and Oracle JDK)
Linux, macOS, or Windows operating system

Procedure

These steps describe how to create the Custom Policy Check. It does not exist by default in Liquibase Pro.

Add this code to your Checks Settings file:

createIndexCount Python Script

# # #
# # # This script ensures a table has less than x indexes
# # #
# # # Notes:
    # # # 1. Uses liquibase_utilities cache to aggregate index totals across changesets
# # #

# # #
# # # Helpers come from Liquibase
# # #
import liquibase_utilities
import sys

# # #
# # # Functions
# # #
def find_snapshot_object(object_list, type, key, value):
    ""
"Returns a snapshot object given a key (e.g., name) and attribute."
""
for object in object_list:
    if object[type][key].lower() == value.lower():
    return object
return None

# # #
# # # main
# # #

# # #
# # # Retrieve log handler
# # # Ex.liquibase_logger.info(message)
# # #
liquibase_logger = liquibase_utilities.get_logger()

# # #
# # # Retrieve status handler
# # #
liquibase_status = liquibase_utilities.get_status()

# # #
# # # Retrieve JSON snapshot
# # #
liquibase_snapshot = liquibase_utilities.get_snapshot()

# # #
# # # Exit
if table data is missing
# # #
if "liquibase.structure.core.Table"
not in liquibase_snapshot["snapshot"]["objects"]:
    liquibase_status.fired = False
liquibase_logger.warning("Table data missing from snapshot. Check skipped.")
sys.exit(1)

# # #
# # # Retrieve columns and tables from snapshot
# # #
all_tables = liquibase_snapshot["snapshot"]["objects"]["liquibase.structure.core.Table"]

# # #
# # # Retrive maximum size from check definition
# # #
max_index = int(liquibase_utilities.get_arg("MAX_INDEX"))

# # #
# # # Retrieve all changes in changeset
# # #
changes = liquibase_utilities.get_changeset().getChanges()

# # #
# # # Loop through all changes
# # #
for change in changes:
    # # #
# # # LoadData change types are not currently supported
# # #
if "loaddatachange" in change.getClass().getSimpleName().lower():
    liquibase_logger.info("LoadData change type not supported. Statement skipped.")
continue
# # #
# # # Retrieve sql as string, remove extra whitespace
# # #
raw_sql = liquibase_utilities.strip_comments(liquibase_utilities.generate_sql(change)).casefold()
raw_sql = " ".join(raw_sql.split())
# # #
# # # Split raw_sql into statements
# # #
raw_statements = liquibase_utilities.split_statements(raw_sql)
for raw_statement in raw_statements:
    # # #
# # # Split raw_statement into list
# # #
sql_list = raw_statement.split()
# # #
# # # CREATE[UNIQUE] INDEX NAME ON[SCHEMA.] TABLE(column1, column2, ...)
# # #
try:
if (sql_list[0] == "create") and(sql_list[1] == "index"
        or sql_list[2] == "index"):
    start = sql_list.index("on")
# # #
# # # Remove schema and parenthesis
if provided
# # #
table_name = sql_list[start + 1].split(".")[-1]
start = table_name.rfind("(")
if start != -1:
    table_name = table_name[0: start]
else:
    raise UserWarning
except(IndexError, ValueError):
    liquibase_logger.warning(f "Unsupported Create Index statement skipped: {raw_statement}")
continue
except UserWarning:
    liquibase_logger.info(f "Non Create Index statement skipped: {raw_statement}")
continue
# # #
# # # Locate table
# # #
table_object = find_snapshot_object(all_tables, "table", "name", table_name.strip())
if table_object is None:
    liquibase_logger.warning(f "Table \"{table_name}\" not found in snapshot. Statement skipped.")
continue
table_name = table_object['table']['name']
# # #
# # # Sum indexes, check
for maximum
# # #
index_total = liquibase_utilities.get_cache(table_name, 1)
if "indexes" in table_object["table"]:
    index_total += len(table_object["table"]["indexes"])
liquibase_utilities.put_cache(table_name, index_total)
if index_total > max_index:
    liquibase_status.fired = True
status_message = str(liquibase_utilities.get_script_message()).replace("__TABLE_NAME__", f "\"{table_name}\"")
status_message = status_message.replace("__INDEX_COUNT__", str(index_total))
liquibase_status.message = status_message
sys.exit(1)

# # #
# # # Default
return code
# # #
False

Initiate the customization process

In the CLI, run this command:

liquibase checks customize --check-name=CustomCheckTemplate

The CLI prompts you to finish configuring your file. A message displays:

This check cannot be customized directly because one or more fields does not have a default value.

Liquibase will then create a copy of CustomCheckTemplate and initiate the customization workflow.

Give your check a short name so you can easily identify what Python script it is associated with

Use up to 64 alpha-numeric characters only. In this example we will name the check:

createIndexCount

Set the Severity to return a code of 0-4 when triggered.

These severity codes allow you to determine if the job moves forward or stops when this check triggers. Learn more here: Use Policy Checks in Automation: Severity and Exit Code options: 'INFO'=0, 'MINOR'=1, 'MAJOR'=2, 'CRITICAL'=3, 'BLOCKER'=4

Set the SCRIPT_DESCRIPTION

In this example, we will set the description to:

This script ensures a table has less than a specified number of indexes.

Set the SCRIPT_SCOPE

In this example, we will set the scope to:

database: If your check looks for the presence of keys, indexes, or table name patterns in your database schema including Liquibase Tracking Tables. With this value, the check runs once for each database object.

Set the SCRIPT_MESSAGE

This message will display when the check is triggered. In this example we will use:

This script identified that Table __TABLE_NAME__ has __INDEX_COUNT__ indexes.

Set the SCRIPT_PATH

This is the relative path where your script is stored in relation to the changelog specified in --changelog-file, whether it is stored locally or in a repository. In this example, we will set the path to:

scripts/create-index-count.py.

Set the SCRIPT_ARGUMENT.

This allows you to pass dynamic information into the custom policy check without modifying the Python code. Specify MAX_SIZE=2 in the CLI to retrieve it in your code with the variable: max_size = int (liquibase_utilities.get_arg("MAX_SIZE")). If you customize your check later, you can specify a new value in the CLI. If you don't need dynamic arguments, leave this field blank.

Set the REQUIRES_SNAPSHOT

If your script scope is changelog, set whether the check requires a database snapshot. Specify true if your check needs to inspect database objects.

If your script scope is database, Liquibase always takes a snapshot, so this prompt does not appear.

Note: The larger your database, the more performance impact a snapshot causes. If you cannot run a snapshot due to memory limitations, see Memory Limits of Inspecting Large Schemas.