Exceptions

RedisVL defines its custom exceptions in redisvl.exceptions. Every one of them inherits from RedisVLError, so catching that single base class is enough to handle any error the core index and query APIs raise on their own behalf. Catch the more specific subclasses when you want to react differently to, for example, a schema validation failure than to a Redis connection problem. (The MCP integration defines its own redisvl.mcp.errors.RedisVLMCPError, which is outside this hierarchy.)

Exception
└── RedisVLError
    ├── RedisSearchError
    ├── SchemaValidationError
    ├── QueryValidationError
    └── RedisModuleVersionError

When each error is raised

All of the above apply equally to SearchIndex and AsyncSearchIndex.

Handling errors

Validating data on load

Schema validation is off by default. Pass validate_on_load=True to have RedisVL check each object against the index schema before writing it, and raise SchemaValidationError on the first object that does not match.

from redisvl.index import SearchIndex
from redisvl.exceptions import SchemaValidationError

index = SearchIndex.from_yaml(
    "schema.yaml",
    redis_url="redis://localhost:6379",
    validate_on_load=True,
)

try:
    index.load(data)
except SchemaValidationError as e:
    # The message identifies the offending object by its position in the
    # input and describes which field failed and why.
    print(f"Invalid record: {e}")

The error message reports the index of the object within the batch you passed, so a failure part way through a large load still points at a specific record.

Handling query failures

QueryValidationError signals a query that cannot run against this index. It is a programming error rather than a transient one, so it is usually worth failing loudly instead of retrying.

from redisvl.query import VectorQuery
from redisvl.exceptions import QueryValidationError

query = VectorQuery(
    vector=[0.1, 0.2, 0.3],
    vector_field_name="embedding",
    return_fields=["title"],
    ef_runtime=50,  # only supported by the 'hnsw' algorithm
)

try:
    results = index.query(query)
except QueryValidationError as e:
    print(f"Query rejected: {e}")

Separating configuration problems from Redis problems

RedisModuleVersionError is a subclass of RedisVLError, not of RedisSearchError, so ordering the except clauses lets you distinguish an unsupported feature from a genuine Redis failure.

from redisvl.exceptions import RedisModuleVersionError, RedisSearchError

try:
    index.create(overwrite=True)
except RedisModuleVersionError as e:
    # The deployment does not support the requested feature, for example an
    # 'svs-vamana' field on a Redis version without a new enough Redis Search.
    print(f"Unsupported by this Redis deployment: {e}")
except RedisSearchError as e:
    # Something went wrong talking to Redis, or the index definition was
    # rejected. The original redis-py exception is available as e.__cause__.
    print(f"Index creation failed: {e}")

Insufficient permissions usually arrive as RedisSearchError as well. create() checks whether the index already exists before doing anything, so a credential that cannot run FT.INFO fails at that check rather than at FT.CREATE, with the chained redis.exceptions.NoPermissionError on e.__cause__ naming the denied command. The same applies to an existing index whose key prefix falls outside the credential’s key patterns; for an index that does not exist yet, the check simply reports it as absent and create() proceeds.

listall() is the exception: it issues FT._LIST directly, so a permission failure there raises redis.exceptions.NoPermissionError itself rather than a wrapped RedisSearchError. See Install RedisVL for the ACL categories RedisVL needs.

Telling "the index is missing" apart from other failures

Redis Search reports an absent index as an ordinary error reply rather than a distinct type, and the wording has changed between versions – older releases say Unknown index name, Redis 8.6 and earlier say <name>: no such index, and Redis 8.8 introduced SEARCH_INDEX_NOT_FOUND Index not found: <name>. There is no error code to branch on, so code that needs to distinguish "missing" from "something went wrong" has to match the message.

exists() already does this for you, which is the reason to prefer it over catching errors from info(): it returns False only for a recognized missing-index reply and re-raises everything else, so a permission or connection failure is never reported as an absent index.

# Prefer this
if not index.exists():
    index.create()

# over inspecting the error yourself, which couples your code to the
# wording of a particular Redis version
try:
    index.info()
except RedisSearchError as e:
    if "no such index" in str(e):  # breaks on Redis 8.8
        index.create()

When you do need the distinction elsewhere, read e.__cause__ rather than the RedisSearchError message: the wrapper interpolates the index name, so an index whose name happens to contain one of the wordings above would make an unrelated failure look like an absence.

Catching everything

When the calling code only needs to know that the operation failed, catch the base class.

from redisvl.exceptions import RedisVLError

try:
    index.load(data)
    results = index.query(query)
except RedisVLError as e:
    logger.error("RedisVL operation failed: %s", e)
    raise

Because RedisVL chains the underlying exception when it wraps one, e.__cause__ still holds the original redis-py error where there was one.

Exception classes

RedisVLError

class RedisVLError

Bases: Exception

Base exception for all RedisVL errors.

RedisSearchError

class RedisSearchError

Bases: RedisVLError

Error raised for Redis Search specific operations.

SchemaValidationError

class SchemaValidationError(message, index=None)

Bases: RedisVLError

Error when validating data against a schema.

QueryValidationError

class QueryValidationError

Bases: RedisVLError

Error when validating a query.

RedisModuleVersionError

class RedisModuleVersionError

Bases: RedisVLError

Error when Redis or module versions are incompatible with requested features.

classmethod for_svs_vamana(min_redis_version)

Create error for unsupported SVS-VAMANA.

• Parameters: min_redis_version (str) – Minimum required Redis version
• Returns: RedisModuleVersionError with formatted message