Bulk delete keys

Prerequisites

Write the keys to delete to a text file, one key per line.

Command

# UNLINK is non-blocking (Redis 4.0+). For earlier versions, use DEL.
cat <file> | xargs redis-cli -h <host> -p <port> -a <password> UNLINK

Parameters

Example

cat key.txt | xargs redis-cli -h r-bp127cu5tb*****.redis.rds.aliyuncs.com -a Test**** UNLINK

Verify the deletion

# Verify that keys are deleted. Expected result: 0
redis-cli -h <host> -p <port> -a <password> --scan --pattern '<key pattern in the file>' | wc -l

Code

import redis
import sys

def main(argv):
    if len(argv) < 4:
        print("Usage: python scan_and_del.py host port password match")
        sys.exit(-1)

    host = argv[1]
    port = argv[2]
    password = argv[3]
    match = argv[4]
    print("host: %s, port: %s, password: %s, match: %s\n" % (host, port, password, match))

    redis_cli = redis.StrictRedis(host=host, port=port, password=password)
    cursor = 0
    rnd = 1

    while rnd == 1 or cursor != 0:
        result = redis_cli.scan(cursor=cursor, match=match, count=1000)
        ret_cursor = result[0]
        ret_keys = result[1]
        num_keys = len(ret_keys)
        print("del %d keys in round %d, cursor: %d" % (num_keys, rnd, ret_cursor))
        if 0 != num_keys:
            ret_unlink = redis_cli.unlink(*ret_keys)
            print("ret_unlink: %d, ret_keys: %s" % (ret_unlink, ret_keys))
        cursor = ret_cursor
        rnd += 1
        print("")

if __name__ == '__main__':
    main(sys.argv)

Run

python scan_and_unlink.py <host> <port> <password> "<key>" 

Parameters

Pattern syntax

Verify the deletion

Verify that all matching keys are deleted:

redis-cli -h <host> -p <port> -a <password> --scan --pattern '<key>' | wc -l
# Expected output: 0

Code

import redis
import sys


def main(argv):
    if len(argv) < 4:
        print("Usage: python scan_and_del_pipeline.py host port password match")
        sys.exit(-1)

    host = argv[1]
    port = int(argv[2])  # Convert port to integer
    password = argv[3]
    match = argv[4]
    print(f"host: {host}, port: {port}, password: {'*' * len(password)}, match: {match}\n")

    # After accumulating 1000 keys, submit a DEL command through the pipeline. You can adjust this number as needed.
    pipeline_batch_size = 1000
    
    redis_cli = redis.StrictRedis(host=host, port=port, password=password, decode_responses=True)
    
    cursor = 0
    total_deleted_count = 0
    keys_to_delete = []

    print("Starting key scan...")
    # Use a 'while True' loop and exit when the cursor is 0.
    while True:
        # 1. Scan a batch of keys.
        cursor, keys = redis_cli.scan(cursor=cursor, match=match, count=1000)

        if keys:
            # 2. Collect the scanned keys into a list for deletion.
            keys_to_delete.extend(keys)

        # 3. When the deletion list reaches the batch size or the scan is complete, execute the deletion.
        if len(keys_to_delete) >= pipeline_batch_size or cursor == 0:
            if keys_to_delete:
                print(f"Accumulated {len(keys_to_delete)} keys. Preparing to delete via Pipeline...")

                # --- Pipeline -----------
                pipe = redis_cli.pipeline(transaction=False, shard_hint=None)
                pipe.delete(*keys_to_delete)
                result = pipe.execute()
                # -------------------------

                deleted_in_batch = result[0]
                total_deleted_count += deleted_in_batch

                print(f"  -> Pipeline executed. Deleted {deleted_in_batch} keys in this batch.")

                # Clear the deletion list to prepare for the next batch.
                keys_to_delete = []

        # 4. If the scan is complete, exit the loop.
        if cursor == 0:
            break

    print(f"\nScan finished. Total keys deleted: {total_deleted_count}")


if __name__ == '__main__':
    main(sys.argv)
    

Run

python scan_and_unlink_pipe.py <host> <port> <password> "<key>" 

Parameters

Pattern syntax

Verify

redis-cli -h <host> -p <port> -a <password> --scan --pattern '<key>' | wc -l
# Expected output: 0

When to use

• Development or staging environments

• Databases with a small number of keys

• During complete service outages

Command

redis-cli -h <host> -p <port> -a <password> KEYS "<key>" | xargs redis-cli -h <host> -p <port> -a <password> DEL

Parameters

Pattern syntax

Example

redis-cli -h r-bp127cu5tb*****.redis.rds.aliyuncs.com -a Test**** KEYS "test*" | xargs redis-cli -h r-bp127cu5tb*****.redis.rds.aliyuncs.com -a Test**** DEL

Verify

redis-cli -h <host> -p <port> -a <password> --scan --pattern '<key>' | wc -l
# Expected output: 0