[CASSANDRA-19747] Invalid schema.cql created by snapshot after dropping more than one field

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 4.0.14, 4.1.6, 5.0-rc1, 5.1-alpha1
• Component/s: Local/Snapshots
• Bug Category: Correctness - Recoverable Corruption / Loss
• Severity: Normal
• Complexity: Normal
• Discovered By: User Report
• Platform: All
• Since Version: 4.0-beta1

Source Control Link

https://github.com/apache/cassandra/commit/a5767a58343f7c954e2a5bdb36811f909483dd97

Test and Documentation Plan

CI

• Assignee: Stefan Miklosovic
• Reporter: Frank vissing

Authors

Stefan Miklosovic

Reviewers

Benjamin Lerer, Francisco Guerrero

• Created: 03/Jul/24 09:40
• Updated: 10/Jul/24 10:17
• Resolved: 10/Jul/24 09:30

Description

After dropping at least 2 fields the schema.cql produced by nodetool snapshot is invalid (it is missing a comma)

CREATE TABLE IF NOT EXISTS test.testtable (
    field1 text PRIMARY KEY,
    field2 text
    field3 text
) WITH ID ...

expected outcome

CREATE TABLE IF NOT EXISTS test.testtable (
    field1 text PRIMARY KEY,
    field2 text,
    field3 text
) WITH ID ...

reproducing the isue is simple by running the following commands

docker run -d --name cassandra cassandra:4.1.5

echo "Wait for the container to start"
until docker exec -ti cassandra nodetool status | grep UN;do sleep 1;done;sleep 10

echo "Create keyspace and table for test"
docker exec -ti cassandra cqlsh -e "CREATE KEYSPACE IF NOT EXISTS test WITH replication = {'class': 'SimpleStrategy', 'replication_factor': '1'}; CREATE TABLE IF NOT EXISTS test.testtable (field1 text PRIMARY KEY,field2 text,field3 text);"

echo "Drop 2 fields"
docker exec -ti cassandra cqlsh -e "ALTER TABLE test.testtable DROP (field2, field3);"

echo "Create snapshot and view schema.cql"
docker exec -ti cassandra /opt/cassandra/bin/nodetool snapshot -t my_snapshot
docker exec -ti cassandra find /var/lib/cassandra/data -name schema.cql  -exec cat {} +   

the full output of the sql generated by the reproduce is below

CREATE TABLE IF NOT EXISTS test.testtable (
    field1 text PRIMARY KEY,
    field2 text
    field3 text
) WITH ID = 0e9aa540-391f-11ef-945e-0be1221ff441
    AND additional_write_policy = '99p'
    AND bloom_filter_fp_chance = 0.01
    AND caching = {'keys': 'ALL', 'rows_per_partition': 'NONE'}
    AND cdc = false
    AND comment = ''
    AND compaction = {'class': 'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy', 'max_threshold': '32', 'min_threshold': '4'}
    AND compression = {'chunk_length_in_kb': '16', 'class': 'org.apache.cassandra.io.compress.LZ4Compressor'}
    AND memtable = 'default'
    AND crc_check_chance = 1.0
    AND default_time_to_live = 0
    AND extensions = {}
    AND gc_grace_seconds = 864000
    AND max_index_interval = 2048
    AND memtable_flush_period_in_ms = 0
    AND min_index_interval = 128
    AND read_repair = 'BLOCKING'
    AND speculative_retry = '99p';
ALTER TABLE test.testtable DROP field2 USING TIMESTAMP 1719999102807000;
ALTER TABLE test.testtable DROP field3 USING TIMESTAMP 1719999102807001;

Found this bug while trying to restore the schema from a backup created by copying a snapshot from a running node.

Issue Links

• links to: GitHub Pull Request #3401
• links to: GitHub Pull Request #3402