sstablescrub¶
Fix a broken sstable. The scrub process rewrites the sstable, skipping any corrupted rows. Because these rows are lost, follow this process with a repair.
ref: https://issues.apache.org/jira/browse/CASSANDRA-4321
Cassandra must be stopped before this tool is executed, or unexpected results will occur. Note: the script does not verify that Cassandra is stopped.
Usage¶
sstablescrub <options> <keyspace> <table>
| –debug | display stack traces |
| -h,–help | display this help message |
| -m,–manifest-check | only check and repair the leveled manifest, without actually scrubbing the sstables |
| -n,–no-validate | do not validate columns using column validator |
| -r,–reinsert-overflowed-ttl | Rewrites rows with overflowed expiration date affected by CASSANDRA-14092 with the maximum supported expiration date of 2038-01-19T03:14:06+00:00. The rows are rewritten with the original timestamp incremented by one millisecond to override/supersede any potential tombstone that may have been generated during compaction of the affected rows. |
| -s,–skip-corrupted | skip corrupt rows in counter tables |
| -v,–verbose | verbose output |
Basic Scrub¶
The scrub without options will do a snapshot first, then write all non-corrupted files to a new sstable.
Example:
sstablescrub keyspace1 standard1
Pre-scrub sstables snapshotted into snapshot pre-scrub-1534424070883
Scrubbing BigTableReader(path='/var/lib/cassandra/data/keyspace1/standard1-6365332094dd11e88f324f9c503e4753/mc-5-big-Data.db') (17.142MiB)
Scrub of BigTableReader(path='/var/lib/cassandra/data/keyspace1/standard1-6365332094dd11e88f324f9c503e4753/mc-5-big-Data.db') complete: 73367 rows in new sstable and 0 empty (tombstoned) rows dropped
Checking leveled manifest
Scrub without Validation¶
ref: https://issues.apache.org/jira/browse/CASSANDRA-9406
Use the –no-validate option to retain data that may be misrepresented (e.g., an integer stored in a long field) but not corrupt. This data usually doesn not present any errors to the client.
Example:
sstablescrub --no-validate keyspace1 standard1
Pre-scrub sstables snapshotted into snapshot pre-scrub-1536243158517
Scrubbing BigTableReader(path='/var/lib/cassandra/data/keyspace1/standard1-bc9cf530b1da11e886c66d2c86545d91/mc-2-big-Data.db') (4.482MiB)
Scrub of BigTableReader(path='/var/lib/cassandra/data/keyspace1/standard1-bc9cf530b1da11e886c66d2c86545d91/mc-2-big-Data.db') complete; looks like all 0 rows were tombstoned
Skip Corrupted Counter Tables¶
ref: https://issues.apache.org/jira/browse/CASSANDRA-5930
If counter tables are corrupted in a way that prevents sstablescrub from completing, you can use the –skip-corrupted option to skip scrubbing those counter tables. This workaround is not necessary in versions 2.0+.
Example:
sstablescrub --skip-corrupted keyspace1 counter1
Dealing with Overflow Dates¶
ref: https://issues.apache.org/jira/browse/CASSANDRA-14092
Using the option –reinsert-overflowed-ttl allows a rewriting of rows that had a max TTL going over the maximum (causing an overflow).
Example:
sstablescrub --reinsert-overflowed-ttl keyspace1 counter1
Manifest Check¶
As of Cassandra version 2.0, this option is no longer relevant, since level data was moved from a separate manifest into the sstable metadata.