28906c9261
The scylla-sstable dump-* command suite has proven invaluable in many investigations. In certain cases however, I found that `dump-data` is quite cumbersome. An example would be trying to find certain values in an sstable, or trying to read the content of system tables when a node is down. For these cases, `dump-data` is very cumbersome: one has to trudge through tons of uninteresting metadata and do compaction in their heads. This PR introduces the new scylla-sstable query command, specifically targeted at situations like this: it allows executing queries on sstables, exposing to the user all the power of CQL, to tailor the output as they see fit.
Select everything from a table:
$ scylla sstable query --system-schema /path/to/data/system_schema/keyspaces-*/*-big-Data.db
keyspace_name | durable_writes | replication
-------------------------------+----------------+-------------------------------------------------------------------------------------
system_replicated_keys | true | ({class : org.apache.cassandra.locator.EverywhereStrategy})
system_auth | true | ({class : org.apache.cassandra.locator.SimpleStrategy}, {replication_factor : 1})
system_schema | true | ({class : org.apache.cassandra.locator.LocalStrategy})
system_distributed | true | ({class : org.apache.cassandra.locator.SimpleStrategy}, {replication_factor : 3})
system | true | ({class : org.apache.cassandra.locator.LocalStrategy})
ks | true | ({class : org.apache.cassandra.locator.NetworkTopologyStrategy}, {datacenter1 : 1})
system_traces | true | ({class : org.apache.cassandra.locator.SimpleStrategy}, {replication_factor : 2})
system_distributed_everywhere | true | ({class : org.apache.cassandra.locator.EverywhereStrategy})
Select everything from a single SSTable, use the JSON output (filtered through [jq](https://jqlang.github.io/jq/) for better readability):
$ scylla sstable query --system-schema --output-format=json /path/to/data/system_schema/keyspaces-*/me-3gm7_127s_3ndxs28xt4llzxwqz6-big-Data.db | jq
[
{
"keyspace_name": "system_schema",
"durable_writes": true,
"replication": {
"class": "org.apache.cassandra.locator.LocalStrategy"
}
},
{
"keyspace_name": "system",
"durable_writes": true,
"replication": {
"class": "org.apache.cassandra.locator.LocalStrategy"
}
}
]
Select a specific field in a specific partition using the command-line:
$ scylla sstable query --system-schema --query "select replication from scylla_sstable.keyspaces where keyspace_name='ks'" ./scylla-workdir/data/system_schema/keyspaces-*/*-Data.db
replication
-------------------------------------------------------------------------------------
({class : org.apache.cassandra.locator.NetworkTopologyStrategy}, {datacenter1 : 1})
Select a specific field in a specific partition using ``--query-file``:
$ echo "SELECT replication FROM scylla_sstable.keyspaces WHERE keyspace_name='ks';" > query.cql
$ scylla sstable query --system-schema --query-file=./query.cql ./scylla-workdir/data/system_schema/keyspaces-*/*-Data.db
replication
-------------------------------------------------------------------------------------
({class : org.apache.cassandra.locator.NetworkTopologyStrategy}, {datacenter1 : 1})
New functionality: no backport needed.
Closes scylladb/scylladb#22007
* github.com:scylladb/scylladb:
docs/operating-scylla: document scylla-sstable query
test/cqlpy/test_tools.py: add tests for scylla-sstable query
test/cqlpy/test_tools.py: make scylla_sstable() return table name also
scylla-sstable: introduce the query command
tools/utils: get_selected_operation(): use std::string for operation_options
utils/rjson: streaming_writer: add RawValue()
cql3/type_json: add to_json_type()
test/lib/cql_test_env: introduce do_with_cql_env_noreentrant_in_thread()
10 KiB
10 KiB