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d2c5268196
Before this change, executing `DESCRIBE MATERIALIZED VIEW` on the underlying
materialized view of a secondary index would produce a `CREATE INDEX` statement.
It was not only confusing, but it also prevented from learning about
the definition of the view. The only way to do so was to query system tables.
We change that behavior and produce a `CREATE MATERIALIZED VIEW` statement
instead. The statement is printed as a comment to implicitly convey that
the user should not attempt to execute it to restore the view. A short comment
is provided to make it clearer.
Before this commit:
```
cqlsh> CREATE TABLE ks.t(p int PRIMARY KEY, v int);
cqlsh> CREATE INDEX i ON ks.t(v);
cqlsh> DESCRIBE MATERIALIZED VIEW ks.i;
CREATE INDEX i ON ks.t(v);
```
After this commit:
```
cqlsh> CREATE TABLE ks.t(p int PRIMARY KEY, v int);
cqlsh> CREATE INDEX i ON ks.t(v);
cqlsh> DESCRIBE MATERIALIZED VIEW ks.i;
/* Do NOT execute this statement! It's only for informational purposes.
This materialized view is the underlying materialized view of a secondary
index. It can be restored via restoring the index.
CREATE MATERIALIZED VIEW ks.i_index [...];
*/
```
Note that describing the base table has not been affected and still works
as follows:
```
cqlsh> CREATE TABLE ks.t(p int PRIMARY KEY, v int);
cqlsh> CREATE INDEX i ON ks.t(v);
cqlsh> DESCRIBE TABLE ks.t;
CREATE TABLE ks.t (
p int,
v int,
PRIMARY KEY (p)
) WITH bloom_filter_fp_chance = 0.01
AND caching = {'keys': 'ALL', 'rows_per_partition': 'ALL'}
AND comment = ''
AND compaction = {'class': 'IncrementalCompactionStrategy'}
AND compression = {'sstable_compression': 'org.apache.cassandra.io.compress.LZ4Compressor'}
AND crc_check_chance = 1
AND default_time_to_live = 0
AND gc_grace_seconds = 864000
AND max_index_interval = 2048
AND memtable_flush_period_in_ms = 0
AND min_index_interval = 128
AND speculative_retry = '99.0PERCENTILE'
AND tombstone_gc = {'mode': 'timeout', 'propagation_delay_in_seconds': '3600'};
CREATE INDEX i ON ks.t(v);
```
We also provide two reproducers of scylladb/scylladb#24610.
Fixes scylladb/scylladb#24610
Closes scylladb/scylladb#25697