Frozen indices are deprecated which makes all the [SQL features supporting frozen indices](https://www.elastic.co/guide/en/elasticsearch/reference/current/sql-index-frozen.html) obsolete.

This includes:

* `index_include_frozen` request parameter in the `_sql` endpoint
* `index.include.frozen` (J|O)DBC driver settings
* `SHOW TABLES INCLUDE FROZEN` queries and the `FROZEN INDEX` kind in the corresponding response
* The `FROZEN` modifier in `FROM` clauses (as in `SELECT * FROM FROZEN archive`)

`_search` raises a deprecation warning when frozen indices are being searched with `ignore_throttled=false`. SQL could do the same when the `index_include_frozen` request parameter is set or when the `FROZEN` keyword is used.

Relates to https://github.com/elastic/elasticsearch/issues/70192
x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/parser/CommandBuilder.java
return new ShowSchemas(source(ctx));
    }
    @Override
    public Object visitShowColumns(ShowColumnsContext ctx) {
        TableIdentifier ti = visitTableIdentifier(ctx.tableIdent);
        String index = ti != null ? ti.qualifiedIndex() : null;
        return new ShowColumns(source(ctx), string(ctx.cluster), index, visitLikePattern(ctx.tableLike), ctx.FROZEN() != null);
    }
    @Override
    public Object visitShowCatalogs(ShowCatalogsContext ctx) {
        return new ShowCatalogs(source(ctx));
    }
    @Override
    public SysTables visitSysTables(SysTablesContext ctx) {
        List<IndexType> types = new ArrayList<>();
        for (StringContext string : ctx.string()) {
            String value = string(string);
            if (Strings.isEmpty(value) == false) {
                
                if (value.equals(StringUtils.SQL_WILDCARD) && ctx.string().size() == 1) {
                    
                    
                } else {
                    switch (value.toUpperCase(Locale.ROOT)) {
                        case IndexResolver.SQL_TABLE -> types.add(IndexType.STANDARD_INDEX);
                        case IndexResolver.SQL_VIEW -> types.add(IndexType.ALIAS);
                        default -> types.add(IndexType.UNKNOWN);
                    }
                }
            }