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alternator: add basic LSI support

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With this patch, LocalSecondaryIndexes can be added to a table
during its creation. The implementation is heavily shared
with GlobalSecondaryIndexes and as such suffers from the same TODOs:
projections, describing more details in DescribeTable, etc.
This commit is contained in:
Piotr Sarna
2019-08-28 09:16:03 +02:00
parent c46458f61d
commit a2d68eac4c
1 changed files with 73 additions and 10 deletions
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83
alternator/executor.cc
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@@ -117,13 +117,13 @@ static void validate_table_name(const std::string& name) {
// In DynamoDB index names are local to a table, while in Scylla, materialized
// view names are global (in a keyspace). So we need to compose a unique name
// for the view taking into account both the table's name and the index name.
// We concatenate the table and index name separated by a ":" character
// (a character not allowed by DynamoDB in ordinary table names).
// We concatenate the table and index name separated by a delim character
// (a character not allowed by DynamoDB in ordinary table names, default: ":").
// The downside of this approach is that it limits the sum of the lengths,
// instead of each component individually as DynamoDB does.
// The view_name() function assumes the table_name has already been validated
// but validates the legality of index_name and the combination of both.
static std::string view_name(const std::string& table_name, const std::string& index_name) {
static std::string view_name(const std::string& table_name, const std::string& index_name, const std::string& delim = ":") {
static const std::regex valid_index_name_chars ("[a-zA-Z0-9_.-]*");
if (index_name.length() < 3) {
throw api_error("ValidationException", "IndexName must be at least 3 characters long");
@@ -132,15 +132,19 @@ static std::string view_name(const std::string& table_name, const std::string& i
throw api_error("ValidationException",
format("IndexName '{}' must satisfy regular expression pattern: [a-zA-Z0-9_.-]+", index_name));
}
std::string ret = table_name + ":" + index_name;
std::string ret = table_name + delim + index_name;
if (ret.length() > max_table_name_length) {
throw api_error("ValidationException",
format("The total length of TableName ('{}') and IndexName ('{}') cannot exceed {} characters",
table_name, index_name, max_table_name_length - 1));
table_name, index_name, max_table_name_length - delim.size()));
}
return ret;
}
static std::string lsi_name(const std::string& table_name, const std::string& index_name) {
return view_name(table_name, index_name, "!:");
}
/** Extract table name from a request.
* Most requests expect the table's name to be listed in a "TableName" field.
* This convenience function returns the name, with appropriate validation
@@ -193,6 +197,12 @@ static schema_ptr get_table_or_view(service::storage_proxy& proxy, const rjson::
format("Non-string IndexName '{}'", index_name->GetString()));
}
}
// If no tables for global indexes were found, the index may be local
if (!proxy.get_db().local().has_schema(executor::KEYSPACE_NAME, table_name)) {
table_name = lsi_name(orig_table_name, index_name->GetString());
}
try {
return proxy.get_db().local().find_schema(executor::KEYSPACE_NAME, table_name);
} catch(no_such_column_family&) {
@@ -252,7 +262,8 @@ future<json::json_return_type> executor::describe_table(client_state& client_sta
rjson::set(table_description, "TableStatus", "ACTIVE");
table& t = _proxy.get_db().local().find_column_family(schema);
if (!t.views().empty()) {
rjson::value views_array = rjson::empty_array();
rjson::value gsi_array = rjson::empty_array();
rjson::value lsi_array = rjson::empty_array();
for (const view_ptr& vptr : t.views()) {
rjson::value view_entry = rjson::empty_object();
const sstring& cf_name = vptr->cf_name();
@@ -263,9 +274,16 @@ future<json::json_return_type> executor::describe_table(client_state& client_sta
}
sstring index_name = cf_name.substr(delim_it + 1);
rjson::set(view_entry, "IndexName", rjson::from_string(index_name));
rjson::push_back(views_array, std::move(view_entry));
// Local secondary indexes are marked by an extra '!' sign occurring before the ':' delimiter
rjson::value& index_array = (delim_it > 1 && cf_name[delim_it-1] == '!') ? lsi_array : gsi_array;
rjson::push_back(index_array, std::move(view_entry));
}
if (!lsi_array.Empty()) {
rjson::set(table_description, "LocalSecondaryIndexes", std::move(lsi_array));
}
if (!gsi_array.Empty()) {
rjson::set(table_description, "GlobalSecondaryIndexes", std::move(gsi_array));
}
rjson::set(table_description, "GlobalSecondaryIndexes", std::move(views_array));
}
// FIXME: more attributes! Check https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_TableDescription.html#DDB-Type-TableDescription-TableStatus but also run a test to see what DyanmoDB really fills
@@ -465,8 +483,53 @@ future<json::json_return_type> executor::create_table(client_state& client_state
}
}
if (rjson::find(table_info, "LocalSecondaryIndexes")) {
throw api_error("ValidationException", "LocalSecondaryIndexes: not yet supported.");
const rjson::value* lsi = rjson::find(table_info, "LocalSecondaryIndexes");
if (lsi) {
if (!lsi->IsArray()) {
throw api_error("ValidationException", "LocalSecondaryIndexes must be an array.");
}
for (const rjson::value& l : lsi->GetArray()) {
const rjson::value* index_name = rjson::find(l, "IndexName");
if (!index_name || !index_name->IsString()) {
throw api_error("ValidationException", "LocalSecondaryIndexes IndexName must be a string.");
}
std::string vname(lsi_name(table_name, index_name->GetString()));
elogger.trace("Adding LSI {}", index_name->GetString());
// FIXME: read and handle "Projection" parameter. This will
// require the MV code to copy just parts of the attrs map.
schema_builder view_builder(KEYSPACE_NAME, vname);
auto [view_hash_key, view_range_key] = parse_key_schema(l);
if (view_hash_key != hash_key) {
throw api_error("ValidationException", "LocalSecondaryIndex hash key must match the base table hash key");
}
add_column(view_builder, view_hash_key, attribute_definitions, column_kind::partition_key);
if (view_range_key.empty()) {
throw api_error("ValidationException", "LocalSecondaryIndex must specify a sort key");
}
if (view_range_key == hash_key) {
throw api_error("ValidationException", "LocalSecondaryIndex sort key cannot be the same as hash key");
}
if (view_range_key != range_key) {
add_column(builder, view_range_key, attribute_definitions, column_kind::regular_column);
}
add_column(view_builder, view_range_key, attribute_definitions, column_kind::clustering_key);
// Base key columns which aren't part of the index's key need to
// be added to the view nontheless, as (additional) clustering
// key(s).
if (!range_key.empty() && view_range_key != range_key) {
add_column(view_builder, range_key, attribute_definitions, column_kind::clustering_key);
}
view_builder.with_column(bytes(ATTRS_COLUMN_NAME), attrs_type(), column_kind::regular_column);
// Note above we don't need to add virtual columns, as all
// base columns were copied to view. TODO: reconsider the need
// for virtual columns when we support Projection.
sstring where_clause = "\"" + view_hash_key + "\" IS NOT NULL";
if (!view_range_key.empty()) {
where_clause = where_clause + " AND \"" + view_range_key + "\" IS NOT NULL";
}
where_clauses.push_back(std::move(where_clause));
view_builders.emplace_back(std::move(view_builder));
}
}
if (rjson::find(table_info, "SSESpecification")) {
throw api_error("ValidationException", "SSESpecification: configuring encryption-at-rest is not yet supported.");