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144 lines
4.1 KiB
C++
144 lines
4.1 KiB
C++
#include <Storages/System/StorageSystemMergeTreeMetadataCache.h>
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#if USE_ROCKSDB
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#include <DataTypes/DataTypeDateTime.h>
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#include <DataTypes/DataTypeString.h>
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#include <DataTypes/DataTypesNumber.h>
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#include <Interpreters/Context.h>
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#include <Parsers/ASTExpressionList.h>
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#include <Parsers/ASTFunction.h>
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#include <Parsers/ASTIdentifier.h>
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#include <Parsers/ASTLiteral.h>
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#include <Parsers/ASTSelectQuery.h>
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#include <Storages/MergeTree/KeyCondition.h>
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#include <Storages/MergeTree/MergeTreeMetadataCache.h>
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#include <Common/typeid_cast.h>
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int BAD_ARGUMENTS;
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}
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NamesAndTypesList StorageSystemMergeTreeMetadataCache::getNamesAndTypes()
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{
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return {
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{"key", std::make_shared<DataTypeString>()},
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{"value", std::make_shared<DataTypeString>()},
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};
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}
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static bool extractKeyImpl(const IAST & elem, String & res, bool & precise)
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{
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const auto * function = elem.as<ASTFunction>();
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if (!function)
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return false;
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if (function->name == "and")
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{
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for (const auto & child : function->arguments->children)
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{
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bool tmp_precise = false;
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if (extractKeyImpl(*child, res, tmp_precise))
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{
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precise = tmp_precise;
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return true;
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}
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}
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return false;
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}
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if (function->name == "equals" || function->name == "like")
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{
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const auto & args = function->arguments->as<ASTExpressionList &>();
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const IAST * value;
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if (args.children.size() != 2)
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return false;
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const ASTIdentifier * ident;
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if ((ident = args.children.at(0)->as<ASTIdentifier>()))
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value = args.children.at(1).get();
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else if ((ident = args.children.at(1)->as<ASTIdentifier>()))
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value = args.children.at(0).get();
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else
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return false;
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if (ident->name() != "key")
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return false;
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const auto * literal = value->as<ASTLiteral>();
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if (!literal)
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return false;
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if (literal->value.getType() != Field::Types::String)
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return false;
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res = literal->value.safeGet<String>();
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precise = function->name == "equals";
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return true;
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}
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return false;
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}
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/// Retrieve from the query a condition of the form `key= 'key'`, from conjunctions in the WHERE clause.
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static String extractKey(const ASTPtr & query, bool& precise)
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{
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const auto & select = query->as<ASTSelectQuery &>();
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if (!select.where())
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return "";
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String res;
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return extractKeyImpl(*select.where(), res, precise) ? res : "";
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}
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void StorageSystemMergeTreeMetadataCache::fillData(MutableColumns & res_columns, ContextPtr context, const SelectQueryInfo & query_info) const
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{
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bool precise = false;
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String key = extractKey(query_info.query, precise);
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if (key.empty())
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throw Exception(
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"SELECT from system.merge_tree_metadata_cache table must contain condition like key = 'key' or key LIKE 'prefix%' in WHERE clause.", ErrorCodes::BAD_ARGUMENTS);
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auto cache = context->getMergeTreeMetadataCache();
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if (precise)
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{
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String value;
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if (cache->get(key, value) != MergeTreeMetadataCache::Status::OK())
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return;
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size_t col_num = 0;
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res_columns[col_num++]->insert(key);
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res_columns[col_num++]->insert(value);
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}
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else
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{
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String target = extractFixedPrefixFromLikePattern(key);
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if (target.empty())
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throw Exception(
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"SELECT from system.merge_tree_metadata_cache table must contain condition like key = 'key' or key LIKE 'prefix%' in WHERE clause.", ErrorCodes::BAD_ARGUMENTS);
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Strings keys;
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Strings values;
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keys.reserve(4096);
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values.reserve(4096);
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cache->getByPrefix(target, keys, values);
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if (keys.empty())
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return;
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assert(keys.size() == values.size());
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for (size_t i = 0; i < keys.size(); ++i)
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{
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size_t col_num = 0;
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res_columns[col_num++]->insert(keys[i]);
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res_columns[col_num++]->insert(values[i]);
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}
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}
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}
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}
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#endif
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