Merge pull request #5003 from Enmk/geohash_support

Implementation of geohashEncode and geohashDecode functions;

dbms/src/DataTypes/IDataType.h

@@ -574,6 +574,13 @@ inline bool isInteger(const T & data_type)
     return which.isInt() || which.isUInt();
 }
 
+template <typename T>
+inline bool isFloat(const T & data_type)
+{
+    WhichDataType which(data_type);
+    return which.isFloat();
+}
+
 template <typename T>
 inline bool isNumber(const T & data_type)
 {

dbms/src/Functions/FunctionHelpers.cpp

 #include <Functions/FunctionHelpers.h>
+#include <Functions/IFunction.h>
 #include <Columns/ColumnTuple.h>
 #include <Columns/ColumnString.h>
 #include <Columns/ColumnFixedString.h>
@@ -13,6 +14,7 @@ namespace DB
 namespace ErrorCodes
 {
     extern const int ILLEGAL_COLUMN;
+    extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
 }
 
 const ColumnConst * checkAndGetColumnConstStringOrFixedString(const IColumn * column)
@@ -99,4 +101,21 @@ Block createBlockWithNestedColumns(const Block & block, const ColumnNumbers & ar
     return createBlockWithNestedColumnsImpl(block, args_set);
 }
 
+void validateArgumentType(const IFunction & func, const DataTypes & arguments,
+                                 size_t argument_index, bool (* validator_func)(const IDataType &),
+                                 const char * expected_type_description)
+{
+    if (arguments.size() <= argument_index)
+        throw Exception("Incorrect number of arguments of function " + func.getName(),
+                        ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
+
+    const auto & argument = arguments[argument_index];
+    if (validator_func(*argument) == false)
+        throw Exception("Illegal type " + argument->getName() +
+                        " of " + std::to_string(argument_index) +
+                        " argument of function " + func.getName() +
+                        " expected " + expected_type_description,
+                        ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
+}
+
 }

dbms/src/Functions/FunctionHelpers.h

@@ -12,6 +12,8 @@
 namespace DB
 {
 
+class IFunction;
+
 /// Methods, that helps dispatching over real column types.
 
 template <typename Type>
@@ -64,7 +66,6 @@ bool checkColumnConst(const IColumn * column)
     return checkAndGetColumnConst<Type>(column);
 }
 
-
 /// Returns non-nullptr if column is ColumnConst with ColumnString or ColumnFixedString inside.
 const ColumnConst * checkAndGetColumnConstStringOrFixedString(const IColumn * column);
 
@@ -94,4 +95,10 @@ Block createBlockWithNestedColumns(const Block & block, const ColumnNumbers & ar
 /// Similar function as above. Additionally transform the result type if needed.
 Block createBlockWithNestedColumns(const Block & block, const ColumnNumbers & args, size_t result);
 
+/// Checks argument type at specified index with predicate.
+/// throws if there is no argument at specified index or if predicate returns false.
+void validateArgumentType(const IFunction & func, const DataTypes & arguments,
+        size_t argument_index, bool (* validator_func)(const IDataType &),
+        const char * expected_type_description);
+
 }

dbms/src/Functions/FunctionsGeo.cpp

 #include <Functions/FunctionFactory.h>
 #include <Functions/FunctionsGeo.h>
 #include <Functions/GeoUtils.h>
+#include <Functions/FunctionHelpers.h>
 
 #include <boost/geometry.hpp>
 #include <boost/geometry/geometries/point_xy.hpp>
 #include <boost/geometry/geometries/polygon.hpp>
 
-#include <Interpreters/ExpressionActions.h>
-#include <DataTypes/DataTypeTuple.h>
-#include <Columns/ColumnTuple.h>
-#include <IO/WriteHelpers.h>
-#include <DataTypes/DataTypeArray.h>
 #include <Columns/ColumnArray.h>
-#include <Common/ProfileEvents.h>
+#include <Columns/ColumnFixedString.h>
+#include <Columns/ColumnString.h>
+#include <Columns/ColumnTuple.h>
 #include <Common/ObjectPool.h>
+#include <Common/ProfileEvents.h>
+#include <DataTypes/DataTypeArray.h>
+#include <DataTypes/DataTypeString.h>
+#include <DataTypes/DataTypeTuple.h>
+#include <IO/WriteHelpers.h>
+#include <Interpreters/ExpressionActions.h>
+
 #include <string>
 #include <memory>
 
@@ -246,6 +251,186 @@ private:
 
 };
 
+const size_t GEOHASH_MAX_TEXT_LENGTH = 16;
+
+// geohashEncode(lon float32/64, lat float32/64, length UInt8) => string
+class FunctionGeohashEncode : public IFunction
+{
+public:
+    static constexpr auto name = "geohashEncode";
+    static FunctionPtr create(const Context &) { return std::make_shared<FunctionGeohashEncode>(); }
+
+    String getName() const override
+    {
+        return name;
+    }
+
+    bool isVariadic() const override { return true; }
+    size_t getNumberOfArguments() const override { return 0; }
+    ColumnNumbers getArgumentsThatAreAlwaysConstant() const override { return {2}; }
+    bool useDefaultImplementationForConstants() const override { return true; }
+
+    DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
+    {
+        validateArgumentType(*this, arguments, 0, isFloat, "float");
+        validateArgumentType(*this, arguments, 1, isFloat, "float");
+        if (arguments.size() == 3)
+        {
+            validateArgumentType(*this, arguments, 2, isInteger, "integer");
+        }
+        if (arguments.size() > 3)
+        {
+            throw Exception("Too many arguments for function " + getName() +
+                            " expected at most 3",
+                            ErrorCodes::TOO_MANY_ARGUMENTS_FOR_FUNCTION);
+        }
+
+        return std::make_shared<DataTypeString>();
+    }
+
+    template <typename LonType, typename LatType>
+    bool tryExecute(const IColumn * lon_column, const IColumn * lat_column, UInt64 precision_value, ColumnPtr & result)
+    {
+        const ColumnVector<LonType> * longitude = checkAndGetColumn<ColumnVector<LonType>>(lon_column);
+        const ColumnVector<LatType> * latitude = checkAndGetColumn<ColumnVector<LatType>>(lat_column);
+        if (!latitude || !longitude)
+            return false;
+
+        auto col_str = ColumnString::create();
+        ColumnString::Chars & out_vec = col_str->getChars();
+        ColumnString::Offsets & out_offsets = col_str->getOffsets();
+
+        const size_t size = lat_column->size();
+
+        out_offsets.resize(size);
+        out_vec.resize(size * (GEOHASH_MAX_TEXT_LENGTH + 1));
+
+        char * begin = reinterpret_cast<char *>(out_vec.data());
+        char * pos = begin;
+
+        for (size_t i = 0; i < size; ++i)
+        {
+            const Float64 longitude_value = longitude->getElement(i);
+            const Float64 latitude_value = latitude->getElement(i);
+
+            const size_t encoded_size = GeoUtils::geohashEncode(longitude_value, latitude_value, precision_value, pos);
+
+            pos += encoded_size;
+            *pos = '\0';
+            out_offsets[i] = ++pos - begin;
+        }
+        out_vec.resize(pos - begin);
+
+        if (!out_offsets.empty() && out_offsets.back() != out_vec.size())
+            throw Exception("Column size mismatch (internal logical error)", ErrorCodes::LOGICAL_ERROR);
+
+        result = std::move(col_str);
+
+        return true;
+
+    }
+
+    void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t /*input_rows_count*/) override
+    {
+        const IColumn * longitude = block.getByPosition(arguments[0]).column.get();
+        const IColumn * latitude = block.getByPosition(arguments[1]).column.get();
+
+        const UInt64 precision_value = std::min(GEOHASH_MAX_TEXT_LENGTH,
+                arguments.size() == 3 ? block.getByPosition(arguments[2]).column->get64(0) : GEOHASH_MAX_TEXT_LENGTH);
+
+        ColumnPtr & res_column = block.getByPosition(result).column;
+
+        if (tryExecute<Float32, Float32>(longitude, latitude, precision_value, res_column) ||
+            tryExecute<Float64, Float32>(longitude, latitude, precision_value, res_column) ||
+            tryExecute<Float32, Float64>(longitude, latitude, precision_value, res_column) ||
+            tryExecute<Float64, Float64>(longitude, latitude, precision_value, res_column))
+            return;
+
+        const char sep[] = ", ";
+        std::string arguments_description = "";
+        for (size_t i = 0; i < arguments.size(); ++i)
+        {
+            arguments_description += block.getByPosition(arguments[i]).column->getName() + sep;
+        }
+        if (arguments_description.size() > sizeof(sep))
+        {
+            arguments_description.erase(arguments_description.size() - sizeof(sep) - 1);
+        }
+
+        throw Exception("Unsupported argument types: " + arguments_description +
+                        + " for function " + getName(),
+                        ErrorCodes::ILLEGAL_COLUMN);
+    }
+};
+
+// geohashDecode(string) => (lon float64, lat float64)
+class FunctionGeohashDecode : public IFunction
+{
+public:
+    static constexpr auto name = "geohashDecode";
+    static FunctionPtr create(const Context &) { return std::make_shared<FunctionGeohashDecode>(); }
+
+    String getName() const override
+    {
+        return name;
+    }
+
+    size_t getNumberOfArguments() const override { return 1; }
+    bool useDefaultImplementationForConstants() const override { return true; }
+
+    DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
+    {
+        validateArgumentType(*this, arguments, 0, isStringOrFixedString, "string or fixed string");
+
+        return std::make_shared<DataTypeTuple>(
+                DataTypes{std::make_shared<DataTypeFloat64>(), std::make_shared<DataTypeFloat64>()},
+                Strings{"longitude", "latitude"});
+    }
+
+    template <typename ColumnTypeEncoded>
+    bool tryExecute(const IColumn * encoded_column, ColumnPtr & result_column)
+    {
+        const auto * encoded = checkAndGetColumn<ColumnTypeEncoded>(encoded_column);
+        if (!encoded)
+            return false;
+
+        const size_t count = encoded->size();
+
+        auto latitude = ColumnFloat64::create(count);
+        auto longitude = ColumnFloat64::create(count);
+
+        ColumnFloat64::Container & lon_data = longitude->getData();
+        ColumnFloat64::Container & lat_data = latitude->getData();
+
+        for (size_t i = 0; i < count; ++i)
+        {
+            StringRef encoded_string = encoded->getDataAt(i);
+            GeoUtils::geohashDecode(encoded_string.data, encoded_string.size, &lon_data[i], &lat_data[i]);
+        }
+
+        MutableColumns result;
+        result.emplace_back(std::move(longitude));
+        result.emplace_back(std::move(latitude));
+        result_column = ColumnTuple::create(std::move(result));
+
+        return true;
+    }
+
+    void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t /*input_rows_count*/) override
+    {
+        const IColumn * encoded = block.getByPosition(arguments[0]).column.get();
+        ColumnPtr & res_column = block.getByPosition(result).column;
+
+        if (tryExecute<ColumnString>(encoded, res_column) ||
+            tryExecute<ColumnFixedString>(encoded, res_column))
+            return;
+
+        throw Exception("Unsupported argument type:" + block.getByPosition(arguments[0]).column->getName()
+                        + " of argument of function " + getName(),
+                        ErrorCodes::ILLEGAL_COLUMN);
+    }
+};
+
 template <typename Type>
 using Point = boost::geometry::model::d2::point_xy<Type>;
 
@@ -261,5 +446,7 @@ void registerFunctionsGeo(FunctionFactory & factory)
     factory.registerFunction<FunctionPointInEllipses>();
 
     factory.registerFunction<FunctionPointInPolygon<PointInPolygonWithGrid, true>>();
+    factory.registerFunction<FunctionGeohashEncode>();
+    factory.registerFunction<FunctionGeohashDecode>();
 }
 }

dbms/src/Functions/GeoUtils.cpp

+#include <Core/Types.h>
+#include <Functions/GeoUtils.h>
+
+namespace
+{
+
+using namespace DB;
+
+const char geohash_base32_encode_lookup_table[32] = {
+    '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+    'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k', 'm',
+    'n', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
+    'y', 'z',
+};
+
+// TODO: this could be halved by excluding 128-255 range.
+const UInt8 geohash_base32_decode_lookup_table[256] = {
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0,   1,     2,    3,    4,    5,    6,    7,    8,    9,    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 10,   11,   12,   13,   14,   15,   16,   0xFF, 17,   18,   0xFF, 19,   20,   0xFF,
+    21,   22,   23,   24,   25,   26,   27,   28,   29,   30,   31,   0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+};
+
+const size_t BITS_PER_SYMBOL = 5;
+const size_t MAX_PRECISION = 12;
+const size_t MAX_BITS = MAX_PRECISION * BITS_PER_SYMBOL * 1.5;
+
+using Encoded = std::array<UInt8, MAX_BITS>;
+
+enum CoordType
+{
+    LATITUDE,
+    LONGITUDE,
+};
+
+inline UInt8 singleCoordBitsPrecision(UInt8 precision, CoordType type)
+{
+    // Single coordinate occupies only half of the total bits.
+    const UInt8 bits = (precision * BITS_PER_SYMBOL) / 2;
+    if (precision & 0x1 && type == LONGITUDE)
+    {
+        return bits + 1;
+    }
+
+    return bits;
+}
+
+inline Encoded encodeCoordinate(Float64 coord, Float64 min, Float64 max, UInt8 bits)
+{
+    Encoded result;
+    result.fill(0);
+
+    for (int i = 0; i < bits; ++i)
+    {
+        Float64 mid = (max + min) / 2;
+        if (coord >= mid)
+        {
+            result[i] = 1;
+            min = mid;
+        }
+        else
+        {
+            result[i] = 0;
+            max = mid;
+        }
+    }
+
+    return result;
+}
+
+inline Float64 decodeCoordinate(const Encoded & coord, Float64 min, Float64 max, UInt8 bits)
+{
+    Float64 mid = (max + min) / 2;
+    for (int i = 0; i < bits; ++i)
+    {
+        const auto c = coord[i];
+        if (c == 1)
+        {
+            min = mid;
+        }
+        else
+        {
+            max = mid;
+        }
+
+        mid = (max + min) / 2;
+    }
+
+    return mid;
+}
+
+inline Encoded merge(const Encoded & encodedLon, const Encoded & encodedLat, UInt8 precision)
+{
+    Encoded result;
+    result.fill(0);
+
+    const auto bits = (precision * BITS_PER_SYMBOL) / 2;
+    UInt8 i = 0;
+    for (; i < bits; ++i)
+    {
+        result[i * 2 + 0] = encodedLon[i];
+        result[i * 2 + 1] = encodedLat[i];
+    }
+    // in case of even precision, add last bit of longitude
+    if (precision & 0x1)
+    {
+        result[i * 2] = encodedLon[i];
+    }
+
+    return result;
+}
+
+inline std::tuple<Encoded, Encoded> split(const Encoded & combined, UInt8 precision)
+{
+    Encoded lat, lon;
+    lat.fill(0);
+    lon.fill(0);
+
+    UInt8 i = 0;
+    for (; i < precision * BITS_PER_SYMBOL - 1; i += 2)
+    {
+        // longitude is even bits
+        lon[i/2] = combined[i];
+        lat[i/2] = combined[i + 1];
+    }
+    // precision is even, read the last bit as lat.
+    if (precision & 0x1)
+    {
+        lon[i/2] = combined[precision * BITS_PER_SYMBOL - 1];
+    }
+
+    return std::tie(lon, lat);
+}
+
+inline void base32Encode(const Encoded & binary, UInt8 precision, char * out)
+{
+    extern const char geohash_base32_encode_lookup_table[32];
+
+    for (UInt8 i = 0; i < precision * BITS_PER_SYMBOL; i += 5)
+    {
+        UInt8 v = binary[i];
+        v <<= 1;
+        v |= binary[i + 1];
+        v <<= 1;
+        v |= binary[i + 2];
+        v <<= 1;
+        v |= binary[i + 3];
+        v <<= 1;
+        v |= binary[i + 4];
+
+        assert(v < 32);
+
+        *out = geohash_base32_encode_lookup_table[v];
+        ++out;
+    }
+}
+
+inline Encoded base32Decode(const char * encoded_string, size_t encoded_length)
+{
+    extern const UInt8 geohash_base32_decode_lookup_table[256];
+
+    Encoded result;
+
+    for (size_t i = 0; i < encoded_length; ++i)
+    {
+        const UInt8 c = static_cast<UInt8>(encoded_string[i]);
+        const UInt8 decoded = geohash_base32_decode_lookup_table[c] & 0x1F;
+        result[i * 5 + 4] = (decoded >> 0) & 0x01;
+        result[i * 5 + 3] = (decoded >> 1) & 0x01;
+        result[i * 5 + 2] = (decoded >> 2) & 0x01;
+        result[i * 5 + 1] = (decoded >> 3) & 0x01;
+        result[i * 5 + 0] = (decoded >> 4) & 0x01;
+    }
+
+    return result;
+}
+
+} // namespace
+
+namespace DB
+{
+
+namespace GeoUtils
+{
+
+size_t geohashEncode(Float64 longitude, Float64 latitude, UInt8 precision, char *& out)
+{
+    if (precision == 0 || precision > MAX_PRECISION)
+    {
+        precision = MAX_PRECISION;
+    }
+
+    const Encoded combined = merge(
+                encodeCoordinate(longitude, -180, 180, singleCoordBitsPrecision(precision, LONGITUDE)),
+                encodeCoordinate(latitude, -90, 90, singleCoordBitsPrecision(precision, LATITUDE)),
+                precision);
+
+    base32Encode(combined, precision, out);
+
+    return precision;
+}
+
+void geohashDecode(const char * encoded_string, size_t encoded_len, Float64 * longitude, Float64 * latitude)
+{
+    const UInt8 precision = std::min(encoded_len, MAX_PRECISION);
+    if (precision == 0)
+    {
+        return;
+    }
+
+    Encoded lat_encoded, lon_encoded;
+    std::tie(lon_encoded, lat_encoded) = split(base32Decode(encoded_string, precision), precision);
+
+    *longitude = decodeCoordinate(lon_encoded, -180, 180, singleCoordBitsPrecision(precision, LONGITUDE));
+    *latitude = decodeCoordinate(lat_encoded, -90, 90, singleCoordBitsPrecision(precision, LATITUDE));
+}
+
+} // namespace GeoUtils
+
+} // namespace DB

dbms/src/Functions/GeoUtils.h

@@ -699,6 +699,10 @@ std::string serialize(Polygon && polygon)
     return result;
 }
 
+size_t geohashEncode(Float64 longitude, Float64 latitude, UInt8 precision, char *& out);
+
+void geohashDecode(const char * encoded_string, size_t encoded_len, Float64 * longitude, Float64 * latitude);
+
 
 } /// GeoUtils
 

dbms/tests/performance/funtions_geo/functions_geo.xml

+<test>
+    <name>functions_coding</name>
+    <type>once</type>
+
+    <stop_conditions>
+        <any_of>
+            <average_speed_not_changing_for_ms>300</average_speed_not_changing_for_ms>
+            <total_time_ms>1000</total_time_ms>
+        </any_of>
+    </stop_conditions>
+
+    <metrics>
+        <max_rows_per_second />
+        <max_bytes_per_second />
+        <avg_rows_per_second />
+        <avg_bytes_per_second />
+    </metrics>
+
+    <!-- lat swings roughly from -90 to 90, lon swings from -180 to 180, and their tempo does not match. -->
+    <query>SELECT count() FROM system.numbers WHERE NOT ignore(geohashEncode((number % 150)*1.1 - 75, (number * 3.14 % 300)*1.1 - 150))</query>
+    <query>SELECT count() FROM system.numbers WHERE NOT ignore(geohashDecode(toString(number % 1000000)))</query>
+
+    <query>SELECT count() FROM system.numbers WHERE NOT ignore(geohashEncode(1.0/rand(), 2.0/rand()))</query>
+    <query>SELECT count() FROM system.numbers WHERE NOT ignore(geohashDecode(toString(rand() % 1000000)))</query>
+
+    <!-- erroneus values -->
+    <query>SELECT count() FROM system.numbers WHERE NOT ignore(geohashEncode(number + 91.0, number + 181.0))</query>
+    <query>SELECT count() FROM system.numbers WHERE NOT ignore(geohashDecode(hex(number)))</query>
+</test>

dbms/tests/queries/0_stateless/00932_geohash_support.reference

+invalid values:
+zzzzzzzzzzzz
+000000000000
+1
+constant values:
+ezs42d000000
+-5.60303	42.60498
+default precision:
+ezs42d000000
+mixing const and non-const-columns:
+ezs42d000000
+from table (with const precision):
+1	6	Ok
+1	6	Ok
+1	6	Ok
+1	7	Ok
+1	7	Ok
+1	k	Ok
+1	k	Ok
+1	k	Ok
+1	7	Ok
+1	7	Ok
+1	k	Ok
+1	k	Ok
+1	k	Ok
+1	e	Ok
+1	e	Ok
+1	s	Ok
+1	s	Ok
+1	s	Ok
+1	e	Ok
+1	e	Ok
+1	s	Ok
+1	s	Ok
+1	s	Ok
+1	e	Ok
+1	e	Ok
+1	s	Ok
+1	s	Ok
+1	s	Ok
+1	w	Ok
+1	g	Ok
+1	u	Ok
+2	6g	Ok
+2	6g	Ok
+2	6g	Ok
+2	7z	Ok
+2	7z	Ok
+2	kp	Ok
+2	kp	Ok
+2	kp	Ok
+2	7z	Ok
+2	7z	Ok
+2	kp	Ok
+2	kp	Ok
+2	kp	Ok
+2	eb	Ok
+2	eb	Ok
+2	s0	Ok
+2	s0	Ok
+2	s0	Ok
+2	eb	Ok
+2	eb	Ok
+2	s0	Ok
+2	s0	Ok
+2	s0	Ok
+2	eb	Ok
+2	eb	Ok
+2	s0	Ok
+2	s0	Ok
+2	s0	Ok
+2	w1	Ok
+2	gc	Ok
+2	u9	Ok
+3	6gk	Ok
+3	6gk	Ok
+3	6gk	Ok
+3	7zz	Ok
+3	7zz	Ok
+3	kpb	Ok
+3	kpb	Ok
+3	kpb	Ok
+3	7zz	Ok
+3	7zz	Ok
+3	kpb	Ok
+3	kpb	Ok
+3	kpb	Ok
+3	ebp	Ok
+3	ebp	Ok
+3	s00	Ok
+3	s00	Ok
+3	s00	Ok
+3	ebp	Ok
+3	ebp	Ok
+3	s00	Ok
+3	s00	Ok
+3	s00	Ok
+3	ebp	Ok
+3	ebp	Ok
+3	s00	Ok
+3	s00	Ok
+3	s00	Ok
+3	w1m	Ok
+3	gcp	Ok
+3	u9e	Ok
+4	6gkz	Ok
+4	6gkz	Ok
+4	6gkz	Ok
+4	7zzz	Ok
+4	7zzz	Ok
+4	kpbp	Ok
+4	kpbp	Ok
+4	kpbp	Ok
+4	7zzz	Ok
+4	7zzz	Ok
+4	kpbp	Ok
+4	kpbp	Ok
+4	kpbp	Ok
+4	ebpb	Ok
+4	ebpb	Ok
+4	s000	Ok
+4	s000	Ok
+4	s000	Ok
+4	ebpb	Ok
+4	ebpb	Ok
+4	s000	Ok
+4	s000	Ok
+4	s000	Ok
+4	ebpb	Ok
+4	ebpb	Ok
+4	s000	Ok
+4	s000	Ok
+4	s000	Ok
+4	w1mu	Ok
+4	gcpv	Ok
+4	u9ed	Ok
+5	6gkzm	Ok
+5	6gkzw	Ok
+5	6gkzw	Ok
+5	7zzzm	Ok
+5	7zzzr	Ok
+5	kpbp2	Ok
+5	kpbp2	Ok
+5	kpbp6	Ok
+5	7zzzv	Ok
+5	7zzzz	Ok
+5	kpbpb	Ok
+5	kpbpb	Ok
+5	kpbpf	Ok
+5	ebpbj	Ok
+5	ebpbp	Ok
+5	s0000	Ok
+5	s0004	Ok
+5	ebpbj	Ok
+5	ebpbp	Ok
+5	s0000	Ok
+5	s0000	Ok
+5	s0004	Ok
+5	ebpbt	Ok
+5	ebpbx	Ok
+5	s0008	Ok
+5	s0008	Ok
+5	s000d	Ok
+5	w1muy	Ok
+5	gcpvn	Ok
+5	u9edu	Ok
+6	6gkzmg	Ok
+6	6gkzwg	Ok
+6	6gkzwg	Ok
+6	7zzzrv	Ok
+6	kpbp2j	Ok
+6	7zzzvw	Ok
+6	7zzzzy	Ok
+6	kpbpbn	Ok
+6	kpbpbn	Ok
+6	kpbpfq	Ok
+6	ebpbpb	Ok
+6	s00000	Ok
+6	ebpbj9	Ok
+6	ebpbpc	Ok
+6	s00001	Ok
+6	s00001	Ok
+6	s00043	Ok
+6	ebpbxf	Ok
+6	s00084	Ok
+6	w1muy6	Ok
+6	gcpvn5	Ok
+6	u9edu0	Ok
+7	6gkzmg1	Ok
+7	6gkzwgj	Ok
+7	6gkzwgj	Ok
+7	7zzzrvb	Ok
+7	kpbp2jz	Ok
+7	7zzzzy0	Ok
+7	kpbpbnp	Ok
+7	ebpbpb0	Ok
+7	s00000p	Ok
+7	ebpbpcb	Ok
+7	s00001z	Ok
+7	ebpbxf0	Ok
+7	s00084p	Ok
+7	w1muy6d	Ok
+7	gcpvn5w	Ok
+7	u9edu0q	Ok
+8	6gkzmg1u	Ok
+8	6gkzwgjt	Ok
+8	6gkzwgjz	Ok
+8	w1muy6dt	Ok
+8	gcpvn5w2	Ok
+8	u9edu0qs	Ok
+9	6gkzwgjzn	Ok
+9	w1muy6dt2	Ok
+9	gcpvn5w2e	Ok
+9	u9edu0qsf	Ok
+10	6gkzwgjzn8	Ok
+10	w1muy6dt2p	Ok
+10	gcpvn5w2eu	Ok
+10	u9edu0qsf7	Ok
+11	6gkzwgjzn82	Ok
+11	w1muy6dt2pt	Ok
+11	gcpvn5w2euk	Ok
+11	u9edu0qsf7d	Ok
+12	6gkzwgjzn820	Ok
+12	w1muy6dt2ptk	Ok
+12	gcpvn5w2euky	Ok
+12	u9edu0qsf7dn	Ok
+incorrectly decoded values:

dbms/tests/queries/0_stateless/00932_geohash_support.sql

+drop table if exists geohash_test_data;
+
+create table geohash_test_data (
+	latitude  Float64,
+	longitude Float64,
+	encoded   String
+) engine = MergeTree order by (latitude, longitude, encoded);
+
+-- data obtained from geohash.com
+insert into geohash_test_data values (-25.427, -49.315, '6'), (-25.427, -49.315, '6g'), (-25.427, -49.315, '6gk'), (-25.427, -49.315, '6gkz'), (-25.427, -49.315, '6gkzm'), (-25.427, -49.315, '6gkzmg'), (-25.427, -49.315, '6gkzmg1'), (-25.427, -49.315, '6gkzmg1u'), (-25.383, -49.266, '6'), (-25.383, -49.266, '6g'), (-25.383, -49.266, '6gk'), (-25.383, -49.266, '6gkz'), (-25.383, -49.266, '6gkzw'), (-25.383, -49.266, '6gkzwg'), (-25.383, -49.266, '6gkzwgj'), (-25.383, -49.266, '6gkzwgjt'), (-25.382708, -49.265506, '6'), (-25.382708, -49.265506, '6g'), (-25.382708, -49.265506, '6gk'), (-25.382708, -49.265506, '6gkz'), (-25.382708, -49.265506, '6gkzw'), (-25.382708, -49.265506, '6gkzwg'), (-25.382708, -49.265506, '6gkzwgj'), (-25.382708, -49.265506, '6gkzwgjz'), (-25.382708, -49.265506, '6gkzwgjzn'), (-25.382708, -49.265506, '6gkzwgjzn8'), (-25.382708, -49.265506, '6gkzwgjzn82'), (-25.382708, -49.265506, '6gkzwgjzn820'), (-0.1, -0.1, '7'), (-0.1, -0.1, '7z'), (-0.1, -0.1, '7zz'), (-0.1, -0.1, '7zzz'), (-0.1, -0.1, '7zzzm'), (-0.1, -0.01, '7'), (-0.1, -0.01, '7z'), (-0.1, -0.01, '7zz'), (-0.1, -0.01, '7zzz'), (-0.1, -0.01, '7zzzr'), (-0.1, -0.01, '7zzzrv'), (-0.1, -0.01, '7zzzrvb'), (-0.1, 0, 'k'), (-0.1, 0, 'kp'), (-0.1, 0, 'kpb'), (-0.1, 0, 'kpbp'), (-0.1, 0, 'kpbp2'), (-0.1, 0.01, 'k'), (-0.1, 0.01, 'kp'), (-0.1, 0.01, 'kpb'), (-0.1, 0.01, 'kpbp'), (-0.1, 0.01, 'kpbp2'), (-0.1, 0.01, 'kpbp2j'), (-0.1, 0.01, 'kpbp2jz'), (-0.1, 0.1, 'k'), (-0.1, 0.1, 'kp'), (-0.1, 0.1, 'kpb'), (-0.1, 0.1, 'kpbp'), (-0.1, 0.1, 'kpbp6'), (-0.01, -0.1, '7'), (-0.01, -0.1, '7z'), (-0.01, -0.1, '7zz'), (-0.01, -0.1, '7zzz'), (-0.01, -0.1, '7zzzv'), (-0.01, -0.1, '7zzzvw'), (-0.01, -0.01, '7'), (-0.01, -0.01, '7z'), (-0.01, -0.01, '7zz'), (-0.01, -0.01, '7zzz'), (-0.01, -0.01, '7zzzz'), (-0.01, -0.01, '7zzzzy'), (-0.01, -0.01, '7zzzzy0'), (-0.01, 0, 'k'), (-0.01, 0, 'kp'), (-0.01, 0, 'kpb'), (-0.01, 0, 'kpbp'), (-0.01, 0, 'kpbpb'), (-0.01, 0, 'kpbpbn'), (-0.01, 0.01, 'k'), (-0.01, 0.01, 'kp'), (-0.01, 0.01, 'kpb'), (-0.01, 0.01, 'kpbp'), (-0.01, 0.01, 'kpbpb'), (-0.01, 0.01, 'kpbpbn'), (-0.01, 0.01, 'kpbpbnp'), (-0.01, 0.1, 'k'), (-0.01, 0.1, 'kp'), (-0.01, 0.1, 'kpb'), (-0.01, 0.1, 'kpbp'), (-0.01, 0.1, 'kpbpf'), (-0.01, 0.1, 'kpbpfq'), (0, -0.1, 'e'), (0, -0.1, 'eb'), (0, -0.1, 'ebp'), (0, -0.1, 'ebpb'), (0, -0.1, 'ebpbj'), (0, -0.01, 'e'), (0, -0.01, 'eb'), (0, -0.01, 'ebp'), (0, -0.01, 'ebpb'), (0, -0.01, 'ebpbp'), (0, -0.01, 'ebpbpb'), (0, -0.01, 'ebpbpb0'), (0, 0, 's'), (0, 0, 's0'), (0, 0, 's00'), (0, 0, 's000'), (0, 0.01, 's'), (0, 0.01, 's0'), (0, 0.01, 's00'), (0, 0.01, 's000'), (0, 0.01, 's0000'), (0, 0.01, 's00000'), (0, 0.01, 's00000p'), (0, 0.1, 's'), (0, 0.1, 's0'), (0, 0.1, 's00'), (0, 0.1, 's000'), (0, 0.1, 's0004'), (0.01, -0.1, 'e'), (0.01, -0.1, 'eb'), (0.01, -0.1, 'ebp'), (0.01, -0.1, 'ebpb'), (0.01, -0.1, 'ebpbj'), (0.01, -0.1, 'ebpbj9'), (0.01, -0.01, 'e'), (0.01, -0.01, 'eb'), (0.01, -0.01, 'ebp'), (0.01, -0.01, 'ebpb'), (0.01, -0.01, 'ebpbp'), (0.01, -0.01, 'ebpbpc'), (0.01, -0.01, 'ebpbpcb'), (0.01, 0, 's'), (0.01, 0, 's0'), (0.01, 0, 's00'), (0.01, 0, 's000'), (0.01, 0, 's0000'), (0.01, 0, 's00001'), (0.01, 0.01, 's'), (0.01, 0.01, 's0'), (0.01, 0.01, 's00'), (0.01, 0.01, 's000'), (0.01, 0.01, 's0000'), (0.01, 0.01, 's00001'), (0.01, 0.01, 's00001z'), (0.01, 0.1, 's'), (0.01, 0.1, 's0'), (0.01, 0.1, 's00'), (0.01, 0.1, 's000'), (0.01, 0.1, 's0004'), (0.01, 0.1, 's00043'), (0.1, -0.1, 'e'), (0.1, -0.1, 'eb'), (0.1, -0.1, 'ebp'), (0.1, -0.1, 'ebpb'), (0.1, -0.1, 'ebpbt'), (0.1, -0.01, 'e'), (0.1, -0.01, 'eb'), (0.1, -0.01, 'ebp'), (0.1, -0.01, 'ebpb'), (0.1, -0.01, 'ebpbx'), (0.1, -0.01, 'ebpbxf'), (0.1, -0.01, 'ebpbxf0'), (0.1, 0, 's'), (0.1, 0, 's0'), (0.1, 0, 's00'), (0.1, 0, 's000'), (0.1, 0, 's0008'), (0.1, 0.01, 's'), (0.1, 0.01, 's0'), (0.1, 0.01, 's00'), (0.1, 0.01, 's000'), (0.1, 0.01, 's0008'), (0.1, 0.01, 's00084'), (0.1, 0.01, 's00084p'), (0.1, 0.1, 's'), (0.1, 0.1, 's0'), (0.1, 0.1, 's00'), (0.1, 0.1, 's000'), (0.1, 0.1, 's000d'), (7.880886, 98.3640363, 'w'), (7.880886, 98.3640363, 'w1'), (7.880886, 98.3640363, 'w1m'), (7.880886, 98.3640363, 'w1mu'), (7.880886, 98.3640363, 'w1muy'), (7.880886, 98.3640363, 'w1muy6'), (7.880886, 98.3640363, 'w1muy6d'), (7.880886, 98.3640363, 'w1muy6dt'), (7.880886, 98.3640363, 'w1muy6dt2'), (7.880886, 98.3640363, 'w1muy6dt2p'), (7.880886, 98.3640363, 'w1muy6dt2pt'), (7.880886, 98.3640363, 'w1muy6dt2ptk'), (51.523242, -0.07914, 'g'), (51.523242, -0.07914, 'gc'), (51.523242, -0.07914, 'gcp'), (51.523242, -0.07914, 'gcpv'), (51.523242, -0.07914, 'gcpvn'), (51.523242, -0.07914, 'gcpvn5'), (51.523242, -0.07914, 'gcpvn5w'), (51.523242, -0.07914, 'gcpvn5w2'), (51.523242, -0.07914, 'gcpvn5w2e'), (51.523242, -0.07914, 'gcpvn5w2eu'), (51.523242, -0.07914, 'gcpvn5w2euk'), (51.523242, -0.07914, 'gcpvn5w2euky'), (53.923107, 27.606682, 'u'), (53.923107, 27.606682, 'u9'), (53.923107, 27.606682, 'u9e'), (53.923107, 27.606682, 'u9ed'), (53.923107, 27.606682, 'u9edu'), (53.923107, 27.606682, 'u9edu0'), (53.923107, 27.606682, 'u9edu0q'), (53.923107, 27.606682, 'u9edu0qs'), (53.923107, 27.606682, 'u9edu0qsf'), (53.923107, 27.606682, 'u9edu0qsf7'), (53.923107, 27.606682, 'u9edu0qsf7d'), (53.923107, 27.606682, 'u9edu0qsf7dn');
+
+
+select 'invalid values:'; -- must not crash
+select geohashEncode(181.0, 91.0);
+select geohashEncode(-181.0, -91.0);
+select count(geohashDecode('abcdefghijklmnopqrstuvwxyz'));
+
+select 'constant values:';
+select geohashEncode(-5.60302734375, 42.593994140625, 0);
+select round(geohashDecode('ezs42').1, 5), round(geohashDecode('ezs42').2, 5);
+
+select 'default precision:';
+select geohashEncode(-5.60302734375, 42.593994140625);
+
+select 'mixing const and non-const-columns:';
+select geohashEncode(materialize(-5.60302734375), materialize(42.593994140625), 0);
+select geohashEncode(materialize(-5.60302734375), materialize(42.593994140625), materialize(0)); -- { serverError 44 }
+
+
+select 'from table (with const precision):';
+
+-- here results are strings, so reference may contain values to match for equality.
+select 1 as p, geohashEncode(longitude, latitude, p) as actual, if(actual = encoded, 'Ok', concat('expected: ', encoded)) from geohash_test_data WHERE length(encoded) = p;
+select 2 as p, geohashEncode(longitude, latitude, p) as actual, if(actual = encoded, 'Ok', concat('expected: ', encoded)) from geohash_test_data WHERE length(encoded) = p;
+select 3 as p, geohashEncode(longitude, latitude, p) as actual, if(actual = encoded, 'Ok', concat('expected: ', encoded)) from geohash_test_data WHERE length(encoded) = p;
+select 4 as p, geohashEncode(longitude, latitude, p) as actual, if(actual = encoded, 'Ok', concat('expected: ', encoded)) from geohash_test_data WHERE length(encoded) = p;
+select 5 as p, geohashEncode(longitude, latitude, p) as actual, if(actual = encoded, 'Ok', concat('expected: ', encoded)) from geohash_test_data WHERE length(encoded) = p;
+select 6 as p, geohashEncode(longitude, latitude, p) as actual, if(actual = encoded, 'Ok', concat('expected: ', encoded)) from geohash_test_data WHERE length(encoded) = p;
+select 7 as p, geohashEncode(longitude, latitude, p) as actual, if(actual = encoded, 'Ok', concat('expected: ', encoded)) from geohash_test_data WHERE length(encoded) = p;
+select 8 as p, geohashEncode(longitude, latitude, p) as actual, if(actual = encoded, 'Ok', concat('expected: ', encoded)) from geohash_test_data WHERE length(encoded) = p;
+select 9 as p, geohashEncode(longitude, latitude, p) as actual, if(actual = encoded, 'Ok', concat('expected: ', encoded)) from geohash_test_data WHERE length(encoded) = p;
+select 10 as p, geohashEncode(longitude, latitude, p) as actual, if(actual = encoded, 'Ok', concat('expected: ', encoded)) from geohash_test_data WHERE length(encoded) = p;
+select 11 as p, geohashEncode(longitude, latitude, p) as actual, if(actual = encoded, 'Ok', concat('expected: ', encoded)) from geohash_test_data WHERE length(encoded) = p;
+select 12 as p, geohashEncode(longitude, latitude, p) as actual, if(actual = encoded, 'Ok', concat('expected: ', encoded)) from geohash_test_data WHERE length(encoded) = p;
+
+-- Here results are floats, and hence may not be compared for equality directly.
+-- We select all values that are off by some reasonable value:
+-- each byte of encoded string provides 5 bits of precison, (roughly 2.5 for lon and lat)
+-- each bit of precision divides value range by 2.
+-- hence max error is roughly value range 2.5 times divided by 2 for each precision bit.
+-- initial value range is [-90..90] for latitude and [-180..180] for longitude.
+select 'incorrectly decoded values:';
+select
+	geohashDecode(encoded) as actual,
+	'expected:', encoded, '=>', latitude, longitude,
+	'length:', 	length(encoded),
+	'max lat error:', 180 / power(2, 2.5 * length(encoded)) as latitude_max_error,
+	'max lon error:', 360 / power(2, 2.5 * length(encoded)) as longitude_max_error,
+	'err:', (actual.2 - latitude) as lat_error, (actual.1 - longitude) as lon_error,
+	'derr:', abs(lat_error) - latitude_max_error, abs(lon_error) - longitude_max_error
+from geohash_test_data
+where
+	abs(lat_error) > latitude_max_error
+	or
+	abs(lon_error) > longitude_max_error;
+
+drop table if exists geohash_test_data;

docs/en/query_language/functions/geo.md

@@ -98,5 +98,57 @@ SELECT pointInPolygon((3., 3.), [(6, 0), (8, 4), (5, 8), (0, 2)]) AS res
 └─────┘
 ```
 
+## geohashEncode
+
+Encodes latitude and longitude as a geohash-string, please see (http://geohash.org/, https://en.wikipedia.org/wiki/Geohash).
+```
+geohashEncode(longitude, latitude, [precision])
+```
+
+**Input values**
+
+- longitude - longitude part of the coordinate you want to encode. Floating in range`[-180°, 180°]`
+- latitude - latitude part of the coordinate you want to encode. Floating in range `[-90°, 90°]`
+- precision - Optional, length of the resulting encoded string, defaults to `12`. Integer in range `[1, 12]`. Any value less than `1` or greater than `12` is silently converted to `12`.
+
+**Returned values**
+
+- alphanumeric `String` of encoded coordinate (modified version of the base32-encoding alphabet is used).
+
+**Example**
+
+``` sql
+SELECT geohashEncode(-5.60302734375, 42.593994140625, 0) AS res
+```
+
+```
+┌─res──────────┐
+│ ezs42d000000 │
+└──────────────┘
+```
+
+## geohashDecode
+
+Decodes any geohash-encoded string into longitude and latitude.
+
+**Input values**
+
+- encoded string - geohash-encoded string.
+
+**Returned values**
+
+- (longitude, latitude) - 2-tuple of `Float64` values of longitude and latitude.
+
+**Example**
+
+``` sql
+SELECT geohashDecode('ezs42') AS res
+```
+
+```
+┌─res─────────────────────────────┐
+│ (-5.60302734375,42.60498046875) │
+└─────────────────────────────────┘
+```
 
 [Original article](https://clickhouse.yandex/docs/en/query_language/functions/geo/) <!--hide-->