C Native API
C Native API
1. Overview
The C Native API (SessionC) is a C language wrapper for the C++ Session SDK. It is used in the same way as the C++ driver. You only need to include the additional header file SessionC.h. Compilation, linking, and runtime deployment share the same iotdb_session shared library as the C++ driver.
Thrift and Boost are already packaged into iotdb_session. Applications do not need to install Thrift or Boost headers/libraries separately.
Note: This feature is supported since V2.0.10.
2. Installation
2.1 Option 1: Use the precompiled SDK package (recommended)
CI publishes zip packages by platform/toolchain. The file name is in the form iotdb-session-cpp-<version>-<classifier>.zip. After extraction, the directory structure is as follows:
iotdb-session-cpp-<version>-<classifier>/
├── include/
│ ├── SessionC.h # C Native API header file
│ ├── Session.h # C++ API header file
│ └── ...
├── lib/
│ ├── libiotdb_session.so # Linux
│ ├── libiotdb_session.dylib # macOS
│ └── iotdb_session.dll + .lib # Windows
├── cmake/iotdb-session-config.cmake
├── pkgconfig/iotdb-session.pc
└── examples/ # Includes tree_example.cSelect the classifier according to the target environment:
| Target environment | classifier suffix |
|---|---|
| Linux x86_64, glibc >= 2.28 | linux-x86_64-glibc2.28 |
| Linux aarch64, glibc >= 2.28 | linux-aarch64-glibc2.28 |
| macOS x86_64 | macos-x86_64 |
| macOS arm64 | macos-aarch64 |
| Windows + Visual Studio 2017 | windows-x86_64-msvc14.1 |
| Windows + Visual Studio 2019 | windows-x86_64-msvc14.2 |
| Windows + Visual Studio 2022 | windows-x86_64-msvc14.3 |
| Windows + Visual Studio 2026 | windows-x86_64-msvc14.4 |
Note: Do not use a higher-version client to connect to a lower-version server.
2.1.1 C program compilation example
Linux / macOS:
gcc -std=c11 tree_example.c \
-I"$IOTDB_SESSION_HOME/include" \
-L"$IOTDB_SESSION_HOME/lib" \
-liotdb_session -pthread \
-Wl,-rpath,"$IOTDB_SESSION_HOME/lib" \
-o tree_exampleWindows + MSVC:
Compile in the x64 Native Tools Command Prompt (or run vcvars64.bat first to initialize the environment):
set IOTDB_SESSION_HOME=C:\path\to\iotdb-session-cpp-<version>-<classifier>
cd /d %IOTDB_SESSION_HOME%\examples
cl /TC /std:c11 tree_example.c /I "%IOTDB_SESSION_HOME%\include" ^
/link /LIBPATH:"%IOTDB_SESSION_HOME%\lib" iotdb_session.lib
copy /Y "%IOTDB_SESSION_HOME%\lib\iotdb_session.dll" .At runtime, place libiotdb_session.so / .dylib / .dll in the same directory as the executable, or configure the corresponding dynamic library search path for your platform.
2.1.2 Compile examples in the SDK package
Run the following commands in the root directory of the extracted SDK package. The examples/ directory must be at the same level as include/ and lib/.
cd iotdb-session-cpp-<version>-<classifier>
cmake -S examples -B examples-build -DCMAKE_BUILD_TYPE=Release
cmake --build examples-buildWindows + Visual Studio:
cd iotdb-session-cpp-<version>-<classifier>
cmake -S examples -B examples-build -G "Visual Studio 17 2022" -A x64
cmake --build examples-build --config ReleaseIf the library is installed in another path, such as the source CMake installation directory iotdb-client/client-cpp/target/install, explicitly specify IOTDB_SDK_ROOT. This directory must contain include/ and lib/.
cmake -S iotdb-client/client-cpp/examples -B examples-build -DCMAKE_BUILD_TYPE=Release \
-DIOTDB_SDK_ROOT=iotdb-client/client-cpp/target/install
cmake --build examples-buildWindows example:
cmake -S iotdb-client\client-cpp\examples -B examples-build -G "Visual Studio 17 2022" -A x64 ^
-DIOTDB_SDK_ROOT=D:\iotdb\iotdb-client\client-cpp\target\install
cmake --build examples-build --config Release --target tree_example2.2 Option 2: Build from source
2.2.1 Install build dependencies (required only for source builds)
- macOS
brew install bison boost openssl- Ubuntu 16.04+ or other Debian distributions
sudo apt-get update
sudo apt-get install gcc g++ bison flex libboost-all-dev libssl-dev cmake- CentOS 7.7+/Fedora/Rocky Linux or other Red Hat distributions
sudo yum update
sudo yum install gcc gcc-c++ boost-devel bison flex openssl-devel cmake- Windows
Install MS Visual Studio (2019+ recommended), and select the C/C++ IDE and compiler components with CMake support.
Install CMake.
Install Win_Flex_Bison, rename the executables to
flex.exeandbison.exe, and add them to PATH.Install Boost (optional, CMake can also fetch it automatically) and OpenSSL.
The CMake build compiles Thrift 0.23 from source. SSL is enabled by default. If system OpenSSL cannot be found, the build falls back to building OpenSSL from source.
2.2.2 Build
Clone the source code from git:
git clone https://github.com/apache/iotdb.git
cd iotdbTo use a specific release version, switch to the corresponding branch, such as 2.0.6:
git checkout rc/2.0.6Run the Maven build in the IoTDB root directory (recommended):
# Linux / macOS: build and package the SDK
./mvnw -P with-cpp -pl iotdb-client/client-cpp -am -DskipTests package
# Windows (Visual Studio 2022 example)
.\mvnw.cmd -P with-cpp -pl iotdb-client/client-cpp -am -DskipTests packageIf Boost is not added to PATH on Windows, append a parameter such as:
-Dboost.include.dir="C:\boost_1_88_0"You can also use CMake directly:
cmake -S iotdb-client/client-cpp -B build
cmake --build build --target installLinux release packages are built in the manylinux_2_28 container. The target machine requires glibc 2.28 or later. The current build no longer uses old parameters such as -Diotdb-tools-thrift.version=0.14.1.1-gcc4-SNAPSHOT.
Full verification with integration tests:
./mvnw clean verify -P with-cpp -pl iotdb-client/client-cpp -am2.3 Build artifacts
After a successful build, C API related files are located as follows:
C API header file (source):
iotdb-client/client-cpp/src/include/SessionC.hC API header file (installation/SDK package):
include/SessionC.hLibrary files:
Source build:
iotdb-client/client-cpp/target/install/lib/Maven package:
iotdb-client/client-cpp/target/iotdb-session-cpp-<version>-<classifier>.zipLinux:
lib/libiotdb_session.soWindows:
lib/iotdb_session.dll/lib/iotdb_session.lib
Example source code:
Tree model:
iotdb-client/client-cpp/examples/tree_example.cTable model:
iotdb-client/client-cpp/examples/table_example.c
Integration tests:
Tree model:
iotdb-client/client-cpp/test/cpp/sessionCIT.cppTable model:
iotdb-client/client-cpp/test/cpp/sessionCRelationalIT.cpp
3. Basic API description
Description: The C driver is used in the same way as the C++ driver. You only need to include the additional header file SessionC.h. Compilation, runtime behavior, and system dependencies are shared with the C++ driver.
3.1 Common conventions
3.1.1 Status codes and error messages
TsStatus:TS_OK (0)indicates success. Any non-zero value indicates failure.Predefined error codes:
TS_ERR_CONNECTION (-1)TS_ERR_EXECUTION (-2)TS_ERR_INVALID_PARAM (-3)TS_ERR_NULL_PTR (-4)TS_ERR_UNKNOWN (-99)
The implementation may also return other negative values, which must be interpreted together with
ts_get_last_error().The Session C++ API reports many errors through exceptions and does not return a unified status code. The C API uniformly returns the integer type
TsStatus, and fine-grained error information can be obtained throughts_get_last_error().
const char* ts_get_last_error(void);Returns the error message of the last failed C API call in the current thread. The returned pointer is valid until the next C API call in the same thread.
3.1.2 Memory and handle rules
All
char* buf + int bufLenoutput parameters must be allocated by the caller.CSession*,CTablet*,CSessionDataSet*, andCRowRecord*are opaque pointers. After successful creation, the caller must release them according to the conventions of each API.
3.2 Enumerations and constants
- TSDataType_C (data type)
| Enumeration value | Meaning |
|---|---|
TS_TYPE_BOOLEAN | Boolean |
TS_TYPE_INT32 | 32-bit integer |
TS_TYPE_INT64 | 64-bit integer |
TS_TYPE_FLOAT | Single-precision floating point |
TS_TYPE_DOUBLE | Double-precision floating point |
TS_TYPE_TEXT | Text |
TS_TYPE_TIMESTAMP | Timestamp |
TS_TYPE_DATE | Date |
TS_TYPE_BLOB | Binary large object |
TS_TYPE_STRING | String |
TS_TYPE_INVALID | Invalid parameter/error path (not a server-side type) |
- TSEncoding_C (encoding)
TS_ENCODING_PLAIN, TS_ENCODING_DICTIONARY, TS_ENCODING_RLE, TS_ENCODING_DIFF, TS_ENCODING_TS_2DIFF, TS_ENCODING_BITMAP, TS_ENCODING_GORILLA_V1, TS_ENCODING_REGULAR, TS_ENCODING_GORILLA, TS_ENCODING_ZIGZAG, TS_ENCODING_FREQ
- TSCompressionType_C (compression)
TS_COMPRESSION_UNCOMPRESSED, TS_COMPRESSION_SNAPPY, TS_COMPRESSION_GZIP, TS_COMPRESSION_LZO, TS_COMPRESSION_SDT, TS_COMPRESSION_PAA, TS_COMPRESSION_PLA, TS_COMPRESSION_LZ4, TS_COMPRESSION_ZSTD, TS_COMPRESSION_LZMA2
3.3 Handles, status codes, and constants
| Name | C definition | Meaning | Lifecycle responsibility |
|---|---|---|---|
CSession* | typedef struct CSession_ CSession; | Tree model session | After ts_session_new / ts_session_new_with_zone / ts_session_new_multi_node succeeds, the caller calls ts_session_close if it has been opened, and then ts_session_destroy |
CTablet* | typedef struct CTablet_ CTablet; (opaque) | Tablet batch writing, shared by tree and table models | After ts_tablet_new / ts_tablet_new_with_category succeeds, the caller calls ts_tablet_destroy |
CSessionDataSet* | typedef struct CSessionDataSet_ CSessionDataSet; (opaque) | Query result set, shared by tree and table models | After a query API successfully returns *dataSet, the caller calls ts_dataset_destroy |
CRowRecord* | typedef struct CRowRecord_ CRowRecord; (opaque) | Current row | When ts_dataset_next returns a non-null value, the caller calls ts_row_record_destroy |
TsStatus | typedef int64_t TsStatus; | API execution result code | TS_OK is 0. Any non-zero value indicates failure |
ts_get_last_error | const char* ts_get_last_error(void); | Error message of the last failed C API call in the current thread | The returned pointer is valid until the next C API call in the same thread |
3.4 Common Tablet APIs
3.4.1 Creation and destruction
| API signature | Function | Input parameters | Return value | Success condition | Failure condition | Resource responsibility |
|---|---|---|---|---|---|---|
CTablet* ts_tablet_new(const char* deviceId, int columnCount, const char* const* columnNames, const TSDataType_C* dataTypes, int maxRowNumber); | Create a Tablet handle | deviceId: device or table name; columnNames / dataTypes: arrays of column names and types; maxRowNumber: maximum number of rows | CTablet* | Returns a non-null handle | Returns a null handle | Caller calls ts_tablet_destroy |
void ts_tablet_destroy(CTablet* tablet); | Destroy a Tablet handle | tablet: handle to release | None | The handle must not be used after the call | - | Releases tablet |
3.4.2 Data filling and state control
| API signature | Function | Return value | Success condition | Remarks |
|---|---|---|---|---|
int ts_tablet_get_row_count(CTablet* tablet); | Query the current valid row count of the Tablet | int | Row count >= 0 | Read-only query |
TsStatus ts_tablet_set_row_count(CTablet* tablet, int rowCount); | Set the valid row count of the Tablet | TsStatus | TS_OK | The valid row count must be set before writing |
TsStatus ts_tablet_add_timestamp(CTablet* tablet, int rowIndex, int64_t timestamp); | Write a timestamp for the specified row | TsStatus | TS_OK | |
TsStatus ts_tablet_add_value_bool(CTablet* tablet, int colIndex, int rowIndex, bool value); | Write a Boolean value | TsStatus | TS_OK | |
TsStatus ts_tablet_add_value_int32(CTablet* tablet, int colIndex, int rowIndex, int32_t value); | Write an int32 value | TsStatus | TS_OK | |
TsStatus ts_tablet_add_value_int64(CTablet* tablet, int colIndex, int rowIndex, int64_t value); | Write an int64 value | TsStatus | TS_OK | |
TsStatus ts_tablet_add_value_float(CTablet* tablet, int colIndex, int rowIndex, float value); | Write a float value | TsStatus | TS_OK | |
TsStatus ts_tablet_add_value_double(CTablet* tablet, int colIndex, int rowIndex, double value); | Write a double value | TsStatus | TS_OK | |
TsStatus ts_tablet_add_value_string(CTablet* tablet, int colIndex, int rowIndex, const char* value); | Write a string | TsStatus | TS_OK | String memory is managed by the caller |
void ts_tablet_reset(CTablet* tablet); | Reset the internal state of the Tablet for reuse | void | - | Does not release the object. Only clears the state |
Description: The current SessionC implementation does not provide
ts_tablet_add_value_object. Use the C++ Session API to write OBJECT values.
3.5 Common DataSet APIs
3.5.1 Iteration control and metadata
| API signature | Function | Return value | Remarks |
|---|---|---|---|
void ts_dataset_set_fetch_size(CSessionDataSet* dataSet, int fetchSize); | Set the fetch batch size of the result set | None | |
bool ts_dataset_has_next(CSessionDataSet* dataSet); | Determine whether there may be another row | bool | On failure, check ts_get_last_error() |
CRowRecord* ts_dataset_next(CSessionDataSet* dataSet); | Get the next row record handle | Row handle pointer | Non-NULL indicates a valid row. NULL indicates end or failure |
int ts_dataset_get_column_count(CSessionDataSet* dataSet); | Get the number of columns in the result set | int | |
const char* ts_dataset_get_column_name(CSessionDataSet* dataSet, int index); | Get a column name by index | String pointer | No buf/bufLen output |
const char* ts_dataset_get_column_type(CSessionDataSet* dataSet, int index); | Get a column type name by index | Type name string pointer | No buf/bufLen output |
void ts_dataset_destroy(CSessionDataSet* dataSet); | Release a query result set handle | None | After each non-null CRowRecord* returned by ts_dataset_next, call ts_row_record_destroy in time |
3.5.2 Value access
| API signature | Function | Return value | Remarks |
|---|---|---|---|
void ts_row_record_destroy(CRowRecord* record); | Release a row record handle | None | |
int64_t ts_row_record_get_timestamp(CRowRecord* record); | Read the timestamp of the current row | int64_t | The timestamp is not read from DataSet |
int ts_row_record_get_field_count(CRowRecord* record); | Read the number of fields in the current row | int | |
bool ts_row_record_is_null(CRowRecord* record, int index); | Determine whether the specified column is null | bool | |
bool ts_row_record_get_bool(CRowRecord* record, int index); | Read a Boolean value by column index | bool | |
int32_t ts_row_record_get_int32(CRowRecord* record, int index); | Read an int32 value by column index | int32_t | |
int64_t ts_row_record_get_int64(CRowRecord* record, int index); | Read an int64 value by column index | int64_t | |
float ts_row_record_get_float(CRowRecord* record, int index); | Read a float value by column index | float | |
double ts_row_record_get_double(CRowRecord* record, int index); | Read a double value by column index | double | |
const char* ts_row_record_get_string(CRowRecord* record, int index); | Read the byte view of a text/binary column | const char. | May contain .. Not a buf . bufLen pattern |
int32_t ts_row_record_get_date_int32(CRowRecord* record, int index); | Read a DATE column and return an integer in YYYYMMDD format | int32_t | Returns 0 if the field is null, out of bounds, or not DATE |
size_t ts_row_record_get_string_byte_length(CRowRecord* record, int index); | Read the byte length of a string/binary field | size_t | TEXT/BLOB/STRING, etc. Do not use strlen |
TSDataType_C ts_row_record_get_data_type(CRowRecord* record, int index); | Read the data type enumeration by column index | Enumeration | Returns TS_TYPE_INVALID for invalid parameters or out-of-bounds indexes |
3.6 Tree model CSession API matrix
3.6.1 Lifecycle and session properties
| API signature | Function | Return value | Success condition | Resource responsibility |
|---|---|---|---|---|
CSession* ts_session_new(const char* host, int rpcPort, const char* username, const char* password); | Create a tree model session (single host) | CSession* | Returns a non-null handle | If opened, call ts_session_close first, and then ts_session_destroy |
CSession* ts_session_new_with_zone(const char* host, int rpcPort, const char* username, const char* password, const char* zoneId, int fetchSize); | Create a session and specify the time zone and fetch size | CSession* | Returns a non-null handle | Same as above |
CSession* ts_session_new_multi_node(const char* const* nodeUrls, int urlCount, const char* username, const char* password); | Create a tree model session (multi-node URL) | CSession* | Returns a non-null handle | Same as above |
void ts_session_destroy(CSession* session); | Destroy a tree model session handle | None | - | Releases session |
TsStatus ts_session_open(CSession* session); | Open a tree model RPC connection | TsStatus | TS_OK | On failure, read ts_get_last_error() |
TsStatus ts_session_open_with_compression(CSession* session, bool enableRPCCompression); | Open a connection and set whether to enable RPC compression | TsStatus | TS_OK | Same as above |
TsStatus ts_session_close(CSession* session); | Close a tree model connection | TsStatus | TS_OK | ts_session_destroy is still required |
TsStatus ts_session_set_timezone(CSession* session, const char* zoneId); | Set the session time zone | TsStatus | TS_OK | |
TsStatus ts_session_get_timezone(CSession* session, char* buf, int bufLen); | Get the current session time zone string into a buffer | TsStatus | TS_OK and buf is valid | The caller allocates the buffer |
3.6.2 Schema management
| API signature | Function | Return value | Remarks |
|---|---|---|---|
TsStatus ts_session_create_database(CSession* session, const char* database); | Create a database | TsStatus | |
TsStatus ts_session_delete_database(CSession* session, const char* database); | Delete a database | TsStatus | |
TsStatus ts_session_delete_databases(CSession* session, const char* const* databases, int count); | Delete databases in batches | TsStatus | |
TsStatus ts_session_create_timeseries(CSession* session, const char* path, TSDataType_C dataType, TSEncoding_C encoding, TSCompressionType_C compressor); | Create a single timeseries | TsStatus | |
TsStatus ts_session_create_timeseries_ex(CSession* session, const char* path, TSDataType_C dataType, TSEncoding_C encoding, TSCompressionType_C compressor, int propsCount, const char* const* propKeys, const char* const* propValues, int tagsCount, const char* const* tagKeys, const char* const* tagValues, int attrsCount, const char* const* attrKeys, const char* const* attrValues, const char* measurementAlias); | Create a timeseries with extensions such as properties, tags, attributes, and alias | TsStatus | propsCount/tagsCount/attrsCount must match their corresponding key/value arrays. measurementAlias can be NULL |
TsStatus ts_session_create_multi_timeseries(CSession* session, int count, const char* const* paths, const TSDataType_C* dataTypes, const TSEncoding_C* encodings, const TSCompressionType_C* compressors); | Create timeseries in batches | TsStatus | |
TsStatus ts_session_create_aligned_timeseries(CSession* session, const char* deviceId, int count, const char* const* measurements, const TSDataType_C* dataTypes, const TSEncoding_C* encodings, const TSCompressionType_C* compressors); | Create aligned timeseries under the specified device | TsStatus | |
TsStatus ts_session_check_timeseries_exists(CSession* session, const char* path, bool* exists); | Check whether the timeseries for the path exists | TsStatus | Existence is output through bool* |
TsStatus ts_session_delete_timeseries(CSession* session, const char* path); | Delete a single timeseries | TsStatus | |
TsStatus ts_session_delete_timeseries_batch(CSession* session, const char* const* paths, int count); | Delete timeseries in batches | TsStatus |
3.6.3 Writing
| API signature | Function | Return value | Remarks |
|---|---|---|---|
TsStatus ts_session_insert_record_str(CSession* session, const char* deviceId, int64_t time, int count, const char* const* measurements, const char* const* values); | Insert one record for one device (string values) | TsStatus | No new handle |
TsStatus ts_session_insert_record(CSession* session, const char* deviceId, int64_t time, int count, const char* const* measurements, const TSDataType_C* types, const void* const* values); | Insert one record for one device (strongly typed values) | TsStatus | values[i] points to the value of the type corresponding to types[i] |
TsStatus ts_session_insert_aligned_record_str(CSession* session, const char* deviceId, int64_t time, int count, const char* const* measurements, const char* const* values); | Insert one record for an aligned device (string values) | TsStatus | |
TsStatus ts_session_insert_aligned_record(CSession* session, const char* deviceId, int64_t time, int count, const char* const* measurements, const TSDataType_C* types, const void* const* values); | Insert one record for an aligned device (strongly typed values) | TsStatus | |
TsStatus ts_session_insert_records_str(CSession* session, int deviceCount, const char* const* deviceIds, const int64_t* times, const int* measurementCounts, const char* const* const* measurementsList, const char* const* const* valuesList); | Batch insert for multiple devices (string values) | TsStatus | The lengths of measurementsList[i] / valuesList[i] are determined by measurementCounts[i] |
TsStatus ts_session_insert_aligned_records_str(CSession* session, int deviceCount, const char* const* deviceIds, const int64_t* times, const int* measurementCounts, const char* const* const* measurementsList, const char* const* const* valuesList); | Batch insert for multiple aligned devices (string values) | TsStatus | Same as above |
TsStatus ts_session_insert_records(CSession* session, int deviceCount, const char* const* deviceIds, const int64_t* times, const int* measurementCounts, const char* const* const* measurementsList, const TSDataType_C* const* typesList, const void* const* const* valuesList); | Batch insert for multiple devices (strongly typed values) | TsStatus | |
TsStatus ts_session_insert_aligned_records(CSession* session, int deviceCount, const char* const* deviceIds, const int64_t* times, const int* measurementCounts, const char* const* const* measurementsList, const TSDataType_C* const* typesList, const void* const* const* valuesList); | Batch insert for multiple aligned devices (strongly typed values) | TsStatus | |
TsStatus ts_session_insert_records_of_one_device(CSession* session, const char* deviceId, int rowCount, const int64_t* times, const int* measurementCounts, const char* const* const* measurementsList, const TSDataType_C* const* typesList, const void* const* const* valuesList, bool sorted); | Batch insert multiple rows for one device | TsStatus | sorted indicates whether timestamps are already sorted |
TsStatus ts_session_insert_aligned_records_of_one_device(CSession* session, const char* deviceId, int rowCount, const int64_t* times, const int* measurementCounts, const char* const* const* measurementsList, const TSDataType_C* const* typesList, const void* const* const* valuesList, bool sorted); | Batch insert multiple aligned rows for one device | TsStatus | Same as above |
TsStatus ts_session_insert_tablet(CSession* session, CTablet* tablet, bool sorted); | Batch write by Tablet in the tree model | TsStatus | Ownership of tablet is not transferred |
TsStatus ts_session_insert_aligned_tablet(CSession* session, CTablet* tablet, bool sorted); | Batch write by Tablet in the aligned model | TsStatus | Ownership of tablet is not transferred |
TsStatus ts_session_insert_tablets(CSession* session, int tabletCount, const char* const* deviceIds, CTablet** tablets, bool sorted); | Batch write multiple Tablets | TsStatus | Ownership of tablets is not transferred |
TsStatus ts_session_insert_aligned_tablets(CSession* session, int tabletCount, const char* const* deviceIds, CTablet** tablets, bool sorted); | Batch write multiple aligned Tablets | TsStatus | Same as above |
3.6.4 Querying
| API signature | Function | Return value | Resource responsibility |
|---|---|---|---|
TsStatus ts_session_execute_query(CSession* session, const char* sql, CSessionDataSet** dataSet); | Execute query SQL and return a result set | TsStatus | Caller calls ts_dataset_destroy for *dataSet |
TsStatus ts_session_execute_query_with_timeout(CSession* session, const char* sql, int64_t timeoutInMs, CSessionDataSet** dataSet); | Execute a query with timeout | TsStatus | Same as above |
TsStatus ts_session_execute_non_query(CSession* session, const char* sql); | Execute non-query SQL | TsStatus | No new handle |
TsStatus ts_session_execute_raw_data_query(CSession* session, int pathCount, const char* const* paths, int64_t startTime, int64_t endTime, CSessionDataSet** dataSet); | Query raw data by paths and time range | TsStatus | Caller destroys *dataSet |
TsStatus ts_session_execute_last_data_query(CSession* session, int pathCount, const char* const* paths, CSessionDataSet** dataSet); | Query last point data for specified paths | TsStatus | Caller destroys *dataSet |
TsStatus ts_session_execute_last_data_query_with_time(CSession* session, int pathCount, const char* const* paths, int64_t lastTime, CSessionDataSet** dataSet); | Query last point data with lastTime | TsStatus | Caller destroys *dataSet |
3.6.5 Data deletion
| API signature | Function | Return value |
|---|---|---|
TsStatus ts_session_delete_data(CSession* session, const char* path, int64_t endTime); | Delete data by path | TsStatus |
TsStatus ts_session_delete_data_batch(CSession* session, int pathCount, const char* const* paths, int64_t endTime); | Delete data by multiple paths in batches | TsStatus |
TsStatus ts_session_delete_data_range(CSession* session, int pathCount, const char* const* paths, int64_t startTime, int64_t endTime); | Delete data by time range | TsStatus |
4. Sample code
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "SessionC.h"
#define HOST "127.0.0.1"
#define PORT 6667
#define USER "root"
#define PASS "root"
#define TS_PATH "root.cdemo.d0.s0"
#define DEVICE "root.cdemo.d0"
static void fail(const char* ctx, CSession* s) {
fprintf(stderr, "[tree_example] %s failed: %s.", ctx, ts_get_last_error());
if (s) {
ts_session_close(s);
ts_session_destroy(s);
}
exit(1);
}
int main(void) {
const char* path = TS_PATH;
CSession* session = ts_session_new(HOST, PORT, USER, PASS);
if (!session) {
fprintf(stderr, "[tree_example] ts_session_new returned NULL: %s.", ts_get_last_error());
return 1;
}
if (ts_session_open(session) != TS_OK) {
fail("ts_session_open", session);
}
bool exists = false;
if (ts_session_check_timeseries_exists(session, path, &exists) != TS_OK) {
fail("ts_session_check_timeseries_exists", session);
}
if (exists) {
if (ts_session_delete_timeseries(session, path) != TS_OK) {
fail("ts_session_delete_timeseries (cleanup old)", session);
}
}
if (ts_session_create_timeseries(session, path, TS_TYPE_INT64, TS_ENCODING_RLE,
TS_COMPRESSION_SNAPPY) != TS_OK) {
fail("ts_session_create_timeseries", session);
}
const char* measurements[] = {"s0"};
const char* values[] = {"100"};
if (ts_session_insert_record_str(session, DEVICE, 1LL, 1, measurements, values) != TS_OK) {
fail("ts_session_insert_record_str", session);
}
CSessionDataSet* dataSet = NULL;
if (ts_session_execute_query(session, "select s0 from root.cdemo.d0", &dataSet) != TS_OK) {
fail("ts_session_execute_query", session);
}
if (!dataSet) {
fprintf(stderr, "[tree_example] dataSet is NULL.");
ts_session_close(session);
ts_session_destroy(session);
return 1;
}
ts_dataset_set_fetch_size(dataSet, 1024);
int rows = 0;
while (ts_dataset_has_next(dataSet)) {
CRowRecord* record = ts_dataset_next(dataSet);
if (!record) {
break;
}
int64_t v = ts_row_record_get_int64(record, 0);
printf("[tree_example] row %d: s0 = %lld.", rows, (long long)v);
ts_row_record_destroy(record);
rows++;
}
ts_dataset_destroy(dataSet);
printf("[tree_example] done, read %d row(s)..", rows);
if (ts_session_delete_timeseries(session, path) != TS_OK) {
fail("ts_session_delete_timeseries", session);
}
ts_session_close(session);
ts_session_destroy(session);
return 0;
}