mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-10 01:25:21 +00:00
DOCS-121: Introspection functions description (#7871)
* CLICKHOUSEDOCS-121: EN docs for the addressToLine function and the allow_introspection_functions setting. * CLICKHOUSEDOCS-121: Introspection functions description. * Update docs/en/query_language/functions/introspection.md Co-Authored-By: Ivan Blinkov <github@blinkov.ru> * CLICKHOUSEDOCS-121: Update by the comments.
This commit is contained in:
BayoNet
GitHub
commit
a95e585d6a
@ -1022,6 +1022,17 @@ Lower values mean higher priority. Threads with low `nice` priority values are e
|
||||
|
||||
Default value: 0.
|
||||
|
||||
## allow_introspection_functions {#settings-allow_introspection_functions}
|
||||
|
||||
Enables of disables [introspections functions](../../query_language/functions/introspection.md) for query profiling.
|
||||
|
||||
Possible values:
|
||||
|
||||
- 1 — Introspection functions enabled.
|
||||
- 0 — Introspection functions disabled.
|
||||
|
||||
Default value: 0.
|
||||
|
||||
## input_format_parallel_parsing
|
||||
|
||||
- Type: bool
|
||||
|
||||
298
docs/en/query_language/functions/introspection.md
Normal file
298
docs/en/query_language/functions/introspection.md
Normal file
@ -0,0 +1,298 @@
|
||||
# Introspection Functions
|
||||
|
||||
You can use functions described in this chapter to introspect [ELF](https://en.wikipedia.org/wiki/Executable_and_Linkable_Format) and [DWARF](https://en.wikipedia.org/wiki/DWARF) for query profiling.
|
||||
|
||||
!!! warning "Warning"
|
||||
These functions are slow and may impose security considerations.
|
||||
|
||||
For proper operation of introspection functions:
|
||||
|
||||
- Install the `clickhouse-common-static-dbg` package.
|
||||
- Set the [allow_introspection_functions](../../operations/settings/settings.md#settings-allow_introspection_functions) setting to 1.
|
||||
|
||||
For security reasons introspection functions are disabled by default.
|
||||
|
||||
ClickHouse saves profiler reports to the [trace_log](../../operations/system_tables.md#system_tables-trace_log) system table. Make sure the table and profiler are configured properly.
|
||||
|
||||
## addressToLine {#addresstoline}
|
||||
|
||||
Converts virtual memory address inside ClickHouse server process to the filename and the line number in ClickHouse source code.
|
||||
|
||||
If you use official ClickHouse packages, you need to install the `clickhouse-common-static-dbg` package.
|
||||
|
||||
**Syntax**
|
||||
|
||||
```sql
|
||||
addressToLine(address_of_binary_instruction)
|
||||
```
|
||||
|
||||
**Parameters**
|
||||
|
||||
- `address_of_binary_instruction` ([UInt64](../../data_types/int_uint.md)) — Address of instruction in a running process.
|
||||
|
||||
**Returned value**
|
||||
|
||||
- Source code filename and the line number in this file delimited by colon.
|
||||
|
||||
For example, `/build/obj-x86_64-linux-gnu/../dbms/src/Common/ThreadPool.cpp:199`, where `199` is a line number.
|
||||
|
||||
- Name of a binary, if the function couldn't find the debug information.
|
||||
- Empty string, if the address is not valid.
|
||||
|
||||
Type: [String](../../data_types/string.md).
|
||||
|
||||
**Example**
|
||||
|
||||
Enabling introspection functions:
|
||||
|
||||
```sql
|
||||
SET allow_introspection_functions=1
|
||||
```
|
||||
|
||||
Selecting the first string from the `trace_log` system table:
|
||||
|
||||
```sql
|
||||
SELECT * FROM system.trace_log LIMIT 1 \G
|
||||
```
|
||||
```text
|
||||
Row 1:
|
||||
──────
|
||||
event_date: 2019-11-19
|
||||
event_time: 2019-11-19 18:57:23
|
||||
revision: 54429
|
||||
timer_type: Real
|
||||
thread_number: 48
|
||||
query_id: 421b6855-1858-45a5-8f37-f383409d6d72
|
||||
trace: [140658411141617,94784174532828,94784076370703,94784076372094,94784076361020,94784175007680,140658411116251,140658403895439]
|
||||
```
|
||||
|
||||
The `trace` field contains the stack trace at the moment of sampling.
|
||||
|
||||
Getting the source code filename and the line number for a single address:
|
||||
|
||||
```sql
|
||||
SELECT addressToLine(94784076370703) \G
|
||||
```
|
||||
```text
|
||||
Row 1:
|
||||
──────
|
||||
addressToLine(94784076370703): /build/obj-x86_64-linux-gnu/../dbms/src/Common/ThreadPool.cpp:199
|
||||
```
|
||||
|
||||
Applying the function to the whole stack trace:
|
||||
|
||||
```sql
|
||||
SELECT
|
||||
arrayStringConcat(arrayMap(x -> addressToLine(x), trace), '\n') AS trace_source_code_lines
|
||||
FROM system.trace_log
|
||||
LIMIT 1
|
||||
\G
|
||||
```
|
||||
|
||||
The [arrayMap](higher_order_functions.md#higher_order_functions-array-map) function allows to process each individual element of the `trace` array by the `addressToLine` function. The result of this processing you see in the `trace_source_code_lines` column of output.
|
||||
|
||||
```text
|
||||
Row 1:
|
||||
──────
|
||||
trace_source_code_lines: /lib/x86_64-linux-gnu/libpthread-2.27.so
|
||||
/usr/lib/debug/usr/bin/clickhouse
|
||||
/build/obj-x86_64-linux-gnu/../dbms/src/Common/ThreadPool.cpp:199
|
||||
/build/obj-x86_64-linux-gnu/../dbms/src/Common/ThreadPool.h:155
|
||||
/usr/include/c++/9/bits/atomic_base.h:551
|
||||
/usr/lib/debug/usr/bin/clickhouse
|
||||
/lib/x86_64-linux-gnu/libpthread-2.27.so
|
||||
/build/glibc-OTsEL5/glibc-2.27/misc/../sysdeps/unix/sysv/linux/x86_64/clone.S:97
|
||||
```
|
||||
|
||||
## addressToSymbol {#addresstosymbol}
|
||||
|
||||
Converts virtual memory address inside ClickHouse server process to the symbol from ClickHouse object files.
|
||||
|
||||
|
||||
**Syntax**
|
||||
|
||||
```sql
|
||||
addressToSymbol(address_of_binary_instruction)
|
||||
```
|
||||
|
||||
**Parameters**
|
||||
|
||||
- `address_of_binary_instruction` ([UInt64](../../data_types/int_uint.md)) — Address of instruction in a running process.
|
||||
|
||||
**Returned value**
|
||||
|
||||
- Symbol from ClickHouse object files.
|
||||
- Empty string, if the address is not valid.
|
||||
|
||||
Type: [String](../../data_types/string.md).
|
||||
|
||||
**Example**
|
||||
|
||||
Enabling introspection functions:
|
||||
|
||||
```sql
|
||||
SET allow_introspection_functions=1
|
||||
```
|
||||
|
||||
Selecting the first string from the `trace_log` system table:
|
||||
|
||||
```sql
|
||||
SELECT * FROM system.trace_log LIMIT 1 \G
|
||||
```
|
||||
```text
|
||||
Row 1:
|
||||
──────
|
||||
event_date: 2019-11-20
|
||||
event_time: 2019-11-20 16:57:59
|
||||
revision: 54429
|
||||
timer_type: Real
|
||||
thread_number: 48
|
||||
query_id: 724028bf-f550-45aa-910d-2af6212b94ac
|
||||
trace: [94138803686098,94138815010911,94138815096522,94138815101224,94138815102091,94138814222988,94138806823642,94138814457211,94138806823642,94138814457211,94138806823642,94138806795179,94138806796144,94138753770094,94138753771646,94138753760572,94138852407232,140399185266395,140399178045583]
|
||||
```
|
||||
|
||||
The `trace` field contains the stack trace at the moment of sampling.
|
||||
|
||||
Getting a symbol for a single address:
|
||||
|
||||
```sql
|
||||
SELECT addressToSymbol(94138803686098) \G
|
||||
```
|
||||
```text
|
||||
Row 1:
|
||||
──────
|
||||
addressToSymbol(94138803686098): _ZNK2DB24IAggregateFunctionHelperINS_20AggregateFunctionSumImmNS_24AggregateFunctionSumDataImEEEEE19addBatchSinglePlaceEmPcPPKNS_7IColumnEPNS_5ArenaE
|
||||
```
|
||||
|
||||
Applying the function to the whole stack trace:
|
||||
|
||||
```sql
|
||||
SELECT
|
||||
arrayStringConcat(arrayMap(x -> addressToSymbol(x), trace), '\n') AS trace_symbols
|
||||
FROM system.trace_log
|
||||
LIMIT 1
|
||||
\G
|
||||
```
|
||||
|
||||
The [arrayMap](higher_order_functions.md#higher_order_functions-array-map) function allows to process each individual element of the `trace` array by the `addressToSymbols` function. The result of this processing you see in the `trace_symbols` column of output.
|
||||
|
||||
|
||||
```text
|
||||
Row 1:
|
||||
──────
|
||||
trace_symbols: _ZNK2DB24IAggregateFunctionHelperINS_20AggregateFunctionSumImmNS_24AggregateFunctionSumDataImEEEEE19addBatchSinglePlaceEmPcPPKNS_7IColumnEPNS_5ArenaE
|
||||
_ZNK2DB10Aggregator21executeWithoutKeyImplERPcmPNS0_28AggregateFunctionInstructionEPNS_5ArenaE
|
||||
_ZN2DB10Aggregator14executeOnBlockESt6vectorIN3COWINS_7IColumnEE13immutable_ptrIS3_EESaIS6_EEmRNS_22AggregatedDataVariantsERS1_IPKS3_SaISC_EERS1_ISE_SaISE_EERb
|
||||
_ZN2DB10Aggregator14executeOnBlockERKNS_5BlockERNS_22AggregatedDataVariantsERSt6vectorIPKNS_7IColumnESaIS9_EERS6_ISB_SaISB_EERb
|
||||
_ZN2DB10Aggregator7executeERKSt10shared_ptrINS_17IBlockInputStreamEERNS_22AggregatedDataVariantsE
|
||||
_ZN2DB27AggregatingBlockInputStream8readImplEv
|
||||
_ZN2DB17IBlockInputStream4readEv
|
||||
_ZN2DB26ExpressionBlockInputStream8readImplEv
|
||||
_ZN2DB17IBlockInputStream4readEv
|
||||
_ZN2DB26ExpressionBlockInputStream8readImplEv
|
||||
_ZN2DB17IBlockInputStream4readEv
|
||||
_ZN2DB28AsynchronousBlockInputStream9calculateEv
|
||||
_ZNSt17_Function_handlerIFvvEZN2DB28AsynchronousBlockInputStream4nextEvEUlvE_E9_M_invokeERKSt9_Any_data
|
||||
_ZN14ThreadPoolImplI20ThreadFromGlobalPoolE6workerESt14_List_iteratorIS0_E
|
||||
_ZZN20ThreadFromGlobalPoolC4IZN14ThreadPoolImplIS_E12scheduleImplIvEET_St8functionIFvvEEiSt8optionalImEEUlvE1_JEEEOS4_DpOT0_ENKUlvE_clEv
|
||||
_ZN14ThreadPoolImplISt6threadE6workerESt14_List_iteratorIS0_E
|
||||
execute_native_thread_routine
|
||||
start_thread
|
||||
clone
|
||||
```
|
||||
|
||||
## demangle {#demangle}
|
||||
|
||||
Converts a symbol that you can get using the [addressToSymbol](#addresstosymbol) function to the C++ function name.
|
||||
|
||||
|
||||
**Syntax**
|
||||
|
||||
```sql
|
||||
demangle(symbol)
|
||||
```
|
||||
|
||||
**Parameters**
|
||||
|
||||
- `symbol` ([String](../../data_types/string.md)) — Symbol from an object file.
|
||||
|
||||
**Returned value**
|
||||
|
||||
- Name of the C++ function.
|
||||
- Empty string if a symbol is not valid.
|
||||
|
||||
Type: [String](../../data_types/string.md).
|
||||
|
||||
**Example**
|
||||
|
||||
Enabling introspection functions:
|
||||
|
||||
```sql
|
||||
SET allow_introspection_functions=1
|
||||
```
|
||||
|
||||
Selecting the first string from the `trace_log` system table:
|
||||
|
||||
```sql
|
||||
SELECT * FROM system.trace_log LIMIT 1 \G
|
||||
```
|
||||
```text
|
||||
Row 1:
|
||||
──────
|
||||
event_date: 2019-11-20
|
||||
event_time: 2019-11-20 16:57:59
|
||||
revision: 54429
|
||||
timer_type: Real
|
||||
thread_number: 48
|
||||
query_id: 724028bf-f550-45aa-910d-2af6212b94ac
|
||||
trace: [94138803686098,94138815010911,94138815096522,94138815101224,94138815102091,94138814222988,94138806823642,94138814457211,94138806823642,94138814457211,94138806823642,94138806795179,94138806796144,94138753770094,94138753771646,94138753760572,94138852407232,140399185266395,140399178045583]
|
||||
```
|
||||
|
||||
The `trace` field contains the stack trace at the moment of sampling.
|
||||
|
||||
Getting a function name for a single address:
|
||||
|
||||
```sql
|
||||
SELECT demangle(addressToSymbol(94138803686098)) \G
|
||||
```
|
||||
```text
|
||||
Row 1:
|
||||
──────
|
||||
demangle(addressToSymbol(94138803686098)): DB::IAggregateFunctionHelper<DB::AggregateFunctionSum<unsigned long, unsigned long, DB::AggregateFunctionSumData<unsigned long> > >::addBatchSinglePlace(unsigned long, char*, DB::IColumn const**, DB::Arena*) const
|
||||
```
|
||||
|
||||
Applying the function to the whole stack trace:
|
||||
|
||||
```sql
|
||||
SELECT
|
||||
arrayStringConcat(arrayMap(x -> demangle(addressToSymbol(x)), trace), '\n') AS trace_functions
|
||||
FROM system.trace_log
|
||||
LIMIT 1
|
||||
\G
|
||||
```
|
||||
|
||||
The [arrayMap](higher_order_functions.md#higher_order_functions-array-map) function allows to process each individual element of the `trace` array by the `demangle` function. The result of this processing you see in the `trace_functions` column of output.
|
||||
|
||||
```text
|
||||
Row 1:
|
||||
──────
|
||||
trace_functions: DB::IAggregateFunctionHelper<DB::AggregateFunctionSum<unsigned long, unsigned long, DB::AggregateFunctionSumData<unsigned long> > >::addBatchSinglePlace(unsigned long, char*, DB::IColumn const**, DB::Arena*) const
|
||||
DB::Aggregator::executeWithoutKeyImpl(char*&, unsigned long, DB::Aggregator::AggregateFunctionInstruction*, DB::Arena*) const
|
||||
DB::Aggregator::executeOnBlock(std::vector<COW<DB::IColumn>::immutable_ptr<DB::IColumn>, std::allocator<COW<DB::IColumn>::immutable_ptr<DB::IColumn> > >, unsigned long, DB::AggregatedDataVariants&, std::vector<DB::IColumn const*, std::allocator<DB::IColumn const*> >&, std::vector<std::vector<DB::IColumn const*, std::allocator<DB::IColumn const*> >, std::allocator<std::vector<DB::IColumn const*, std::allocator<DB::IColumn const*> > > >&, bool&)
|
||||
DB::Aggregator::executeOnBlock(DB::Block const&, DB::AggregatedDataVariants&, std::vector<DB::IColumn const*, std::allocator<DB::IColumn const*> >&, std::vector<std::vector<DB::IColumn const*, std::allocator<DB::IColumn const*> >, std::allocator<std::vector<DB::IColumn const*, std::allocator<DB::IColumn const*> > > >&, bool&)
|
||||
DB::Aggregator::execute(std::shared_ptr<DB::IBlockInputStream> const&, DB::AggregatedDataVariants&)
|
||||
DB::AggregatingBlockInputStream::readImpl()
|
||||
DB::IBlockInputStream::read()
|
||||
DB::ExpressionBlockInputStream::readImpl()
|
||||
DB::IBlockInputStream::read()
|
||||
DB::ExpressionBlockInputStream::readImpl()
|
||||
DB::IBlockInputStream::read()
|
||||
DB::AsynchronousBlockInputStream::calculate()
|
||||
std::_Function_handler<void (), DB::AsynchronousBlockInputStream::next()::{lambda()#1}>::_M_invoke(std::_Any_data const&)
|
||||
ThreadPoolImpl<ThreadFromGlobalPool>::worker(std::_List_iterator<ThreadFromGlobalPool>)
|
||||
ThreadFromGlobalPool::ThreadFromGlobalPool<ThreadPoolImpl<ThreadFromGlobalPool>::scheduleImpl<void>(std::function<void ()>, int, std::optional<unsigned long>)::{lambda()#3}>(ThreadPoolImpl<ThreadFromGlobalPool>::scheduleImpl<void>(std::function<void ()>, int, std::optional<unsigned long>)::{lambda()#3}&&)::{lambda()#1}::operator()() const
|
||||
ThreadPoolImpl<std::thread>::worker(std::_List_iterator<std::thread>)
|
||||
execute_native_thread_routine
|
||||
start_thread
|
||||
clone
|
||||
```
|
||||
@ -119,6 +119,7 @@ nav:
|
||||
- 'Working with geographical coordinates': 'query_language/functions/geo.md'
|
||||
- 'Working with Nullable arguments': 'query_language/functions/functions_for_nulls.md'
|
||||
- 'Machine Learning Functions': 'query_language/functions/machine_learning_functions.md'
|
||||
- 'Introspection': 'query_language/functions/introspection.md'
|
||||
- 'Other': 'query_language/functions/other_functions.md'
|
||||
- 'Aggregate Functions':
|
||||
- 'Introduction': 'query_language/agg_functions/index.md'
|
||||
|
||||
Loading…
Reference in New Issue
Block a user