ClickHouse/docs/en/operations/system-tables/symbols.md

slug
/en/operations/system-tables/symbols

symbols

Contains information for introspection of clickhouse binary. It requires the introspection privilege to access. This table is only usable for C++ experts and ClickHouse engineers.

Columns:

• symbol (String) — Symbol name in the binary. It is mangled. You can apply demangle(symbol) to obtain a readable name.
• address_begin (UInt64) — Start address of the symbol in the binary.
• address_end (UInt64) — End address of the symbol in the binary.
• name (String) — Alias for event.

Example

SELECT address_begin, address_end - address_begin AS size, demangle(symbol) FROM system.symbols ORDER BY size DESC LIMIT 10

┌─address_begin─┬─────size─┬─demangle(symbol)──────────────────────────────────────────────────────────────────┐
│      25000976 │ 29466000 │ icudt70_dat                                                                       │
│     400605288 │  2097272 │ arena_emap_global                                                                 │
│      18760592 │  1048576 │ CLD2::kQuadChrome1015_2                                                           │
│       9807152 │   884808 │ TopLevelDomainLookupHash::isValid(char const*, unsigned long)::wordlist           │
│      57442432 │   850608 │ llvm::X86Insts                                                                    │
│      55682944 │   681360 │ (anonymous namespace)::X86DAGToDAGISel::SelectCode(llvm::SDNode*)::MatcherTable   │
│      55130368 │   502840 │ (anonymous namespace)::X86InstructionSelector::getMatchTable() const::MatchTable0 │
│     402930616 │   404032 │ qpl::ml::dispatcher::hw_dispatcher::get_instance()::instance                      │
│     274131872 │   356795 │ DB::SettingsTraits::Accessor::instance()::$_0::operator()() const                 │
│      58293040 │   249424 │ llvm::X86InstrNameData                                                            │
└───────────────┴──────────┴───────────────────────────────────────────────────────────────────────────────────┘