BT.stats

Function

returns the runtime resource statistics of the current BT process, which is used to locate I/O running boundaries, background tasks, timers, network services, FFI resources and VM cache status.

Syntax

Parameters

Parameters	Type	Required	Default value	Description
None	-	No	None	No parameters required.

Return Value

Type	Description
Object	Returns the runtime resource statistics object. See "Return Object Fields" below for fields.

Return object field

Field	Type	Must exist	Description
uptime	Int	Yes	The number of seconds the current BT process has been running, calculated by subtracting `start_time` from the current Unix timestamp.
threads	Int	Yes	Number of parallel threads available in the current system. `1` is returned when the read fails.
start_time	Int	Yes	BT process startup timestamp, in seconds.
io	Object	Yes	Configuration, number of activities, number of completions, number of rejections, and number of timeouts for the process-level I/O runtime and blocking pool.
task	Object	Yes	Whether the background task executor is started, the upper limit of the queue, the number of worker threads, the number of queues, the number of runs, the number of completions, and the number of rejections.
timer	Object	Yes	Whether the timer runtime is started, the number of active timers, the number of scheduling heap entries, the upper limit, and the single VM event queue upper limit.
net	Object	Yes	Network Web services, event services, bounded event queues, connection and message resource limits.
http	Object	Yes	HTTP client pool configuration, number of entries, hits, eliminations, creation failures, and slow calls.
mysql	Object	Yes	MySQL normal query connection pool configuration, number of DSN groups, number of connections, number of hits, number of eliminations, number of creation failures and number of slow calls.
bytes	Object	Yes	Bytes Buffer limit and configuration error.
ffi	Object	Yes	Whether FFI is enabled, the number of open dynamic libraries, the number of Buffers and the actual number of allocated bytes.
cache	Object	Yes	Current thread include Compilation cache and template fragment cache entry count, byte count, hit, invalidation, and eviction statistics.
permission	Object	Yes	Permission configuration snapshot, current actual allowed capabilities and number of permission denials.

ffi Field:

Field	Type	Must exist	Description
enabled	Bool	Yes	Whether the FFI feature is enabled for the current build.
open_libraries	Int	Yes	The number of dynamic libraries currently opened logically, the upper limit is 32.
buffers	Int	Yes	The current number of surviving FfiBuffers, the upper limit is 256.
buffer_bytes	Int	Yes	The actual total allocation of the current FfiBuffer after rounding up to 16 bytes, with an upper limit of 64 MiB.

I/O default configuration:

Environment variables	Default value	Description
BT_IO_WORKERS	Number of CPU threads, maximum 64	Number of shared Tokio runtime worker threads.
BT_IO_BLOCKING_WORKERS	Number of CPU threads, max 64	Number of bounded blocking pool worker threads.
BT_IO_BLOCKING_QUEUE	256, maximum 8192	blocking pool wait queue length.
BT_IO_TIMEOUT_MS	30000	Default synchronization wait timeout, in milliseconds.
BT_IO_SHUTDOWN_TIMEOUT_MS	1000	Blocking pool shutdown waiting time, in milliseconds.

io Main fields:

Field	Type	Must exist	Description
async_runtime_started	Bool	Yes	Shared Whether the Tokio runtime has been initialized.
async_active	Int	Yes	The number of asynchronous I/O tasks currently executing.
async_completed	Int	Yes	The number of asynchronous I/O tasks that have been completed.
async_failed	Int	Yes	The number of asynchronous I/O tasks that failed.
async_timeouts	Int	Yes	The number of timeouts that occurred while waiting synchronously for the results of an asynchronous task.
async_rejected	Int	Yes	The number of asynchronous tasks that were rejected due to runtime shutdown or scheduling failure.
blocking_pool_started	Bool	Yes	Whether the bounded blocking pool has been initialized.
blocking_queued	Int	Yes	The number of blocking tasks currently queued for execution.
blocking_running	Int	Yes	The number of blocking tasks currently being executed.
blocking_completed	Int	Yes	The number of completed blocking tasks.
blocking_rejected	Int	Yes	The number of blocking tasks that were rejected because the queue was full or the thread pool was closed.
blocking_timeouts	Int	Yes	The number of blocking task timeouts waiting for results.
blocking_shutdown	Bool	Yes	Whether the blocking pool has entered the shutdown state.
config	Object	Yes	I/O configuration snapshot, including `async_workers`, `blocking_workers`, `blocking_queue_limit`, `default_timeout_ms`, `shutdown_timeout_ms`.

io.config Fields:

Field	Type	Must exist	Description
async_workers	Int	Yes	Number of shared Tokio runtime worker threads.
blocking_workers	Int	Yes	Number of bounded blocking pool worker threads.
blocking_queue_limit	Int	Yes	blocking pool waiting queue length upper limit.
default_timeout_ms	Int	Yes	Default synchronization wait timeout, in milliseconds.
shutdown_timeout_ms	Int	Yes	blocking pool shutdown waiting time, in milliseconds.

task main fields:

Field	Type	Must exist	Description
executor_started	Bool	Yes	Whether the background task executor has been initialized.
queue_limit	Int	Yes	The upper limit of the background task waiting queue length.
workers	Int	Yes	Number of background task workers.
queued	Int	Yes	The number of tasks currently queued for execution.
running	Int	Yes	The number of tasks currently being executed.
completed	Int	Yes	The number of completed tasks.
rejected	Int	Yes	The number of tasks that were rejected because the queue was full or the executor was shut down.

timer main fields:

Field	Type	Must exist	Description
runtime_started	Bool	Yes	Whether the timer has been initialized during runtime.
active	Int	Yes	The number of currently active timers.
queued	Int	Yes	The number of timer entries in the current scheduling heap.
limit	Int	Yes	The maximum number of active timers allowed for the current process.
event_queue_limit	Int	Yes	Maximum single VM timer event queue length.

net Default configuration:

Environment Variables	Default Value	Description
BT_NET_EVENT_QUEUE	4096, maximum 65536	TCP, UDP, WebSocket Bounded queue length for background event delivery to the VM.
BT_NET_CONNECTION_LIMIT	4096, maximum 65536	Maximum number of single-protocol connections or sockets.
BT_NET_MESSAGE_LIMIT	1048576, maximum 16777216	The upper limit of single TCP/UDP/WebSocket message bytes.
BT_NET_WRITE_QUEUE	1024, maximum 8192	The length of the queue of pending writes for a single TCP/WebSocket connection.
BT_NET_IDLE_TTL_MS	0	TCP/WebSocket connection idle closing time, in milliseconds; 0 means not to actively close due to idleness.

net main fields:

Field	Type	Must exist	Description
runtime_started	Bool	Yes	Whether the network runtime has been initialized.
web_services	Int	Yes	The number of web services currently held by `net.listen({type:'web'})` or the web runner.
event_services	Int	Yes	The current number of TCP, UDP, and WebSocket event services.
event_queue_bounded	Bool	Yes	Whether to enable bounded network event queues. Currently fixed to `true`.
event_queue_limit	Int/Empty	Yes	Network event queue limit. `empty` when the event queue is not enabled.
event_queue_queued	Int	Yes	The number of network events currently waiting for distribution by the VM.
event_queue_sent	Int	Yes	The number of network events that were successfully delivered to the VM.
event_queue_rejected	Int	Yes	Number of network events that were rejected because the queue was full or the channel was closed.
connection_limit	Int	Yes	The maximum number of single-protocol connections or sockets.
message_limit	Int	Yes	The upper limit of bytes in a single message.
write_queue_limit	Int	Yes	Single connection write queue limit.
idle_ttl_ms	Int	Yes	TCP/WebSocket connection idle closing time, in milliseconds; `0` means closing this policy.

Bytes Default configuration:

Environment variable	Default value	Description
BT_BYTES_LIMIT	16777216, maximum 67108864	The maximum number of bytes buffered by a single Bytes.

bytes Main fields:

Field	Type	Must exist	Description
limit	Int	Yes	Single Bytes buffer upper limit, unit byte.
config_error	String/Empty	Yes	Bytes Configuration error text; `empty` when there is no error.

cache Main fields:

Field	Type	Must exist	Description
compiled_file_entries	Int	Yes	The number of current thread include/Web entry file compilation cache entries.
compiled_file_limit	Int	Yes	The upper limit of current thread file compilation cache entries.
compiled_file_bytes	Int	Yes	The estimated number of bytes in the current thread file compilation cache.
compiled_file_bytes_limit	Int	Yes	The estimated byte limit of the current thread file compilation cache.
compiled_file_hits	Int	Yes	Number of file compilation cache hits.
compiled_file_misses	Int	Yes	Number of file compilation cache misses.
compiled_file_invalidations	Int	Yes	The number of failures caused by changes in file metainformation, source code fingerprint, source code mode, compilation configuration, or bytecode format.
compiled_file_evictions	Int	Yes	The number of times the file compilation cache has been evicted due to the maximum number of entries or bytes being reached.
compiled_file_fingerprint_checks	Int	Yes	The number of times to perform content fingerprint checks on recently modified files.
template_fragment_entries	Int	Yes	Number of template fragment compilation cache entries for the current thread.
template_fragment_limit	Int	Yes	The upper limit of current thread template fragment cache entries.
template_fragment_bytes	Int	Yes	The estimated number of bytes of the current thread's template fragment cache.
template_fragment_bytes_limit	Int	Yes	The estimated byte limit of the current thread template fragment cache.
template_fragment_hits	Int	Yes	Number of template fragment cache hits.
template_fragment_misses	Int	Yes	Number of template fragment cache misses.
template_fragment_evictions	Int	Yes	The number of times the template fragment cache has been evicted due to the maximum number of entries or bytes being reached.
template_fragment_bypassed	Int	Yes	The number of times the template fragment is cached when it is too large or exceeds the cache capacity.
template_fragment_max_code_bytes	Int	Yes	The maximum number of source code bytes allowed to be cached for a single template fragment.

permission Default configuration:

Environment variable	Default value	Description
BT_PERMISSION_ALLOW	Not configured	List of allowed capabilities. After configuration, only the capabilities in the list are allowed; support `fs`, `process`, `net`, `http`, `mysql`, `device`, `env`, `desktop`, `all`, `none`.
BT_PERMISSION_DENY	Not configured	Deny capability list. Deny lists have higher priority than allow lists.

permission main fields:

Field	Type	Must exist	Description
denied	Int	Yes	The number of permission denials in the current process.
config	Object	Yes	Permission configuration snapshot. See the `permission.config` fields below.

permission.config Field:

Field	Type	Must exist	Description
allow_configured	Bool	Yes	Whether `BT_PERMISSION_ALLOW` is explicitly configured.
allow	Array	Yes	Capability name in the allow list; returns all capabilities if not configured.
deny	Array	Yes	Name of the capability in the deny list.
allowed	Array	Yes	The name of the currently allowed capability.
config_error	String/Empty	Yes	Permission configuration error text; `empty` when there is no error.

HTTP client pool default configuration:

Environment variable	Default value	Description
BT_HTTP_CLIENT_POOL	true	Whether to enable the HTTP client pool.
BT_HTTP_CLIENT_POOL_LIMIT	32, maximum 1024	Maximum number of client configuration groups to retain.
BT_HTTP_CLIENT_IDLE_TTL_MS	300000	client idle retention time, in milliseconds; 0 means not to be eliminated based on idle time.
BT_HTTP_SLOW_MS	0	Slow HTTP call log threshold, in milliseconds; 0 means off.

http main fields:

Field	Type	Must exist	Description
pool_started	Bool	Yes	Whether the HTTP client pool has been initialized.
entries	Int	Yes	The number of client entries in the current pool.
hits	Int	Yes	Number of pool hits.
misses	Int	Yes	Number of pool misses.
created	Int	Yes	Number of client creations.
evicted	Int	Yes	The number of client evictions.
bypassed	Int	Yes	The number of times the pool was bypassed due to shutdown or cookie storage semantics.
build_failed	Int	Yes	Number of client creation failures.
slow_calls	Int	Yes	The number of slow calls exceeding `BT_HTTP_SLOW_MS`.
config	Object	Yes	The current HTTP client pool configuration. See the `http.config` fields below.

http.config Fields:

Field	Type	Must exist	Description
enabled	Bool	Yes	Whether to enable the HTTP client pool.
pool_limit	Int	Yes	The maximum number of client configuration groups to retain.
idle_ttl_ms	Int	Yes	client idle retention time, in milliseconds; `0` means not to be eliminated based on idle time.
slow_ms	Int	Yes	Slow HTTP call log threshold, in milliseconds; `0` means closed.
config_error	String/Empty	Yes	HTTP client pool configuration error text; `empty` if there is no error.

MySQL common query connection pool default configuration:

Environment variable	Default value	Description
BT_MYSQL_POOL	true	Whether to enable the common query global connection pool.
BT_MYSQL_POOL_LIMIT	16, maximum 256	Maximum number of DSN packets to retain.
BT_MYSQL_POOL_MIN_CONNECTIONS	0	Minimum number of connections per connection pool.
BT_MYSQL_POOL_MAX_CONNECTIONS	8, maximum 1024	Maximum number of connections per connection pool.
BT_MYSQL_POOL_IDLE_TTL_MS	300000	Connection pool idle retention time, in milliseconds; 0 means no elimination based on idle time.
BT_MYSQL_CONNECT_TIMEOUT_MS	5000	Get the connection timeout, in milliseconds.
BT_MYSQL_QUERY_TIMEOUT_MS	30000	Synchronization wait timeout for a single SQL call, in milliseconds.
BT_MYSQL_SLOW_MS	0	Slow MySQL call log threshold, in milliseconds; 0 means closed.

mysql main fields:

Field	Type	Must exist	Description
pool_started	Bool	Yes	Whether the MySQL global connection pool has been initialized.
entries	Int	Yes	The number of DSN packets in the current pool, excluding DSN plaintext.
connections	Int	Yes	The total number of open connections in the current SQLx pool.
idle_connections	Int	Yes	Total number of idle connections in the current SQLx pool.
hits	Int	Yes	Number of pool hits.
misses	Int	Yes	Number of pool misses.
created	Int	Yes	Number of pool creations.
evicted	Int	Yes	Number of pool evictions.
bypassed	Int	Yes	The number of times the pool was bypassed due to closing the global pool.
build_failed	Int	Yes	Number of pool creation failures.
slow_calls	Int	Yes	The number of slow calls exceeding `BT_MYSQL_SLOW_MS`.
transactions_active	Int	Yes	The current number of active transactions.
transactions_started	Int	Yes	Number of transactions started.
transactions_committed	Int	Yes	Number of transaction commits.
transactions_rolled_back	Int	Yes	Number of transaction rollbacks, including the default rollback performed by `close()` on active transactions.
transactions_closed	Int	Yes	`close()` Number of active transactions successfully closed.
transactions_failed	Int	Yes	The number of transaction start, commit, rollback, or close failures.
config	Object	Yes	The current MySQL pool configuration. See the `mysql.config` fields below.

mysql.config Field:

Field	Type	Must exist	Description
enabled	Bool	Yes	Whether to enable the normal query global connection pool.
pool_limit	Int	Yes	The maximum number of DSN groups to retain.
min_connections	Int	Yes	Minimum number of connections per connection pool.
max_connections	Int	Yes	The maximum number of connections per connection pool.
idle_ttl_ms	Int	Yes	The idle retention time of the connection pool, in milliseconds; `0` means that it will not be eliminated according to the idle time.
connect_timeout_ms	Int	Yes	Get the connection timeout, in milliseconds.
query_timeout_ms	Int	Yes	Synchronization wait timeout for a single SQL call, in milliseconds.
slow_ms	Int	Yes	Slow MySQL call log threshold, in milliseconds; `0` means closed.
config_error	String/Empty	Yes	MySQL pool configuration error text; `empty` if there is no error.

Code Examples

Notes

BT.stats() reads statistics on demand and does not maintain heavy counts during normal VM instruction execution.
cache statistics only reflect the VM thread local cache of the current thread; in a Web multi-worker scenario, each worker will maintain its own cache.
Only mtime, length and version are checked when the file compilation cache is stably hit; recently modified files will be reviewed at low frequency for content fingerprints to avoid executing old bytecode after rapid rewriting of the same length.
net.event_queue_rejected greater than 0 indicates that the network event queue is overloaded, TCP/WebSocket message events will trigger the connection to be closed, and UDP messages will be discarded.

- http.bypassed growth usually indicates that the HTTP client pool is turned off, or that cookie_store(true) is requested to be enabled.

- mysql.entries, mysql.connections and transaction statistics do not contain DSN plaintext or passwords; connection failure and slow call logs also avoid printing DSN passwords.

- bytes.limit controls the maximum length of a single Bytes that scripts and I/O boundaries can create to avoid unlimited growth of the binary buffer.

ffi statistics only maintain open Library and Buffer resource quotas, not the cumulative number of native function call hot paths or cache hits.

- permission.denied greater than 0 indicates that the script triggered a capability that is denied by the current configuration; permission denial is an explicit runtime error and does not return empty.

- Misconfiguration of I/O environment variables will result in an error the first time the relevant I/O capability is used, without silently falling back to dangerous default values.