title description
Configuration Server configuration keys reference documentation.

This page describes methods for configuring QuestDB server settings. Configuration can be set either:

  • In the server.conf configuration file available in the root directory
  • Using environment variables

When a key is absent from both the configuration file and the environment variables, the default value is used. Configuration of logging is handled separately and details of configuring this behavior can be found at the logging section below.

Environment variables

All settings in the configuration file can be set or overridden using environment variables. If a key is set in both the server.conf file and via an environment variable, the environment variable will take precedence and the value in the server configuration file will be ignored.

To make these configuration settings available to QuestDB via environment variables, they must be in the following format:


1. QDB_<KEY_OF_THE_PROPERTY>

Where <KEY_OF_THE_PROPERTY> is equal to the configuration key name. To properly format a server.conf key as an environment variable it must have:

  1. QDB_ prefix
  2. uppercase characters
  3. all . period characters replaced with _ underscore

For example, the server configuration key for shared workers must be passed as described below:

server.conf key env var
shared.worker.count QDB_SHARED_WORKER_COUNT

:::note

QuestDB applies these configuration changes on startup and a running instance must be restarted in order for configuration changes to take effect

:::

Examples

The following configuration property customizes the number of worker threads shared across the application:


1. shared.worker.count=5



1. export QBD_SHARED_WORKER_COUNT=5

Docker

This section describes how configure QuestDB server settings when running QuestDB in a Docker container. A command to run QuestDB via Docker with default interfaces is as follows:


1. docker run -p 9000:9000 \
2. -p 9009:9009 \
3. -p 8812:8812 \
4. -p 9003:9003 \
5. questdb/questdb

This publishes the following ports:

The examples in this section change the default HTTP and REST API port from 9000 to 4000 for illustrative purposes, and demonstrate how to publish this port with a non-default property.

Environment variables

Server configuration can be passed to QuestDB running in Docker by using the -e flag to pass an environment variable to a container:


1. docker run -p 4000:4000 -e QBD_HTTP_BIND_TO=0.0.0.0:4000 questdb/questdb

Mounting a volume

A server configuration file can be provided by mounting a local directory in a QuestDB container. Given the following configuration file which overrides the default HTTP bind property:


1. http.bind.to=0.0.0.0:4000

Running the container with the -v flag allows for mounting the current directory to QuestDB’s conf directory in the container. With the server configuration above, HTTP ports for the web console and REST API will be available on localhost:4000:


1. docker run -v "$(pwd):/root/.questdb/conf" -p 4000:4000 questdb/questdb

To mount the full root directory of QuestDB when running in a Docker container, provide a the configuration in a conf directory:


1. http.bind.to=0.0.0.0:4000

Mount the current directory using the -v flag:


1. docker run -v "$(pwd):/root/.questdb/" -p 4000:4000 questdb/questdb

The current directory will then have data persisted to disk:


1. ├── conf
2. │  └── server.conf
3. ├── db
4. └── public

Keys and default values

This section lists the configuration keys available to QuestDB by topic or subsystem.

Shared worker

Shared worker threads service SQL execution subsystems and (in the default configuration) every other subsystem.

Property Default Description
shared.worker.count 2 Number of worker threads shared across the application. Increasing this number will increase parallelism in the application at the expense of CPU resources.
shared.worker.affinity Comma-delimited list of CPU ids, one per thread specified in shared.worker.count. By default, threads have no CPU affinity.
shared.worker.haltOnError false Toggle whether worker should stop on error.

Load balancing

This section describes configuration settings for the distribution of work by writer threads in a QuestDB instance.

Property Default Description
line.tcp.n.updates.per.load.balance 10000 Maximum number of updates in a given table since the last load balancing before triggering a new load balancing job.
line.tcp.max.load.ratio 1.9 Maximum load ratio (max loaded worker/min loaded worker) before QuestDB will attempt to rebalance the load between the writer workers.
line.tcp.max.uncommitted.rows 1000 Maximum number of uncommitted rows, note that rows will always be committed if they have been received line.tcp.maintenance.job.interval ms ago.
line.tcp.maintenance.job.interval 1000 Maximum amount of time in between maintenance jobs, these will commit any uncommited data.

Minimal HTTP server

This server runs embedded in a QuestDB instance by default and enables health checks of an instance via HTTP. It responds to all requests with a HTTP status code of 200 unless the QuestDB process dies.

Examples of how to use this server, along with expected responses, can be found on the health monitoring page.

Property Default Description
http.min.enabled true Enable Minimal HTTP server.
http.min.bind.to 0.0.0.0:9003 IPv4 address and port of the server. 0 means it will bind to all network interfaces. Otherwise IP address must by one of the existing network adaptors

HTTP server

This section describes configuration settings for the Web Console available by default on port 9000. For details on the use of this component, refer to the web console documentation page.

Property Default Description
http.enabled true Enable HTTP server.
http.connection.pool.initial.capacity 16 Initial size of pool of reusable objects that hold connection state. The pool should be configured to maximum realistic load so that it does not resize at runtime.
http.connection.string.pool.capacity 128 Initial size of the string pool shared by HttpHeaderParser and HttpMultipartContentParser.
http.multipart.header.buffer.size 512 HeaderParser buffer size in bytes.
http.multipart.idle.spin.count 10_000 How long the code accumulates incoming data chunks for column and delimiter analysis.
http.receive.buffer.size 1m Size of receive buffer.
http.request.header.buffer.size 64k Size of internal buffer allocated for HTTP request headers. The value is rounded up to the nearest power of 2. When HTTP request contains headers that exceed the buffer size server will disconnect the client with HTTP error in server log.
http.response.header.buffer.size 32k Size of the internal response buffer. The value will be rounded up to the nearest power of 2. The buffer size should be large enough to accommodate max size of server response headers.
http.worker.count 0 Number of threads in private worker pool. When value is 0, HTTP server will be using shared worker pool of the server. Values above 0 switch on private pool.
http.worker.affinity comma separated list of CPU core indexes. The number of items of this list must be equal to the worker count.
http.worker.haltOnError false Flag that indicates if worker thread must shutdown on unhandled error. We strongly recommend not to change default value.
http.send.buffer.size 2m Size of the internal send buffer. The larger than buffer size the fewer IO interruptions server is making at expense of memory usage per connection. There is a limit of send buffer size after which increasing it stops being useful in terms of performance. 2MB seems to be optimal value.
http.static.index.file.name index.html Name of index file for the Web Console.
http.frozen.clock false Sets the clock to always return zero. This configuration parameter is used for internal testing.
http.allow.deflate.before.send false Enable / disable Gzip compression of outgoing data.
http.keep-alive.timeout 5 Used together with http.keep-alive.max to set the value of HTTP Keep-Alive response header. This instructs browser to keep TCP connection open. Has to be 0 when http.version is set to HTTP/1.0.
http.keep-alive.max 10_000 See http.keep-alive.timeout. Has to be 0 when http.version is set to HTTP/1.0.
http.static.public.directory public The name of directory for public web site.
http.net.active.connection.limit 256 The number of simultaneous TCP connection to the HTTP server. The rationale of the value is to control server memory consumption.
http.net.event.capacity 1024 Internal IO event queue capacity (EPoll, KQqueu, Select). Size of these queues must be larger than http.net.active.connection.limit.
http.net.io.queue.capacity 1024 Internal IO queue of HTTP server. Size of this queue must be larger than http.net.active.connection.limit. Queue size smaller than active connection max will substantially slow down the server by increasing wait times. Queue larger than connection max reduces wait time to 0.
http.net.idle.connection.timeout 300000 TCP connection idle timeout in milliseconds. Connection is closed by HTTP server when this timeout lapses.
http.net.interest.queue.capacity 1024 Internal queue size. This is also related to http.net.active.connection.limit in a way that sizes larger than connection max remove any waiting.
http.net.listen.backlog 256 Backlog argument value for listen() call.
http.net.snd.buf.size 2m Maximum send buffer size on each TCP socket. If value is -1 socket send buffer remains unchanged from OS default.
http.net.rcv.buf.size 2m Maximum receive buffer size on each TCP socket. If value is -1 socket receive buffer remains unchanged from OS default.
http.text.date.adapter.pool.capacity 16 Size of date adaptor pool. This should be set to the anticipated maximum number of DATE fields a text input can have. The pool is assigned to connection state and is reused alongside of connection state object.
http.text.json.cache.limit 16384 JSON parser cache limit. Cache is used to compose JSON elements that have been broken up by TCP protocol. This value limits the maximum length of individual tag or tag value.
http.text.json.cache.size 8192 Initial size of JSON parser cache. The value must not exceed http.text.json.cache.limit and should be set to avoid cache resizes at runtime.
http.text.max.required.delimiter.stddev 0.1222d The maximum standard deviation value for the algorithm that calculates text file delimiter. Usually when text parser cannot recognise the delimiter it will log the calculated and maximum standard deviation for the delimiter candidate.
http.text.max.required.line.length.stddev 0.8 Maximum standard deviation value for the algorithm that classifies input as text or binary. For the values above configured stddev input will be considered binary.
http.text.metadata.string.pool.capacity 128 The initial size of pool for objects that wrap individual elements of metadata JSON, such as column names, date pattern strings and locale values.
http.text.roll.buffer.limit 4m The limit of text roll buffer. See http.text.roll.buffer.size for description.
http.text.roll.buffer.size 1024 Roll buffer is a structure in text parser that holds a copy of a line that has been broken up by TCP. The size should be set to the maximum length of text line in text input.
http.text.analysis.max.lines 1000 Number of lines to read on CSV import for heuristics which determine column names & types. Lower line numbers may detect CSV schemas quicker, but possibly with less accuracy. 1000 lines is the maximum for this value.
http.text.lexer.string.pool.capacity 64 The initial capacity of string fool, which wraps STRING column types in text input. The value should correspond to the maximum anticipated number of STRING columns in text input.
http.text.timestamp.adapter.pool.capacity 64 Size of timestamp adaptor pool. This should be set to the anticipated maximum number of TIMESTAMP fields a text input can have. The pool is assigned to connection state and is reused alongside of connection state object
http.text.utf8.sink.size 4096 Initial size of UTF-8 adaptor sink. The value should correspond the maximum individual field value length in text input
http.json.query.connection.check.frequency 1_000_000 The value to throttle check if client socket has been disconnected. It is not recommended to change this value
http.json.query.float.scale 10 The scale value of string representation of FLOAT values
http.json.query.double.scale 12 The scale value of string representation of DOUBLE values
http.bind.to 0.0.0.0:9000 IP address and port of HTTP server. 0 means that http server will bind to all network interfaces. You can specify IP address of any individual network interface on your system
http.security.readonly false Forces HTTP read only mode when true, which disables commands which modify the data or data structure.
http.security.max.response.rows Long.MAX_VALUE Limit the number of response rows over HTTP.
http.security.interrupt.on.closed.connection true Switch to enable termination of SQL processing if the HTTP connection is closed. The mechanism affects performance so the connection is only checked after http.security.interruptor.iterations.per.check calls are made to the check method. The mechanism also reads from the input stream and discards it since some HTTP clients send this as a keep alive in between requests, http.security.interruptor.buffer.size denotes the size of the buffer for this.
http.security.interruptor.iterations.per.check 2000000 Number of internal iterations such as loops over data before checking if the HTTP connection is still open
http.security.interruptor.buffer.size 32 Size of buffer to read from HTTP connection. If this buffer returns zero and the HTTP client is no longer sending data, SQL processing will be terminated.
http.server.keep.alive true If set to false, the server will disconnect the client after completion of each request.
http.version HTTP/1.1 Protocol version, other supported value is HTTP/1.0.

Cairo engine

This section describes configuration settings for the Cairo SQL engine in QuestDB.

Property Default Description
cairo.sql.copy.root null Input root directory for backups.
cairo.sql.backup.root null Output root directory for backups.
cairo.sql.backup.dir.datetime.format null Date format for backup directory.
cairo.sql.backup.dir.tmp.name tmp Name of tmp directory used during backup.
cairo.sql.backup.mkdir.mode 509 Permission used when creating backup directories.
cairo.root db Directory for storing db tables and metadata. This directory is inside the server root directory provided at startup.
cairo.commit.mode nosync How changes to table are flushed to disk upon commit. Choices: nosync, async (flush call schedules update, returns immediately), sync (waits for flush to complete).
cairo.create.as.select.retry.count 5 Number of types table creation or insertion will be attempted.
cairo.default.map.type fast Type of map used. Options: fast (speed at the expense of storage), compact.
cairo.default.symbol.cache.flag false When true, symbol values will be cached on Java heap.
cairo.default.symbol.capacity 256 Specifies approximate capacity for SYMBOL columns. It should be equal to number of unique symbol values stored in the table and getting this value badly wrong will cause performance degradation. Must be power of 2.
cairo.file.operation.retry.count 30 Number of attempts to open files.
cairo.idle.check.interval 300000 Frequency of writer maintenance job in milliseconds.
cairo.inactive.reader.ttl -120000 Frequency of reader pool checks for inactive readers in milliseconds.
cairo.inactive.writer.ttl -600000 Frequency of writer pool checks for inactive writers in milliseconds.
cairo.index.value.block.size 256 Approximation of number of rows for a single index key, must be power of 2.
cairo.max.swap.file.count 30 Number of attempts to open swap files.
cairo.mkdir.mode 509 File permission mode for new directories.
cairo.parallel.index.threshold 100000 Minimum number of rows before allowing use of parallel indexation.
cairo.reader.pool.max.segments 5 Number of attempts to get TableReader.
cairo.spin.lock.timeout 1_000_000 Timeout when attempting to get BitmapIndexReaders in microseconds.
cairo.cache.rows 16 Number of rows for the query cache.
cairo.cache.blocks 4 Number of blocks for the query cache.
cairo.character.store.capacity 1024 Size of the CharacterStore.
cairo.character.store.sequence.pool.capacity 64 Size of the CharacterSequence pool.
cairo.column.pool.capacity 4096 Size of the Column pool in the SqlCompiler.
cairo.compact.map.load.factor 0.7 Load factor for CompactMaps.
cairo.expression.pool.capacity 8192 Size of the ExpressionNode pool in SqlCompiler.
cairo.fast.map.load.factor 0.5 Load factor for all FastMaps.
cairo.sql.join.context.pool.capacity 64 Size of the JoinContext pool in SqlCompiler.
cairo.lexer.pool.capacity 2048 Size of FloatingSequence pool in GenericLexer.
cairo.sql.map.key.capacity 2m Key capacity in FastMap and CompactMap.
cairo.sql.map.max.resizes 2^31 Number of map resizes in FastMap and CompactMap before a resource limit exception is thrown, each resize doubles the previous size.
cairo.sql.map.page.size 4m Memory page size for FastMap and CompactMap.
cairo.sql.map.max.pages 2^31 Memory max pages for CompactMap.
cairo.model.pool.capacity 1024 Size of the QueryModel pool in the SqlCompiler.
cairo.sql.sort.key.page.size 4m Memory page size for storing keys in LongTreeChain.
cairo.sql.sort.key.max.pages 2^31 Max number of pages for storing keys in LongTreeChain before a resource limit exception is thrown.
cairo.sql.sort.light.value.page.size 1048576 Memory page size for storing values in LongTreeChain.
cairo.sql.sort.light.value.max.pages 2^31 Max pages for storing values in LongTreeChain.
cairo.sql.hash.join.value.page.size 16777216 Memory page size of the slave chain in full hash joins.
cairo.sql.hash.join.value.max.pages 2^31 Max pages of the slave chain in full hash joins.
cairo.sql.latest.by.row.count 1000 Number of rows for LATEST BY.
cairo.sql.hash.join.light.value.page.size 1048576 Memory page size of the slave chain in light hash joins.
cairo.sql.hash.join.light.value.max.pages 2^31 Max pages of the slave chain in light hash joins.
cairo.sql.sort.value.page.size 16777216 Memory page size of file storing values in SortedRecordCursorFactory.
cairo.sql.sort.value.max.pages 2^31 Max pages of file storing values in SortedRecordCursorFactory.
cairo.work.steal.timeout.nanos 10_000 Latch await timeout in nanos for stealing indexing work from other threads.
cairo.parallel.indexing.enabled true Allows parallel indexation. Works in conjunction with cairo.parallel.index.threshold.
cairo.sql.join.metadata.page.size 16384 Memory page size for JoinMetadata file.
cairo.sql.join.metadata.max.resizes 2^31 Number of map resizes in JoinMetadata before a resource limit exception is thrown, each resize doubles the previous size.
cairo.sql.analytic.column.pool.capacity 64 Size of AnalyticColumn pool in SqlParser.
cairo.sql.create.table.model.pool.capacity 16 Size of CreateTableModel pool in SqlParser.
cairo.sql.column.cast.model.pool.capacity 16 Size of CreateTableModel pool in SqlParser.
cairo.sql.rename.table.model.pool.capacity 16 Size of RenameTableModel pool in SqlParser.
cairo.sql.with.clause.model.pool.capacity 128 Size of WithClauseModel pool in SqlParser.
cairo.sql.insert.model.pool.capacity 64 Size of InsertModel pool in SqlParser.
cairo.sql.copy.model.pool.capacity 32 Size of CopyModel pool in SqlParser.
cairo.sql.copy.buffer.size 2m Size of buffer used when copying tables.
cairo.sql.double.cast.scale 12 Maximum number of decimal places that types cast as doubles have
cairo.sql.float.cast.scale 4 Maximum number of decimal places that types cast as floats have
cairo.sql.copy.formats.file /text_loader.json Name of file with user’s set of date and timestamp formats.
cairo.date.locale en The locale to handle date types
cairo.timestamp.locale en The locale to handle timestamp types

Postgres wire protocol

This section describes configuration settings for client connections using PostreSQL wire protocol.

Property Default Description
pg.enabled true Configuration for enabling or diabling the Postres interface
pg.net.active.connection.limit 10 The number of simultaneous PostgreSQL connections to the server. This value is intended to control server memory consumption.
pg.net.bind.to 0.0.0.0:8812 IP address and port of PostgreSQL server. 0 means that the server will bind to all network interfaces. You can specify IP address of any individual network interface on your system
pg.net.event.capacity 1024 Internal IO event queue capacity (EPoll, KQqueu, Select). Size of these queues must be larger than active.connection.limit
pg.net.io.queue.capacity 1024 Internal IO queue of the server. The size of this queue must be larger than the active.connection.limit. A queue size smaller than active connection max will substantially slow down the server by increasing wait times. A queue larger than connection max reduces wait time to 0.
pg.net.idle.timeout 300000 Connection idle timeout in milliseconds. Connections are closed by the server when this timeout lapses.
pg.net.interest.queue.capacity 1024 Internal queue size. This is also related to active.connection.limit in a way that sizes larger than connection max remove any waiting.
pg.net.listen.backlog 50000 Backlog argument value for listen() call.
pg.net.recv.buf.size -1 Maximum send buffer size on each TCP socket. If value is -1 socket send buffer remains unchanged from OS default.
pg.net.send.buf.size -1 Maximum receive buffer size on each TCP socket. If value is -1, the socket receive buffer remains unchanged from OS default.
pg.character.store.capacity 4096 Size of the CharacterStore
pg.character.store.pool.capacity 64 Size of the CharacterStore pool capacity
pg.connection.pool.capacity 64 The maximum amount of pooled connections this interface may have
pg.password quest Postgres database password
pg.user admin Postgres database username
pg.factory.cache.column.count 16 Number of columns to cache SQL execution plan against text to speed up execution. This value must be 2n (power of two).
pg.factory.cache.row.count 16 Number of rows to cache for SQL execution plan against text to speed up execution. This value must be 2n (power of two)
pg.idle.recv.count.before.giving.up 10000 Number of times to poll receive method that returns zero data before deciding what to do next with the connection
pg.idle.send.count.before.giving.up 10000 Number of times to poll send method that returns zero data before deciding what to do next with the connection
pg.max.blob.size.on.query 512k For binary values, clients will receive an error when requesting blob sizes above this value
pg.recv.buffer.size 1M Size of the buffer for receiving data
pg.send.buffer.size 1M Size of the buffer for sending data
pg.date.locale en The locale to handle date types
pg.timestamp.locale en The locale to handle timestamp types
pg.worker.count 2 Number of dedicated worker threads assigned to write data. When 0, the writer jobs will use the shared pool.
pg.worker.affinity -1,-1 Comma-separated list of thread numbers which should be pinned for Postgres ingestion. Example line.tcp.worker.affinity=1,2,3.
pg.halt.on.error false Whether ingestion should stop upon internal error

InfluxDB line protocol (TCP)

This section describes ingestion settings for incoming messages using InfluxDB line protocol over TCP.

Property Default Description
line.tcp.auth.db.path Path which points to the authentication db file.
line.tcp.default.partition.by DAY The default partitioning strategy applied to new tables dynamically created by sending records via ILP created
line.tcp.enabled true Enable or disable line protocol over TCP.
line.tcp.net.active.connection.limit 10 The number of simultaneous connections to the server. This value is intended to control server memory consumption.
line.tcp.net.bind.to 0.0.0.0:9009 Internal IO event queue capacity (EPoll, KQqueu, Select). Size of these queues must be larger than active.connection.limit.
line.tcp.net.event.capacity 1024 Internal IO queue of the server. The size of this queue must be larger than the active.connection.limit. A queue size smaller than active connection max will substantially slow down the server by increasing wait times. A queue larger than connection max reduces wait time to 0.
line.tcp.net.io.queue.capacity 1024 Connection idle timeout in milliseconds. Connections are closed by the server when this timeout lapses.
line.tcp.net.idle.timeout 300000 Internal queue size. This is also related to active.connection.limit in a way that sizes larger than connection max remove any waiting.
line.tcp.net.interest.queue.capacity 1024 Backlog argument value for listen() call.
line.tcp.net.listen.backlog 50000 Maximum send buffer size on each TCP socket. If value is -1 socket send buffer remains unchanged from OS default.
line.tcp.net.recv.buf.size -1 Maximum receive buffer size on each TCP socket. If value is -1, the socket receive buffer remains unchanged from OS default.
line.tcp.connection.pool.capacity 64 The maximum amount of pooled connections this interface may have
line.tcp.timestamp n Input timestamp resolution. Possible values are n, u, ms, s and h.
line.tcp.msg.buffer.size 2048 Size of the buffer read from queue. Maximum size of write request, regardless of the number of measurements.
line.tcp.max.measurement.size 2048 Maximum size of any measurement.
line.tcp.writer.queue.size 128 Size of the queue between network IO and writer jobs. Each queue entry represents a measurement.
line.tcp.worker.count 0 Number of dedicated worker threads assigned to write data. When 0, the writer jobs will use the shared pool.
line.tcp.worker.affinity 0 Comma-separated list of thread numbers which should be pinned for line protocol ingestion over TCP. Example line.tcp.worker.affinity=1,3,4.
line.tcp.halt.on.error false Whether ingestion should stop upon internal error

InfluxDB line protocol (UDP)

This section describes ingestion settings for incoming messages using InfluxDB line protocol over UDP.

Property Default Description
line.udp.join 232.1.2.3 Multicast address receiver joins. This values is ignored when receiver is in “unicast” mode.
line.udp.bind.to 0.0.0.0:9009 IP address of the network interface to bind listener to and port. By default UDP receiver listens on all network interfaces.
line.udp.commit.rate 1000000 For packet bursts the number of continuously received messages after which receiver will force commit. Receiver will commit irrespective of this parameter when there are no messages.
line.udp.msg.buffer.size 2048 Buffer used to receive single message. This value should be roughly equal to your MTU size.
line.udp.msg.count 10000 Only for Linux. On Linix QuestDB will use recvmmsg(). This is the max number of messages to receive at once.
line.udp.receive.buffer.size 8388608 UDP socket buffer size. Larger size of the buffer will help reduce message loss during bursts.
line.udp.enabled true Flag to enable or disable UDP receiver.
line.udp.own.thread false When “true” UDP receiver will use its own thread and busy spin that for performance reasons. “false” makes receiver use worker threads that do everything else in QuestDB.
line.udp.own.thread.affinity -1 -1 does not set thread affinity. OS will schedule thread and it will be liable to run on random cores and jump between the. 0 or higher pins thread to give core. This property is only valid when UDP receiver uses own thread.
line.udp.unicast false When true, UDP will me unicast. Otherwise multicast.
line.udp.timestamp n Input timestamp resolution. Possible values are n, u, ms, s and h.
line.udp.commit.mode nosync Commit durability. Available values are nosync, sync and async.

Telemetry

QuestDB sends anonymized telemetry data with information about usage which helps us improve the product over time. We do not collect any personally-identifying information, and we do not share any of this data with third parties.

Property Default Description
telemetry.enabled true Enable / disable anonymous usage metrics collection.

Logging

The logging behavior of QuestDB may be set in dedicated configuration files or by environment variables. This section describes how to configure logging using these methods.

Configuration file

Logs may be configured via a dedicated file named log-stdout.conf.


1. # list of configured writers
2. writers=file,stdout

4. # file writer
5. #w.file.class=io.questdb.log.LogFileWriter
6. #w.file.location=questdb-debug.log
7. #w.file.level=INFO,ERROR

9. # stdout
10. w.stdout.class=io.questdb.log.LogConsoleWriter
11. w.stdout.level=INFO,ERROR

QuestDB will look for /log-stdout.conf on the classpath unless this name is overridden via a “system” property: -Dout=/something_else.conf.

Docker

When mounting a volume to a Docker container, a logging configuration file may be provided in the container located at /conf/log.conf. For example, a file with the following contents can be created:


1. # list of configured writers
2. writers=file,stdout,http.min

4. # file writer
5. w.file.class=io.questdb.log.LogFileWriter
6. w.file.location=questdb-docker.log
7. w.file.level=INFO,ERROR,DEBUG

9. # stdout
10. w.stdout.class=io.questdb.log.LogConsoleWriter
11. w.stdout.level=INFO

13. # min http server, used monitoring
14. w.http.min.class=io.questdb.log.LogConsoleWriter
15. w.http.min.level=ERROR
16. w.http.min.scope=http-min-server

The current directory can be mounted:


1. docker run -p 9000:9000 -v "$(pwd):/root/.questdb/" questdb/questdb

The container logs will be written to disk using the logging level and file name provided in the conf/log.conf file, in this case in ./questdb-docker.log.

Environment variables

Values in the log-stdout.conf file can be overridden with environment variables. All configuration keys must be formatted as described in the environment variables section above.

For example, to set logging on ERROR level only:


1. w.stdout.level=ERROR



1. export QDB_LOG_W_STDOUT_LEVEL=ERROR

Debug

QuestDB logging can be quickly forced globally to DEBUG via either providing the java option -Debug or setting the environment variable QDB_DEBUG=true.