Skip to main content
dt.options is a namespace object that stores all datatable runtime configuration. You can read any option by attribute access and set it by assignment. Changes take effect immediately and persist for the lifetime of the Python session. 
import datatable as dt

# Read a value
print(dt.options.nthreads)

# Set a value
dt.options.nthreads = 4
You can also call dt.options.describe() to print all current values with their defaults and documentation.

​
Context manager

Use dt.options.context() to temporarily change options inside a with block. The original values are restored automatically when the block exits, even if an exception is raised. 
with dt.options.context(nthreads=1):
    result = DT[:, dt.sum(f.value)]  # runs single-threaded

# nthreads is back to its previous value here

​
Resetting options

# Reset a single option to its default
del dt.options.nthreads

# Reset all options at once
dt.options.reset()

​
nthreads

​
nthreads
int
Number of threads used for all parallel computations. Defaults to the number of logical CPU cores reported by the operating system.
  • Set to 1 to force single-threaded execution.
  • Set to 0 to restore the default (hardware concurrency).
  • Negative values request fewer threads than the maximum (e.g., -2 means “all cores minus 2”).
dt.options.nthreads      # read current value
dt.options.nthreads = 8  # use 8 threads
dt.options.nthreads = 0  # restore default

​
display group

Options that control how frames are rendered in the console or a notebook.
​
display.allow_unicode
bool
Whether unicode characters are allowed in frame display output. Disable on terminals that cannot render unicode.
​
display.head_nrows
int
Number of rows shown at the top of a truncated frame view.
​
display.tail_nrows
int
Number of rows shown at the bottom of a truncated frame view.
​
display.max_nrows
int
Row count threshold above which the frame display is truncated. Frames with fewer rows are displayed in full.
​
display.max_column_width
int
Maximum character width of any column in the rendered output. Wider values are truncated with an ellipsis.
​
display.interactive
bool
Enable or disable the interactive (scrollable) frame viewer. When enabled, large frames are shown in a terminal pager.
​
display.use_colors
bool
Whether ANSI color codes are used in console output. Disable when piping output to a file or a tool that does not understand ANSI.
dt.options.display.max_nrows        = 30
dt.options.display.max_column_width = 50
dt.options.display.use_colors       = False

​
frame group

Options that control default column naming for new frames.
​
frame.names_auto_prefix
str
Prefix used when auto-generating column names. Defaults to "C", producing names like C0, C1, C2, …
​
frame.names_auto_index
int
Starting index for auto-generated column names. Defaults to 0.
dt.options.frame.names_auto_prefix = "col"
dt.options.frame.names_auto_index  = 1
# New unnamed columns will be named col1, col2, ...

​
fread group

Options that affect the behavior of dt.fread().
​
fread.parse_dates
bool
Whether fread should automatically recognize and parse date fields. Disable to keep date-like columns as strings.
​
fread.parse_times
bool
Whether fread should automatically recognize and parse time/timestamp fields.
​
fread.log.escape_unicode
bool
Whether unicode characters in fread log messages are escaped.
dt.options.fread.parse_dates = False  # keep date columns as strings
dt.options.fread.parse_times = False

​
progress group

Options controlling the progress bar shown during long-running operations.
​
progress.enabled
bool
Master switch for progress reporting. Set to False to suppress all progress bars.
​
progress.min_duration
float
Minimum task duration (in seconds) before a progress bar is displayed. Tasks shorter than this threshold show no progress bar.
​
progress.updates_per_second
float
How many times per second the progress bar is redrawn.
​
progress.clear_on_success
bool
Whether to erase the progress bar from the terminal once a task finishes successfully.
​
progress.allow_interruption
bool
Whether long-running datatable tasks can be interrupted with Ctrl+C.
​
progress.callback
callable | None
A custom progress-reporting function. When set, datatable calls this function instead of drawing the built-in progress bar. The function receives a progress value in [0, 1].
dt.options.progress.enabled       = False  # silence all progress bars
dt.options.progress.min_duration  = 2.0    # only show for tasks > 2 s
dt.options.progress.clear_on_success = True

​
debug group

Options for logging internal datatable operations, useful for performance profiling and troubleshooting.
​
debug.enabled
bool
Enable or disable debug logging. When True, datatable logs each internal function call.
​
debug.report_args
bool
Whether to include function/method arguments in debug log messages.
​
debug.arg_max_size
int
Maximum number of characters printed per argument value in debug log messages.
​
debug.logger
object | None
A custom logger object. Must have a .debug(msg) method. When None, debug output is written to sys.stdout.
import logging

logging.basicConfig(level=logging.DEBUG)
logger = logging.getLogger("datatable")

dt.options.debug.enabled     = True
dt.options.debug.logger      = logger
dt.options.debug.report_args = True
Enabling debug.enabled can produce a large volume of output during normal operations. It is recommended only for targeted troubleshooting.

Build docs developers (and LLMs) love

Get started for freeTalk to us