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๐Ÿชต Changelog

1.5.x Releases

This is the current release cycle, so stay tuned for future releases!

v1.5.3 โ€“ v1.5.5

  • Pipes now support syncing dictionaries and lists.
    Complex columns (dicts or lists) will now be preserved:
import meerschaum as mrsm
pipe = mrsm.Pipe('a', 'b')
pipe.sync([{'a': {'b': 1}}])
df = pipe.get_data()
# {'b': 1}

You can also force strings to be parsed by setting the data type to json:

import meerschaum as mrsm
pipe = mrsm.Pipe(
    'foo', 'bar',
    columns = {'datetime': 'id'},
    dtypes = {'data': 'json', 'id': 'Int64'},
docs = [{'id': 1, 'data': '{"foo": "bar"}'}]
df = pipe.get_data()
# {'foo': 'bar'}

For PostgreSQL-like databases (e.g. TimescaleDB), this is stored as JSONB under the hood. For all others, it's stored as the equivalent for TEXT.

  • Fixed determining the version when installing plugins.
    Like the required list, the __version__ string must be explicitly set in order for the correct version to be determined.

  • Automatically cast postgres to postgresql
    When a SQLConnector is built with a flavor of postgres, it will be automatically set to postgresql.

v1.5.0 โ€“ v1.5.2

  • Pipes may now use integers for the datetime column.
    If you use an auto-incrementing integer as your primary key, you may now use that column as your pipe's datetime column, just specify the dtype as an Int64:
import meerschaum as mrsm
pipe = mrsm.Pipe(
    'foo', 'bar',
    instance = 'sql:memory',
    columns = {
        'datetime': 'id',
    dtypes = {
        'id': 'Int64',
pipe.sync([{'id': 1, 'foo': 'bar'}])
pipe.sync([{'id': 2, 'foo': 'baz'}])

This applies the same incremental range filtering logic as is normally done on the datetime axis.

  • Allow for multiple plugins directories.
    You may now set multiple directories for MRSM_PLUGINS_DIR. All of the plugins contained in each directory will be symlinked together into a single plugins namespace. To do this, just set MRSM_PLUGINS_DIR to a JSON-encoded list:
export MRSM_PLUGINS_DIR='["./plugins_1", "./plugins_2"]'
  • Better Windows support.
    At long last, the color issues plaguing Windows users have finally been resolved. Additionally, support for background jobs has been fixed on Windows, though the daemonization library I use is pretty hacky and doesn't make for the smoothest experience. But at least it works now!

  • Fixed unsafe TAR extraction.
    A PR about unsafe use of tar.extractall() brought this issue to light.

  • Fixed the blank logs bug in show logs.
    Backtracking a couple lines before following the rest of the logs has been fixed.

  • Requirements may include brackets.
    Python packages listed in a plugin's requirements list may now include brackets (e.g. meerschaum[api]).

  • Enforce 1000 row limit in SQLConnector.to_sql() for SQLite.
    When inserting rows, the chunksize of 1000 is enforced for SQLite (was previously enforced only for reading).

  • Patch parameters from --params in edit pipes and register pipes.
    When editing or registering pipes, the value of --params will now be patched into the pipe's parameters. This should be very helpful when scripting.

  • Fixed edit users.
    This really should have been fixed a long time ago. The action edit users was broken due to a stray import left over from a major refactor.

  • Fixed a regex bug when cleaning up packages.

  • Removed show gui and show modules.

1.4.x Releases

The 1.4.x series brought some incredible, stable releases, and the highlight feature was in-place SQL syncs for massive performance improvement. The addition of temporary to Pipes also made using pipes in projects more accessible.


  • Added flag temporary to Pipe (and --temporary).
    Pipes built with temporary=True, will not create instance tables (pipes, users, and plugins) or be able to modify registration. This is particularly useful when creating pipes from existing tables when automatic registration is not desired.
import meerschaum as mrsm
import pandas as pd
conn = mrsm.get_connector('sql:temp', uri='postgresql://user:pass@localhost:5432/db')

### Simulating an existing table.
table_name = 'my_table'
    pd.DataFrame([{'id_column': 1, 'value': 1.0}]),
    name = table_name,

### Create a temporary pipe with the existing table as its target.
pipe = mrsm.Pipe(
    'foo', 'bar',
    target = table_name,
    temporary = True,
    instance = conn,
    columns = {
        'id': 'id_column',

docs = [
        "id_column": 1,
        "value": 123.456,
        "new_column": "hello, world!",

### Existing table `my_table` is synced without creating other tables
### or affecting pipes' registration.
  • Fixed potential security of public instance tables.
    The API now refuses to sync or serve data if the target is a protected instance table (pipes, users, or plugins).

  • Added not-null check to pipe.get_sync_time().
    The datetime column should never contain null values, but just in case, pipe.get_sync_time() now passes a not-null check to params for the datetime column.

  • Removed prompt for value from pipe.bootstrap().
    The prompt for an optional value column has been removed from the bootstrapping wizard because pipe.columns is now largely used as a collection of indices rather than the original purpose of meta-columns.

  • Pass --debug and other flags in copy pipes.
    Command line flags are now passed to the new pipe when copying an existing pipe.

v1.4.12 โ€“ v1.4.13

  • Fixed an issue when syncing empty DataFrames (#95).
    When syncing an empty list of documents, Pipe.filter_existing() would trigger pulling the entire table into memory. This patch adds a check if the dataframe is empty.

  • Allow the datetime column to be omitted in the bootstrap wizard.
    Now that the datetime index is optional, the bootstrapping wizard allows users to skip this index.

  • Fixed a small issue when syncing to MySQL.
    Due to the addition of MySQL 5.7 support in v1.4.11, a slight edge case arose which broke SQL definitions. This patch fixes MySQL behavior when a WHERE clause is present in the definition.


  • Add support for older versions of MySQL.
    The WITH keyword for CTE blocks was not introduced until MySQL 8.0. This patch uses the older syntax for older versions of MySQL and MariaDB. MySQL 5.7 was added to the test suite.

  • Allow for any iterable in items_str()
    If an iterable other than a list is passed to items_str(), it will convert to a list before building the string:

from meerschaum.utils.misc import items_str
print(items_str({'apples': 1, 'bananas': 2}, quotes=False)
# apples and bananas
  • Fixed an edge case with datetime set to None.
    This patch will ignore the datetime index even if it was set explicitly to None.

  • Added Pipe.children.
    To complement Pipe.parents, setting the parameters key children to a list of pipes' keys will be treated the same as Pipe.parents:

import meerschaum as mrsm
pipe = mrsm.Pipe(
    'a', 'b',
    parameters = {
        'children': [
                'connector': 'a',
                'metric': 'b',
                'location': 'c',
# [Pipe('a', 'b', 'c')]
  • Added support for type:label syntax in mrsm.get_connector().
    The factory function mrsm.get_connector() expects the type and label as two arguments, but this patch allows for passing a single string with both arguments:
import meerschaum as mrsm
# sql:local
  • Fixed more edge case bugs.
    For example, converting to Int64 sometimes breaks with older versions of pandas. This patch adds a workaround.


  • Fixed an issue with syncing background jobs.
    The --name flag of background jobs with colliding with the name keyword argument of SQLConnector.to_sql().

  • Fixed a datetime bounding issue when datetime index is omitted.
    If the minimum datetime value of the incoming dataframe cannot be determined, do not bound the get_data() request.

  • Keep existing parameters when registering plugin pipes.
    When a pipe is registered with a plugin as its connector, the return value of the register() function will be patched with the existing in-memory parameters.

  • Fixed a data type syncing issue.
    In cases where fetched data types do not match the data types in the pipe's table (e.g. automatic datetime columns), a bug has been patched to ensure the correct data types are enforced.

  • Added Venv to the root namespace.
    Now you can access virtual environments directly from mrsm:

import meerschaum as mrsm

with mrsm.Venv('noaa'):
    import pandas as pd


  • Fixed in-place syncs for aggregate queries.
    In-place SQL syncs which use aggregation functions are now handled correctly. This version addresses differences in column types between backtrack and new data. For example, the following query will now be correctly synced:
WITH days_src AS (
  SELECT *, DATE_TRUNC('day', "datetime") AS days
  FROM plugin_stress_test
SELECT days, AVG(val) AS avg_value
FROM days_src
  • Activate virtual environments for custom instance connectors.
    All pipe methods now activate virtual environments for custom instance connectors.

  • Improved database connection performance.
    Cold connections to a SQL database have been sped up by replacing sqlalchemy_utils with handwritten logic (JSON for PostgreSQL-like and SQLite).

  • Fixed an issue with virtual environment verification in a portable environment.
    The portable build has been updated to Python 3.9.15, and this patch includes a check to determine the known site-package path for a virtual environment of None instead of relying on the default user site-packages directory.

  • Fixed some environment warnings when starting the API

v1.4.5 โ€“ v1.4.8

  • Bugfixes and stability improvements.
    These versions included several bugfixes, such as patching --skip-check-existing for in-place syncs and fixing the behavior of --params (build_where()).

v1.4.0 โ€“ v1.4.4

  • Added in-place syncing for SQL pipes.
    This feature is big (enough to warrant a new point release). When pipes with the same instance connector and data source connector are synced, the method sync_pipe_inplace() is invoked. For SQL pipes, this means the entire syncing process will now happen entirely in SQL, which can lead to massive performance improvements.
import meerschaum as mrsm
import pandas as pd

conn = mrsm.get_connector('sql', 'local')
conn.to_sql(pd.DataFrame([{'a': 1}]), 'foo')

pipe = mrsm.Pipe(
    "sql:local", "foo",
    instance = "sql:local",
    parameters = {
        "query": "SELECT * FROM foo"
### This will no longer load table data into memory.

This applies even when the source table's schema changes, just like the dynamic columns feature added in v1.3.0.

To disable this behavior, run the command edit config system and set the value under the keys experimental:inplace_sync to false.

  • Added negation to --params.
    The build_where() function now allows you to negate certain values when prefixed with an underscore (_):
### Show recent data, excluding where `id` equals `2`.
mrsm show data --params id:_2
  • Added --params to SQL pipes' queries.
    Specifying parameters when syncing SQL pipes will add those constraints to the fetch stage.

  • Skip invalid parameters in --params.
    If a column does not exist in a pipe's table, the value will be ignored in --params.

  • Fixed environment issue when starting the Web API with gunicorn.

  • Added an emoji to the SQL Query option of the web console.
  • Fixed an edge case with data type enforcement.
  • Other bugfixes

1.3.x Releases

The 1.3.x series brought a tremendous amount of new features and stability improvements. Read below to see everything that was introduced!


  • Fixed an issue when displaying backtrack data on the Web Console.
    Certain values like pd.NA would break the Recent Data view on the Web Console. Now the values are cast to strings before building the table.

  • Added YAML and JSON support to editing parameters.
    YAML is now the default, and toggle buttons have been added to switch the encoding. Line numbers have also been added to the editors.

  • Removed the index column from the CSV downloader.
    When the download button is clicked, the dataframe's index column will be omitted from the CSV file.

  • Changed the download filename to <target>.csv.
    The download process will now name the CSV file after the table rather than the pipe.

  • Web Console improvements.
    The items in the actions builder now are presented with a monospace font. Actions and subactions will have underscores represented as spaces.

  • Activating the virtual environment None will not override your current working directory.
    This is especially useful when testing the API. Activating the virtual environment None will insert behind your current working directory or '' in sys.path.

  • Added WebSocket Secure Support.
    This has been coming a long time, so I'm proud to announce that the web console can now detect whether the client is connecting via HTTPS and (assuming the server has the appropriate proxy configuration) will connect via WSS.

v1.3.10 โ€“ v1.3.12

  • Fixed virtual environment issues when syncing.
    This one's a doozy. Before this patch, there would frequently be warnings and sometimes exceptions thrown when syncing a lot of pipes with a lot of threads. This kind of race condition can be hard to pin down, so this patch reworks the virtual environment resolution system by keeping track of which threads have activated the environments and refusing to deactivate if other threads still depend on the environment. To enforce this behavior, most manual ivocations of activate_venv() were replaced with the Venv context manager. Finally, the last stage of each action is to clean up any stray virtual environments. Note: You may still run into the wrong version of a package being imported into your plugin if you're syncing a lot of plugins concurrently.

  • Allow custom instance connectors to be selected on the web console.
    Provided all of the appropriate interface methods are implemented, selecting a custom instance connector from the instance dropdown should no longer throw an error.

  • Bugfixes and improvements to the virtual environment system.
    This patch should resolve your virtual environment woes but at a somewhat significant performance penalty. Oh well, 'tis the price we must pay for correct and determinstic code!

  • Fixed custom flags added by add_plugin_argument().
    Refactoring work to decouple plugins from the argument parser had the unintended side effect of skipping over custom flags until after sysargs had already been parsed. This patch ensures all plugins with add_plugin_argument in their root module will be loaded before parsing.

  • Upgraded dash-extensions, dash, and dash-bootstrap-components.
    At long last, dash-extensions will no longer need to be held back.

  • Added additional websockets endpoints.
    The endpoints /ws, /dash/ws/, and /dashws resolve to the same handler. This is to allow compatability with different versions of dash-extensions.

  • Allow for custom arguments to be added from outside plugins.
    The function add_plugin_argument() will now accept arguments when executed from outside a plugin.

  • Fixed verify packages.

v1.3.6 โ€“ v1.3.9

  • Allow for syncing multiple data types per column.
    The highlight of this release is support for syncing multiple data types per column. When different data types are encountered, the underlying column will be converted to TEXT:
import meerschaum as mrsm
pipe = mrsm.Pipe('a', 'b', instance='sql:memory')

pipe.sync([{'a': 1}])
#    a
# 0  1

pipe.sync([{'a': 'foo'}])
#      a
# 0    1
# 1  foo
  • Cleaned up the Web Console.
    The web console's navbar is now more mobile-friendly, and a "sign out" button has been added.

  • Removed plugins import when checking for environment connectors.
    This should make some commands feel more snappy by lazy loading custom connectors.

  • Fixed an issue with an updated versin of uvicorn.
  • Fixed an issue with docker-compose.
  • Fixed an issue with FastAPI on Python 3.7.
  • Added support for Python 3.11.
  • Renamed meerschaum.actions.arguments to meerschaum._internal.arguments.

v1.3.4 โ€“ v1.3.5

  • Define environment connectors with JSON or URIs.
    Connectors defined as environment variables may now have their attributes set as JSON in addition to a URI string.

  • Custom Connectors may now be defined as environment variables.
    You may now set environment variables for custom connectors defined via @make_connector, e.g.:

MRSM_FOO_BAR='{"foo": "bar"}' mrsm show connectors
  • Allow for custom connectors to be instance connectors.
    Add the property IS_INSTANCE = True your custom connector to add it to the official list of instance types:
from meerschaum.connectors import make_connector, Connector

class FooConnector(Connector):
    IS_INSTANCE = True

    def __init__(label: str, **kw):
        super().__init__('foo', label, **kw)
  • Install packages for all plugins with mrsm install required.
    The default behavior for mrsm install required with no plugins named is now to install dependencies for all plugins.

  • Syncing bugfixes.

v1.3.2 โ€“ v1.3.3

  • Fixed a bug with begin and end bounds in Pipe.get_data().
    A safety measure was incorrectly checking if the quoted version of a column was in pipe.get_columns_types(), not the unquoted version. This patch restores functionality for pipe.get_data().
  • Fixed an issue with an upgraded version of SQLAlchemy.
  • Added a parameters editor the Web UI.
    You may now edit your pipes' parameters in the browser through the Web UI!
  • Added a SQL query editor to the Web UI.
    Like the parameters editor, you can edit your pipes' SQL queries in the browser.
  • Added a Sync Documents option to the Web UI.
    You can directly sync documents into pipes on the Web UI.
  • Added the arguments order, limit, begin_add_minutes, and end_add_minutes to Pipe.get_data().
    These new arguments will give you finer control over the data selection behavior.
  • Enforce consistent ordering of indices in Pipe.get_data().
  • Allow syncing JSON-encoded strings.
    This patch allows pipes to sync JSON strings without first needing them to be deserialized.
  • Fixed an environment error with Ubuntu 18.04.
  • Bumped duckdb and duckdb-engine.
  • Added a basic CLI for duckdb.
    This will probably be replaced later down the line.


  • Fixed data type enforcement issues.
    A serious bug in data type enforcement has been patched.
  • Allow Pipe.dtypes to be edited.
    You can now set keys in Pipe.dtypes and persist them with Pipe.edit().
  • Added Pipe.update().
    Pipe.update() is an alias to Pipe.edit(interactive=False).
  • Pipe.delete() no longer deletes local attributes.
    It still removes, but local attributes will now remain intact.
  • Fixed dynamic columns on DuckDB.
    DuckDB does not allow for altering tables when indices are created, so this patch will drop and rebuild indices when tables are altered.
  • Replaced CLOB with NVARCHAR(2000) on Oracle SQL.
    This may require migrating existing pipes to use the new data type.
  • Enforce integers are of type INTEGER on Oracle SQL.
    Lots of data type enforcement has been added for Oracle SQL.
  • Removed datetime warnings when syncing pipes without a datetime column.
  • Removed grabbing the current time for the sync time if a sync time cannot be determined.

v1.3.0: Dynamic Columns


  • Syncing now handles dynamic columns.
    Syncing a pipe with new columns will trigger an ALTER TABLE query to append the columns to your table:

    import meerschaum as mrsm
    pipe = mrsm.Pipe('foo', 'bar', instance='sql:memory')
    pipe.sync([{'a': 1}])
    #    a
    # 0  1
    pipe.sync([{'b': 1}])
    #       a     b
    # 0     1  <NA>
    # 1  <NA>     1

    If you've specified index columns, you can use this feature to fill in NULL values in your table:

    import meerschaum as mrsm
    pipe = mrsm.Pipe(
        'foo', 'bar',
        columns = {'id': 'id_col'},
        instance = 'sql:memory',
    pipe.sync([{'id_col': 1, 'a': 10.0}])
    pipe.sync([{'id_col': 1, 'b': 20.0}])
    #    id_col     a     b
    # 0       1  10.0  20.0
  • Add as many indices as you like.
    In addition to the special index column labels datetime, id, and value, the values of all keys within the Pipe.columns dictionary will be treated as indices when creating and updating tables:

    import meerschaum as mrsm
    indices = {'micro': 'station', 'macro': 'country'}
    pipe = mrsm.Pipe('demo', 'weather', columns=indices, instance='sql:memory')
    docs = [{'station': 1, 'country': 'USA', 'temp_f': 80.6}]
    docs = [{'station': 1, 'country': 'USA', 'temp_c': 27.0}]
    #    station  country  temp_f  temp_c
    # 0        1      USA    80.6    27.0
  • Added a default 60-second timeout for pipe attributes.
    All parameter properties (e.g. Pipe.columns,, Pipe.dtypes, etc.) will sync with the instance every 60 seconds. The in-memory attributes will be patched on top of the database values, so your unsaved state won't be lost (persist your state with Pipe.edit()). You can change the timeout duration with mrsm edit config pipes under the keys attributes:local_cache_timeout_seconds. To disable this caching behavior, set the value to null.

  • Added custom indices and Pandas data types to the Web UI.

Breaking Changes

  • Removed None as default for uninitalized properties for pipes.
    Parameter properties like Pipe.columns, Pipe.parameters, etc. will now always return a dictionary, even if a pipe is not registered.
  • Pipe.get_columns() now sets error to False by default.
    Pipes are now mostly index-agnostic, so these checks are no longer needed. This downgrades errors in several functions to just warnings, e.g. Pipe.get_sync_time().


  • Always quote tables that begin with underscores in Oracle.
  • Always refresh the metadata when grabbing sqlalchemy tables for pipes to account for dynamic state.

1.2.x Releases

This series brought many industry-ready features, such as the @make_connector decorator, improvements to the virtual environment system, the environment variable MRSM_PLUGINS_DIR, and much more.


  • Added support for Windows junctions for virtual environments.
    This included many changes to fix functionality on Windows. For example, the addition of the MRSM_PLUGINS_DIR environment variable broke Meerschaum on Windows, because Windows requires administrator rights to create symlinks.


  • Custom connectors may now have register(pipe) methods.
    Just like the module-level register(pipe) plugin function, custom connectors may also provide this function as a class member.
  • Print a traceback if fetch(pipe) breaks.
    A more verbose traceback is printed if a plugin breaks during the syncing process.
  • Cleaned up sync pipes output.
    This patch cleans up the syncing process's pretty output.
  • Respect --nopretty in sync pipes.
    This flag will only print JSON-encoded dictionaries for sync pipes. Tracebacks may still interfere without standard output, however.

v1.2.5 โ€“ v1.2.7

  • Venv context managers do not deactivate previously activated venvs.
    You can safely use Venv without worrying about deactivating your previously activated environments.
  • Better handling of nested plugin dependencies.
  • Plugin.get_dependencies() will not trigger an import.
    If you want certainty about a plugin's required list, trigger an import manually. Otherwise, it will use ast.literal_eval() to determine the required list from the source itself. This only works for statically set required lists.
  • Provide rich traceback for broken plugins.
    If a plugin fails to import, a nice traceback is printed out in addition to a warning.
  • Only cache Pipe.dtypes if the pipe exists.
  • Pass current environment to subprocesses.
    This should retain any custom configuration you've set in the main process.
  • Hard-code port 5432 as the target DB container port in the stack.
    Changing the host port now will not change the target port in the container.
  • Fixed a bug with background jobs and to_sql().
    The --name flag was conflicting with to_sql().
  • Reimplemented apply_patch_to_config().
    This patch removes cascadict as a vendored dependency and replaces it with a simpler implementation.
  • Removed network request for shell connectivity status.
    The shell now simply checks for the existence of the connector. This may occasionally print an inaccurate connection status, but the speed benefit is worth it.
  • Moved dill and other required dependencies into the sql dependency group.
  • Replaced redengine with rocketry.
  • Patched Literal into typing for Python 3.7.
  • Fixed shell commands.
    This includes falling back to ' '.join instead of shlex.join for Python 3.7.

v1.2.1 โ€“ v1.2.4

  • Added the @make_connector decorator.
    Plugins may now extend the base Connector class to provide custom connectors. For most cases, the built-in plugin connector should work fine. This addition opens up the internal connector system so that plugin authors may now add new types. See below for a minimal example of a new connector class:
# ~/.config/meerschaum/plugins/

from meerschaum.connectors import make_connector, Connector

REQUIRED_ATTRIBUTES = {'username', 'password'}

class FooConnector(Connector):

    def __init__(self, label: str, **kw):
        Instantiate the base class and verify the required attributes are present.
        kw['label'] = label
        super().__init__('foo', **kw)

    def fetch(self, pipe, **kw):
        Return a dataframe (or list of dicts / dict of lists).
        The same as you would in a regular fetch plugin, except that now
        we can store configuration within the connector itself.
        return [{self.username: '2020-01-01'}]
  • Allow for omitting datetime column index.
    The datetime column name is still highly recommended, but recent changes have allowed pipes to be synced without a dedicated datetime axis. Plenty of warnings will be thrown if you sync your pipes without specifying a datetime index. If a datetime column can be found, it will be used as the index.
import meerschaum as mrsm
### This will work but throw warnings.
mrsm.Pipe('foo', 'bar').sync([{'a': 1}])



  • Added the action start connectors.
    This command allows you to wait until all of the specified connectors are available and accepting connections. This feature is very handy when paired with the new MRSM_SQL_X URI environment variables.

    This one's been on my to-do list for quite a bit! You can now place your plugins in a dedicated, version-controlled directory outside of your root directory.

Like MRSM_ROOT_DIR, specify a path with the environment variable MRSM_PLUGINS_DIR:

  mrsm show plugins
  • Allow for symlinking in URI environment variables.
    You may now reference configuration keys within URI variables:
  • Increased token expiration window to 12 hours.
    This should reduce the number of login requests needed.

  • Improved virtual environment verification.
    More edge cases have been addressed.

  • Symlink Meerschaum into Plugin virtual environments.
    If plugins do not specify Meerschaum in the required list, Meerschaum will be symlinked to the currently running package.

Breaking changes

  • API endpoints for registering and editing users changed.
    To comply with OAuth2 convention, the API endpoint for registering a user is now a url-encoded form submission to /users/register (/user/edit for editing).

    You must upgrade both the server and client to v1.2.0+ to login to your API instances.

  • Replaced meerschaum.utils.sql.update_query() with meerschaum.utils.sql.get_update_queries().
    The new function returns a list of query strings rather than a single query. These queries are executed within a single transaction.


  • Removed version enforcement in pip_install().
    This changed behavior allows for custom version constraints to be specified in Meerschaum plugins.

  • Backported UPDATE FROM query for older versions of SQLite.
    The current mutable data logic uses an UPDATE FROM query, but this syntax is only present in versions of SQLite greater than 3.33.0 (released 2020-08-14). This releases splits the same logic into DELETE and INSERT queries for older versions of SQLite.

  • Fixed missing suggestions for shell-only commands.
    Completions for commands like instance are now suggested.

  • Fixed an issue with killing background jobs.
    The signals were not being sent correctly, so this release includes better job process management.

1.1.x Releases

The 1.1.x series brought a lot of great new features, notably connector URI parsing (e.g. MRSM_SQL_<LABEL>), parsing underscores as spaces in actions, and rewriting the Docker image to run at as a normal user.

v1.1.9 โ€“ v1.1.10

  • Fixed plugins virtual environments.
    A typo in v1.1.8 temporarily broke plugins, and this patch fixes that change.
  • Fixed Meerschaum on Windows.
    A change in a previous release allowed for dist-packages for the root user (not advised but supported). The check for root (os.geteuid()) does not exist on Windows, so this patch accounts for that behavior.
  • Tweaked screen clearing on Windows.
    Meerschaum now always uses clear or cls on Windows instead of ANSI escape sequences.

v1.1.5 โ€“ v1.1.8

  • Fixed MRSM_PATCH behavior.
    In the docker image, MRSM_PATCH is used to overwrite host for sql:main. This patch restores that behavior (with a performance boost).
  • Fixed virtual environment verification.
    This patch prevents circular symlinks.
  • Fixed manually_import_module().
    Previous refactoring efforts had broken manually_import_module().
  • Refactoring
    While trying to implement multi-thread configuration patching (discarded for the time being), much of the configuration system was cleaned up.

v1.1.1 โ€“ v1.1.4


The first four versions following the initial v1.1.0 release addressed breaking changes and edge cases. Below are some notable issues resolved:

  • Fixed broken Docker images.
    Changes to the environment and package systems broke functionality of the Docker images. For example, v1.1.0 switched to a stricter package management policy, but this new policy broke the mechanism behind the Docker images (user-level vs venv-level packages).
  • Verify virtual environments for multiple Python versions.
    When a virtual environment is first activated, Meerschaum now verifies that the python symlinks point to the correct versions. This is necessary due to a quirk in venv and virtualenv where activating an existing environment with a different Python version overwrites the existing python symlink. It also ensures that the symlinks specify the correct version number, e.g. python3.10. This bevavior is now automatic but may be invoked with mrsm verify venvs.
  • Fixed inconsistent environment behavior with gunicorn.
    This one was tricky to troubleshoot. Due to the migration to the user-level Docker image, a subtle bug surfaced where the environment variables for gunicorn were incorrectly serialized.
  • Fixed slow-performing edge cases in determine_version().
    Inconsistencies in naming conventions in some packages like pygments led to failures to quickly determine the version.
  • Fixed Web API actions.
    In v1.1.0, the default virtual environment was pinned to mrsm, and this broke a function which relied on the old inferred default value of None. Always remember: explicit is better than implicit.
  • Fixed start job for existing jobs.
    The same naming change broke daemon_action(). Explcit code is important, folks!


What's New

  • Underscores in actions may now be parsed as spaces.
    This took way more work than expected, but anyway, custom actions with underscores in the function names are now treated as spaces! Consider the following:
def foo_bar(**kw):
    return True, "Huzzah!"

The above action may now be executed as foo bar or foo_bar:

mrsm foo bar
  • Create a SQLConnector or APIConnector directly from a URI.
    If you already have a connection string, you can skip providing credentials and build a connector directly from the URI. If you omit a label, then the lowercase form of '<username>@<host>/<database>' is used:
from meerschaum.connectors import SQLConnector
uri = 'postgresql://user:pass@localhost:5432/db'

conn = SQLConnector(uri=uri)
# sql:user@localhost/db

conn = SQLConnector('foo', uri=uri)
# sql:foo

conn = SQLConnector.from_uri(uri)
# sql:user@localhost/db

The APIConnector may also be built from a URI:

from meerschaum.connectors import APIConnector
uri = 'http://user:pass@localhost:8000'

conn = APIConnector(uri=uri)
# api:username@localhost

conn = APIConnector('bar', uri=uri)
# api:bar

conn = APIConnector.from_uri(uri)
# api:user@localhost
  • Define temporary connectors from URIs in environment variables.
    If you set environment variables with the format MRSM_SQL_<LABEL> to valid URIs, new connectors will be available under the keys sql:<label>, where <label> is the lowercase form of <LABEL>:
export MRSM_SQL_FOO=sqlite://///path/to/sqlite.db
mrsm show connectors sql:foo

You can set as many connectors as you like, and they're treated the same as connectors registered in your permanent configuration.

### The following environment variable was already exported:
### MRSM_SQL_FOO=sqlite://///path/to/sqlite.db

import meerschaum as mrsm
conn = mrsm.get_connector('sql', 'foo')
# /path/to/sqlite.db


  • Resolved issues with conflicting virtual and base environments.
  • Only reinstall a package available at the user-level if its version doesn't match.
    This was a subtle bug, but now packages are handled strictly in virtual environments except when an appropriate version is available. This may slow down performance, but the change is necessary to ensure a consistent environment.

Potentially Breaking Changes

  • The database file path for SQLite and DuckDB is now required.
    When creating a SQLConnector with the flavors sqlite or duckdb, the attribute database (a file path or :memory:) is now required.
  • Removed --config and --root-dir.
    These flags were added very early on but have always caused issues. Instead, please use the environment variables MRSM_CONFIG or MRSM_PATCH for modifying the runtime configuration, and use MRSM_ROOT_DIR to specify a file path to the root Meerschaum directory.
  • Virtual environments must be None for standard library packages.
    When importing a built-in module with attempt_import(), specify venv=None to avoid attempting installation.
  • The Docker image now runs as meerschaum instead of root.
    For improved security, the docker image now runs at a lower privilege.

1.0.x Releases

The v1.0.0 release was big news. A ton of features, bugfixes, and perfomance improvements were introduced: for example, v1.0.0 brought support for mutable pipes and data type enforcement. Later releases in the v1.0.x series included --schedule, the Venv context manager, and a whole lot of environment bugfixes.


  • Plugins may now have requirements.txt.
    If a plugin contains a file named requirements.txt, the file will be parsed alongside the packages specified in the required list.
  • Added the module meerschaum.utils.venv.
    Functions related to virtual environment management have been migrated from meerschaum.utils.packages to meerschaum.utils.venv.
  • Added the Venv class.
    You can now manage your virtual environments with the Venv context manager:
from meerschaum.utils.venv import Venv

with Venv():
    import pandas

with Venv('foo'):
    import bar

You can also activate the environments for a Plugin:

from meerschaum.utils.venv import Venv
from meerschaum.plugins import Plugin

with Venv(Plugin('noaa')):
    import requests
  • Removed --isolated from pip_install.
    Virtual environments will now respect environment variables and your global pip configuration (~/.pip/pip.conf).
  • Fixed issues for Python 3.7

v1.0.3 โ€” v1.0.5

  • Fixed environment bugs.
    This patch resolves issues with the environment variables MRSM_ROOT_DIR, MRSM_CONFIG, and MRSM_PATCH as well as the configuration directories patch_config and permanent_patch_config.
  • Fixed package management system.
    Meerschaum better handles package metadata, resolving some annoying issues. See meerschaum.utils.packages.get_module_path() for an example of the improved virtual environment management system. Also, wheel is automatically installed when new packages are installed into new virtual environments.
  • Set the default venv to 'mrsm'.
    In all functions declared in meerschaum.utils.packages, the default value of venv is always 'mrsm'. Use None for the venv to use the user's site packages.
  • Updated dependencies.
  • Added python-dotenv as a dependency.
  • Fixed a catalog issue with duckdb.
  • Updated the testing suite.
  • More refactoring.
    Code needs to be beautiful!


  • Allow id column to be omitted.
    When generating the UPDATE query, the id column may now be omitted (NOTE: the datetime column will be assumed to be the primary key in this scenario).
  • Added --schedule (-s or --cron).
    The --schedule flag (-s) now lets you schedule any command to be executed regulary, not unlike crontab. This can come in handy with --daemon (-d), e.g.:
mrsm sync pipes -c plugin:foo -s hourly -d

Here is more information on the scheduling syntax.

  • Fixed an issue with SQLite.
    An issue where the value columns not loading in SQLite has been addressed.


  • Added citus as an official database flavor.
    Citus is a distributed database built on PostgreSQL. When an id column is provided, Meerschaum will call create_distributed_table() on the pipe's ID index. Citus has also been added to the official test suite.
  • Changed end datetimes to be exclusive.
    The end parameter now generates < instead of <=. This shouldn't be a major breaking change but is important to be aware of.
  • Bumped rich to v12.4.4.

v1.0.0: Mutable at Last

What's New

  • Inserts and Updates
    An additional layer of processing separates new rows from updated rows. Meerschaum uses your datetime and id columns (if you specified an id column) to determine which rows have changed. Therefore a primary key is not required, as long as the datetime column is unique or the datetime and id columns together emulate a composite primary key.

    Meerschaum will insert new rows as before as well as creating a temporary table (same name as the pipe's target but with a leading underscore). The syncing engine then issues the appropriate MERGE or UPDATE query to update all of the rows in a batch.

    For example, the following lines of code will result in a table with only 1 row:

    >>> import meerschaum as mrsm
    >>> pipe = mrsm.Pipe('foo', 'bar', columns={'datetime': 'dt', 'id': 'id'})
    >>> ### Insert the first row.
    >>> pipe.sync([{'dt': '2022-06-26', 'id': 1, 'value': 10}])
    >>> ### Duplicate row, no change.
    >>> pipe.sync([{'dt': '2022-06-26', 'id': 1, 'value': 10}])
    >>> ### Update the value columns of the first row.
    >>> pipe.sync([{'dt': '2022-06-26', 'id': 1, 'value': 100}])
  • Data Type Enforcement.
    Incoming DataFrames will be cast to the pipe's existing data types, and if you want total control, you can manually specify the Pandas data types for as many columns as you like under the dtypes key of Pipe.parameters, e.g.:

      datetime: timestamp_utc
      id: station_id
      timestamp_utc: 'datetime64[ns]'
      station_id: 'Int64'
      station_name: 'object'

  • Allow for NULL in INT columns.
    Before pandas v1.3.0, including a null value in an int column would cast it to a float. Now pd.NA has been added and is leveraged in Meerschaum's data type inference system.
  • Plugins respect .gitignore
    When publishing a plugin that is contained in a git repository, Meerschaum will parse your .gitignore file to determine which files to omit.
  • Private API Mode.
    Require authentication on all API endpoints with start api --private.
  • No Authentication API Mode.
    Adding --no-auth will disable all authentication on all API endpoints, including the web console.


  • Plugin packaging
    A breaking bug in the process of packaging and publishing Meerschaum plugins has been patched.

  • Correct object names in Oracle SQL.
    Oracle has finally been brought up to speed with other flavors.

  • Multi-module plugins fix.
    A small but important fix for multi-module plugins has been applied for their virtual environments.
  • Improved virtual environment handling for Debian systems.
    If venv is not available, Meerschaum now better handles falling back to virtualenv.
  • Allow for syncing lists of dicts.
    In addition to syncing a dict of lists, Pipe.sync() now supports a list of dicts.
  • Allow for begin to equal None for Pipe.fetch().
    The behavior of determining begin from Pipe.get_sync_time() only takes place when begin is omitted, not when it is None. Now begin=None will not add a lower bound to the query.

0.6.x Releases

The 0.6.x series brought a lot of polish to the package, namely through refactoring and changing some legacy features to a meet expected behaviors.

v0.6.3 โ€“ v0.6.4: Durable Venvs

  • Improved durability of the virtual environments.
    The function meerschaum.utils.packages.manually_import_module() behaves as expected, allowing you to import different versions of modules. More work needs to be done to see if reintroducing import hooks would be beneficial.
  • Activate plugin virtual environments for API plugins.
    If a plugin uses the @api_plugin decorator, its virtual environment will be activated before starting the API server. This could potentially cause problems if you have many API plugins with conflicting dependencies, but this could be mitigated by isolating environments with MRSM_ROOT_DIR.
  • Changed name to import_name for determine_version().
    The first argument in meerschaum.utils.packages.determine_version() has been renamed from name to the less-ambiguous import_name.
  • Shortened the IDs for API environments.
    Rather than a long UUID, each instance of the API server will have a randomly generated ID of six letters. Keep in mind it is randomly generated, so please excuse any randomly generated words.
  • Removed version enforcement for uvicorn and gunicorn.
    Uvicorn has a lot of hidden imports, and using our home-brewed import system breaks things. Instead, we now use the default attempt_import behavior of check_update=False.
  • Reintroduced verify packages to
    Upgrading Meerschaum will check if the virtual environment packages satisfy their required versions.
  • Moved pkg_resources patch from the module-level.
    In v0.6.3, the monkey-patching for flask-compress happened at the module level, but this was quickly moved to a lazy patch in v0.6.4.
  • Bugfixes
    Versions 0.6.3 and 0.6.4 were yanked due to some unforeseen broken features.
  • Bumped several dependencies.

v0.6.0 โ€“ v0.6.2: Robust Plugins and Beautiful Pipes

Potentially Breaking Changes

  • Renamed to meerschaum.utils.sql.
    A dummy module was created at the old import path, but this will be removed in future releases.
  • Migrated to meerschaum.core.
    Important class definitions (e.g. User) have been migrated from meerschaum._internal to meerschaum.core. You can still import meerschaum.core.Pipe as mrsm.Pipe, however.
  • Moved to
    Finally marked it off the to-do list!
  • Pipe.__str__() and Pipe.__repr__() now return stylized strings.
    This should make reading logs significantly more pleasant. You can add syntax highlighting back to strings containing Pipe() with meerschaum.utils.formatting.highlight_pipes().

New Features

  • Plugins
    Exposed the meerschaum.Plugin class, which will make cross-pollinating between plugins simpler.
  • Uninstall procedure
    Plugins now ship with a proper uninstall() method.
  • Sharing dependencies
    Plugins may now import dependencies from a required plugin's virtual environment. E.g. if plugin foo requires plugin:bar, and bar requires pandas, then foo will be able to import pandas.
  • Allow other repos for required plugins.
    You can now specify the keys of a required plugin's repo following @, e.g. foo may require plugin:bar@api:main.
  • Isolate package cache.
    Each virtual environment now uses an isolated cache folder.
  • Handle multiple versions of packages in determine_version()
    When verifying packages, if multiple dist-info directories are found in a virtual environment, import the package in a subprocess to determine its __version__.
  • Specify a target table. (Pipe.parameters['target']) now governs the name of the underlying SQL table.


  • Circular dependency resolver
    Multiple plugins may now depend on each other without entering a recursive loop.
  • Held back dash_extensions due to breaking API changes.
    Future releases will migrate to dash_extensions>1.0.0.
  • Fixed meerschaum.plugins.add_plugin_argument().
    Refactoring broke something awhile back; more plugins-focused tests are needed.
  • Fixed an issue with fontawesome and mkdocs-material.
  • Fixed pickling issue with mrsm.Pipe.


  • pdoc changes.
    Added __pdoc__ and __all__ to public modules to simplify the package docs.
  • Lots of cleanup.
    Almost all of the docstrings have been edited.

0.5.x Releases

The 0.5.x series tied up many loose ends and brought in new features, such as fulling integrating Oracle SQL, rewriting most of the doctrings, and adding tags and key negation. It also added the clear pipes command and introduced the GUI and webterm.

v0.5.14 โ€“ v0.5.15

  • Added tags.
    Pipes may be grouped together pipes. Check the docs for more information.
  • Tags may be negated.
    Like the key negation added in v0.5.13, you can choose to ignore tags by prefacing them with _.
  • Bugfixes for DuckDB
  • Updated documentation.
  • Fixed issue with flask-compress.
    When starting the API for the first time, missing flask-compress will not crash the server.


  • Key negation when selecting pipes.
    Prefix connector, metric, or location with _ to select pipes that do NOT have that key.
  • Added the setup plugins command.
    Run the command setup plugins followed by a list of plugins to execute their setup() functions.
  • Renamed pipes' keys methods function.
    The function meerschaum.utils.get_pipes.methods() is renamed to meerschaum.utils.get_pipes.fetch_pipes_keys().
  • Improved stability for DuckDB.
  • Bumped dependencies.
    DuckDB, FastAPI, and Uvicorn have been updated to their latest stable versions.

v0.5.11 โ€” v0.5.12

  • Improved Oracle support.
    Oracle SQL has been fully integrated into the testing suite, and critical bugs have been addressed.
  • Added the install required command.
    When developing plugins, run the command install required to install the packages in the plugin's required list into its virtual environment.
  • Migrated docstrings.
    To improve legibility, many docstrings have been rewritten from reST- to numpy-style. This will make browsing easier.


  • Added the clear pipes command.
    Users may now delete specific rows within a pipe using pipe.clear(). This new method includes support for the --begin, --end, and --params flags.
  • Changed the default behavior of --begin.
    The --begin flag is now only included when the user specifies and no longer defaults to the sync time.
  • Added --timeout-seconds.
    The flags --timeout-seconds and --timeout make the syncing engine sync each pipe in a separate subprocess and will kill the process if the sync exceeds the number of provided seconds.
  • Fixed shell argparse bug.
    When editing command line arguments within the shell, edge cases no longer cause the shell to exit.

v0.5.6 โ€” v0.5.9

  • Added support for gunicorn.
    Gunicorn may be used to manage API processes with the --production or --gunicorn flags. The --production flag is now default in the Docker image of the API server.
  • Updated bootstrap pipes flow.
    The interactive bootstrapping wizard now makes use of the new register() plugins API as well as asking for the value column.
  • Fixed edge cases in Pipe.filter_existing().
    Better enforcement of NaT as well as --begin and --end now reduces edge-case bugs and unexpected behavior.
  • Re-introduced the full Docker image.
    Inclusion of the start gui command led to the full version of the Docker image requiring GTK and dependencies. Now you can forward the GUI with docker run -e DISPLAY -v /tmp/.X11-unix:/tmp/.X11-unix bmeares/meerschaum:full start gui
  • Added to the root directory.
    Only dynamic dependencies with BSD, LGPL, MIT, and Apache licenses remain.
  • Fixed plugin installation bug (again).
  • Allow for plugins with hyphens in the name.
  • Lots of refactoring and tiny bugfixes.

v0.5.3 โ€“ v0.5.5

  • Refactored the start gui and start webterm commands.
    The start gui command opens a window which displays the webterm. This terminal will be integrated into the dashboard later.
  • Began work on the desktop build.
    Work on building with PyOxidizer began on these releases.

v0.5.1 โ€“ v0.5.2

  • Added the experimental commands start gui and start webterm.
    The desktop GUI will be rewritten in the future, but for now it starts a webview for the web console. The webterm is an instance of xterm (not xterm.js, having issues) and will eventually replace the current web console "terminal" output. The desktop GUI will also be replaced and will include the webterm once I can get it working on Windows.
  • Isolated API processes.
    Meerschaum API workers refer to the environment variable MRSM_SERVER_ID to determine the location of the configuration file. This results in the ability to run multiple instances of the API concurrently (at last)!
  • Fixed plugin installation bug.
    When installing plugins, the expected behavior of checking if it's already installed occurs.
  • Replaced semver.match() with semver.VersionInfo.match().
    This change resolves depreciation warnings when building the package.
  • Added the /info endpoint to the API.
    This allows users to scrape tidbits of information about instances. The current dictionary returns the version and numbers of pipes, plugins, and users. More information will be added to this endpoint in future releases.


  • New syncing engine.
    The sync pipes command reduces concurrency issues while nearly halving syncing times for large batches of pipes.
  • Syncing progress bar.
    The sync pipes command displays a progress bar (only in the shell) to track the number of completed pipes.
  • Bumped default TimescaleDB image to PostgreSQL 14.
    You can continue using PostgreSQL 13 if you already have an existing database.
  • Changed API endpoints.
    An endpoint for deleting pipes was added, and the editing and registration endpoints were changed to match the connector, metric, location path scheme.
  • Redesigned test suite.
    The pytest environment now checks syncing, registration, deletion, etc. for pipes and users with many database flavors.
  • Cleanup and small bugfixes.
    As a result of the updated testing suite, issues with several database flavors as well as the API have been resolved.

0.4.x Releases

The 0.4.x series dramatically updated Meerschaum, such as ensuring compatibility with Python 3.10, migrating to Bootstrap 5, and implementing useful features like the redesigned web console and the shell toolbar.

v0.4.16 โ€” v0.4.18

  • Rewritten API `register()` methods.
  • MySQL / MariaDB and CockroachDB fixes.
  • Additional tests.

v0.4.11 โ€” v0.4.15

  • Change the number of columns when printing items.
    Depending on the lengths of items and size of the terminal, the number of columns is reduced until most items are not truncated.
  • Allow shell jobs with the -f flag.
    In addition to --allow-shell-job, the --force flag permits non-Meerschaum commands to be run. If these flags are absent, a more informative error message is printed.
  • Redesigned the bottom toolbar.
    The bottom toolbar now uses a black background with white text. Although this technically still prints ANSI when the global ANSI configuration is false, it still does toggle color.
  • More bugfixes.
    A warning when installing plugins has been addressed, and other virtual environment and portable bugs have been fixed.

v0.4.8 โ€” v0.4.10

  • Added the bottom toolbar to the interactive shell.
    The includes the current instance, repo, and connection status.
  • Fixed parsing issue with the Docker build.
    There is a strange edge case where multiple levels of JSON-encoding needed to be escaped, and this scenario has been accounted for.
  • Enforce MRSM_CONFIG and MRSM_PATCH in the Web Console actions.
    The Docker version of the API uses environment variables to manage instances, so this information is passed along to children threads.
  • Delayed imports when changing instances.
    This postpones trying to connect to an instance until as late as possible.

v0.4.1 โ€” v0.4.7

  • Added features to the Web Console.
    Features such as the Show Pipes button and others were added to give the Web Console better functionality.
  • Migrated the Web Console to Bootstrap 5.
    Many components needed to be modified or rewritten, but ultimately the move to Bootstrap 5 is worth it in the long run.
  • Updated to work on Python 3.10.
    This included creating a standalone internal module for cascadict since the original project is no longer maintained.
  • Tighter security.
    Better enforcement of datetimes in dateadd_str() and denying users access to actions if the permissions setting does not allow non-admins to perform actions.
  • Bugfixes for broken dependencies.
    In addition to migrating to Bootstrap 5, components like PyYAML and fastapi-login changed their function signatures which broke things.


  • Allow for other plugins to be specified as dependencies.
    Other plugins from the same repository may be specified in the required list.
  • Added warnings for broken plugins.
    When plugins fail to be imported, warnings are thrown to help authors identify the problem.
  • Added registration to the Web Console.
    New users may create accounts by clicking the No account? link on the login page.
  • Added the verify action.
    For now, verify packages ensures that the installed dependencies meet the stated requirements for the installed version of Meerschaum.
  • Fixed "ghost" background jobs.
    Ensure that jobs are actually running before marking them as so.

0.3.x Releases

Version 0.3.0 introduced the web interface and added more robust SQL support for various flavors, including MSSQL and DuckDB.

v0.3.12 โ€” v0.3.19

  • Mostly small bugfixes.
    Docker-compose fixes, params in get_pipe_rowcount(), unique index names for pipes.
  • Added newest flag to pipe.get_sync_time().
    Setting newest=False will return the oldest time instead of the newest.
  • Migrated filter_existing to a member of Pipe.
    Although the current implementation for APIConnectors offloads filtering to the SQLConnector, soon filtering will take place locally to save bandwidth.
  • Updated Docker base image.
    Bumped base image from Python 3.7 on Debian Buster Slim to Python 3.9 on Debian Bullseye Slim. Also removed ARM images for the sake of passing builds and reducing build times (e.g. DuckDB fails to compile with QEMU).
  • Improved DuckDB support.
    sql:memory is now the default in-memory DuckDB instance.

v0.3.1 โ€“ v0.3.11

  • Improved Microsoft SQL Server support.
  • Added plugins page to the dashboard.
    Although somewhat hidden away, the path /dash/plugins will show the plugins hosted on the API repository. If the user is logged in, the descriptions of plugins belonging to that user become editable.
  • Added locks to resolve race conditions with threading.
  • Added --params when searching for data and backtracked data.
  • Fixed the --params flag for API pipes.
  • Added experimental multiplexed fetching feature
    To enable this feature, run mrsm edit config system and under the experimental section, set fetch to true.
  • Bugfixes and stability improvements


  • Introduced the Web Interface.
    Added the Meerschaum Web Interface, an interactive dashboard for managing Meerschaum instances. Although not a total replacement for the Meerschaum Shell, the Web Interface allows multiple users to share connectors without needing to remote into the same machine.

  • Background jobs
    Actions may be run in the background with the -d or --daemon flags or with the action start job. To assign a name to a job, pass the flag --name.

  • Added duckdb as a database flavor
    The duckdb database flavor is a single file, similar to sqlite. Future releases may use duckdb as the cache store for local pipes' data.

  • Added uninstall plugins and uninstall packages.
    Plugins and virtual environment pip packages may now be removed via the uninstall command.

  • Delete plugin from repository
    The command delete plugins now deletes the archive file and database registration of the plugin on the remote repository. This does not uninstall plugins, so deleted plugins may be re-registered if they are still installed on the client.

  • Bound syncing with --begin and --end
    When performing a sync, you can specify --begin and --end to bound the search for retrieving data.

  • Bugfixes and improvements
    Small bugfixes like including the location None with other locations and improvements like only searching for plugin auto-complete suggestions when the search term is at least 1 character long.

0.2.x Releases

Version 0.2 improved greatly on 0.1, with a greater focus on the user experience, plugins, local performance, and a whole lot more. Read the release notes below for some of the highlights.


  • Critical bugfixes. Version 0.2.22 fixes some critical bugs that went unnoticed in v0.2.21 and is another backport from the 0.3.x branch.


  • Bugfixes and performance improvements. Improvements that were added to v0.3.0 release candidates were backported to the 0.2.x series prior to the release of v0.3.0. This release is essentially v0.3.0 with the Web Interface disabled.


  • Reformatted show columns to tables.
    The action show columns now displays tables rather than dictionaries.
  • SQLConnector bugfixes.
    The debug flag was breaking functionality of SQLConnector objects, but now connectors are more robust and thread safe.
  • Added instance as an alias to mrsm_instance when creating Pipe objects.
    For convenience, when building Pipes, instance may be used in place of mrsm_instance.


  • Added show columns action.
    The action show columns will now display a pipe's columns and data types.
  • docker-compose bugfix.
    When docker-compose is installed globally, skip using the virtual environment version.
  • Refactoring / linting
    A lot of code was cleaned up to conform with cleaner programming practices.


  • Added login action.
    To verify or correct login credentials for API instance, run the login action. The action will try to log in with your defined usernames and passwords, and if a connector is missing a username or password is incorrect, it will ask if you would like to try different login credentials, and upon success, it will ask if you would like to save the new credentials to the primary configuration file.

  • Critical bugfix.
    Fixed bug where default values were being copied over from the active shell instance. I finally found, deep in the code, the missing .copy().

  • Reset api:mrsm to default repository.
    In my task to move everything to the preconfigured instance, I overstepped and made the default repository into the configured instance, which by default is a SQLConnector, so that broke things! In case you were affected by this change, you can simply reset the value of default_repository to api:mrsm (or your api server) to return to the desired behavior.

  • ๐Ÿงน Housekeeping (refactoring).
    I removed nearly all instances of declaring mutable types as optional values, as well as additional typing hints. There may still be some additional cleaning to do, but now the functions are neat and tidy!


  • Added CockroachDB as a supported database flavor.
    CockroachDB may be a data source or a Meerschaum backend. There may be some performance tuning to do, but for now, it is functional. For example, I may implement bulk insert for CockroachDB like what is done for PostgreSQL and TimescaleDB.
  • Only attempt to install readline once in Meerschaum portable.
    The first Meerschaum portable launch will attempt to install readline, but even in case of failure, it won't try to reinstall during subsequent launches or reloads.
  • Refactored SQLAlchemy configuration.
    Under system:connectors:sql, the key create_engine has been added to house all the sqlalchemy configuration settings. WARNING: You might need to run delete config system to refresh this portion of the config file in case any old settings break things.
  • Dependency conflict resolution.
  • As always, more bugfixes :)


  • Hypertable improvements and bugfixes.
    When syncing a new pipe, if an id column is specified, create partitions for the number of unique id values.
  • Only use api:mrsm for plugins, resort to default instance for everything else.
  • Fix bug that mirrored changes to main under default.


  • MySQL/MariaDB bugfixes.
  • Added aiomysql as a driver dependency.


  • Implemented bootstrap pipes action.
    The bootstrap pipes wizard helps guide new users through creating connectors and pipes.
  • Added edit pipes definition action.
    Adding the word definition to the edit pipes command will now open a .sql file for pipes with sql connectors.
  • Changed api_instance to symlink to instance by default.
  • Registering users applies to instances, not repositories.
    The action register users now uses the value of instance instead of default_repository. For users to make accounts with, they will have to specify -i api:mrsm.


  • Fixed symlink handling for nesting dictionaries.
    For example, the environment variables for the API service now contain clean references to the meerschaum and system keys.
  • Added MRSM_PATCH environment variable.
    The MRSM_PATCH environment variable is treated the same as MRSM_CONFIG and is loaded after MRSM_CONFIG but before patch or permanent patch files. This allows the user to apply a patch on top of a symlinked reference. In the docker-compose configuration, MRSM_PATCH is used to change the sql:main hostname to db, and the entire meerschaum config file is loaded from MRSM_CONFIG.
  • Bugfixes, improved robustness.
    Per usual, many teeny bugs were squashed.


  • Improved symlink handling in the configuration dictionary.
    Symlinks are now stable and persistent but at this time cannot be chained together.
  • Improved config file syncing.
    Generated config files (e.g. Grafana data sources) may only be edited from the main edit config process.
  • Upgraded to PostgreSQL 13 TimescaleDB by default.
    This may break existing installs, but you can revert back to 12 with edit config stack and changing the string latest-pg13-oss under the db image to latest-pg12-oss.
  • Bugfixes.
    Like always, this release includes miscellaneous bugfixes.

v0.2.11 (release notes before this point are back-logged)

  • API Chaining
    Set a Meerschaum API as a the parent source connector for a child Meerschaum API, as if it were a SQLConnector.


  • MRSM_CONFIG critical bugfix
    The environment variable MRSM_CONFIG is patched on top of your existing configuration. MRSM_PATH is also a patch that is added after MRSM_CONFIG.


  • API and SQL Chunking
    Syncing data via an APIConnector or SQLConnector uploads the dictionary or DataFrame in chunks (defaults to a chunksize of 900). When calling read() with a SQLConnector, a chunk_hook callable may be passed, and if as_chunks is True, a list of DataFrames will be returned. If as_iterator is True, a dataframe iterator will be returned.


  • API Chaining introduction
    Chaining is first released on v0.2.8, though it is finalized in 0.2.11.


  • Shell autocomplete bugfixes


  • Miscellaneous bugfixes and dependency updates

v0.2.1 โ€” v0.2.5

  • Shell improvements
    Stability, autosuggest, and more.
  • Virtual environments
    Isolate dependencies via virtual environments. The primary entrypoint for virtual environments is meerschaum.utils.packages.attempt_import().


  • Plugins
    Introduced the plugin system, which allows users and developers to easily integrate any data source into Meerschaum. You can read more about plugins here.
  • Repositories
    Repositories are Meerschaum APIs that register and serve plugins. To register a plugin, you need a user login for that API instance.
  • Users
    A user account is required for most functions of the Meerschaum API (for security reasons). By default, user registration is disabled from the API side (but can be enabled with edit config system under permissions). You can register users on a direct SQL connection to a Meerschaum instance.
  • Updated shell design
    Added a new prompt, intro, and more shell design improvements.
  • SQLite improvements
    The connector sql:local may be used as as backend for cases such as when running on a low-powered device like a Raspberry Pi.

0.1.x Releases

Meerschaum's first point release focused on a lot, but mainly stability and improving important functionality, such as syncing.

0.0.x Releases

A lot was accomplished in the first 60 releases of Meerschaum. For the most part, the groundwork for core concepts like pipes, syncing, the config system, SQL and API connectors, bulk inserts, and more was laid.