alter\_table(table\_name=None, action=None, value=None, options={"{"}{"}"})\[source]

Apply various modifications to a table or view. The available modifications include the following:

Manage a table’s columns–a column can be added, removed, or have its type and properties modified, including whether it is dictionary encoded or not.

External tables cannot be modified except for their refresh method.

Create or delete a column, low-cardinality index, chunk skip, geospatial, CAGRA, or HNSW index. This can speed up certain operations when using expressions containing equality or relational operators on indexed columns. This only applies to tables.

Create or delete a foreign key on a particular column.

Manage a range-partitioned or a manual list-partitioned table’s partitions.

Set (or reset) the tier strategy of a table or view.

Refresh and manage the refresh mode of a materialized view or an external table.

Set the time-to-live (TTL). This can be applied to tables or views.

Set the global access mode (i.e. locking) for a table. This setting trumps any role-based access controls that may be in place; e.g., a user with write access to a table marked read-only will not be able to insert records into it. The mode can be set to read-only, write-only, read/write, and no access.

Parameters

table\_name (str) –

Table on which the operation will be performed, in \[schema\_name.]table\_name format, using standard name resolution rules. Must be an existing table or view.

action (str) –

Modification operation to be applied. Allowed values are:

create\_index – Creates a column (attribute) index, low-cardinality index, chunk skip index, geospatial index, CAGRA index, or HNSW index (depending on the specified index\_type), on the column name specified in input parameter value. If this column already has the specified index, an error will be returned.
refresh\_index – Refreshes an index identified by index\_type, on the column name specified in input parameter value. Currently applicable only to CAGRA indices.
delete\_index – Deletes a column (attribute) index, low-cardinality index, chunk skip index, geospatial index, CAGRA index, or HNSW index (depending on the specified index\_type), on the column name specified in input parameter value. If this column does not have the specified index, an error will be returned.
move\_to\_collection – \[DEPRECATED–please use move\_to\_schema and use GPUdb.create\_schema() to create the schema if non-existent] Moves a table or view into a schema named input parameter value. If the schema provided is non-existent, it will be automatically created.
move\_to\_schema – Moves a table or view into a schema named input parameter value. If the schema provided is nonexistent, an error will be thrown. If input parameter value is empty, then the table or view will be placed in the user’s default schema.
protected – No longer used. Previously set whether the given input parameter table\_name should be protected or not. The input parameter value would have been either ‘true’ or ‘false’.
rename\_table – Renames a table or view to input parameter value. Has the same naming restrictions as tables.
ttl – Sets the time-to-live in minutes of the table or view specified in input parameter table\_name.
add\_comment – Adds the comment specified in input parameter value to the table specified in input parameter table\_name. Use column\_name to set the comment for a column.
add\_column – Adds the column specified in input parameter value to the table specified in input parameter table\_name. Use column\_type and column\_properties in input parameter options to set the column’s type and properties, respectively.
change\_column – Changes type and properties of the column specified in input parameter value. Use column\_type and column\_properties in input parameter options to set the column’s type and properties, respectively. Note that primary key and/or shard key columns cannot be changed. All unchanging column properties must be listed for the change to take place, e.g., to add dictionary encoding to an existing ‘char4’ column, both ‘char4’ and ‘dict’ must be specified in the input parameter options map.
delete\_column – Deletes the column specified in input parameter value from the table specified in input parameter table\_name.
set\_default – Sets or replaces the default value expression for the column specified in input parameter value. The new default is taken from add\_column\_expression. Existing properties on the column are preserved.
delete\_default – Removes the default value expression from the column specified in input parameter value. Other column properties are preserved.
create\_foreign\_key – Creates a foreign key specified in input parameter value using the format ‘(source\_column\_name \[, …]) references target\_table\_name(primary\_key\_column\_name \[, …]) \[as foreign\_key\_name]’.
delete\_foreign\_key – Deletes a foreign key. The input parameter value should be the foreign\_key\_name specified when creating the key or the complete string used to define it.
add\_partition – Adds the partition specified in input parameter value, to either a range-partitioned or manual list-partitioned table.
remove\_partition – Removes the partition specified in input parameter value (and relocates all of its data to the default partition) from either a range-partitioned or manual list-partitioned table.
delete\_partition – Deletes the partition specified in input parameter value (and all of its data) from either a range-partitioned or manual list-partitioned table.
set\_global\_access\_mode – Sets the global access mode (i.e. locking) for the table specified in input parameter table\_name. Specify the access mode in input parameter value. Valid modes are ‘no\_access’, ‘read\_only’, ‘write\_only’ and ‘read\_write’.
refresh – For a materialized view, replays all the table creation commands required to create the view. For an external table, reloads all data in the table from its associated source files or data source.
set\_refresh\_method – For a materialized view, sets the method by which the view is refreshed to the method specified in input parameter value - one of ‘manual’, ‘periodic’, or ‘on\_change’. For an external table, sets the method by which the table is refreshed to the method specified in input parameter value - either ‘manual’ or ‘on\_start’.
set\_refresh\_start\_time – Sets the time to start periodic refreshes of this materialized view to the datetime string specified in input parameter value with format ‘YYYY-MM-DD HH:MM:SS’. Subsequent refreshes occur at the specified time + N \* the refresh period.
set\_refresh\_stop\_time – Sets the time to stop periodic refreshes of this materialized view to the datetime string specified in input parameter value with format ‘YYYY-MM-DD HH:MM:SS’.
set\_refresh\_period – Sets the time interval in seconds at which to refresh this materialized view to the value specified in input parameter value. Also, sets the refresh method to periodic if not already set.
set\_refresh\_span – Sets the future time-offset(in seconds) for the view refresh to stop.
set\_refresh\_execute\_as – Sets the user name to refresh this materialized view to the value specified in input parameter value.
remove\_text\_search\_attributes – Removes text search attribute from all columns.
remove\_shard\_keys – Removes the shard key property from all columns, so that the table will be considered randomly sharded. The data is not moved. The input parameter value is ignored.
set\_strategy\_definition – Sets the tier strategy for the table and its columns to the one specified in input parameter value, replacing the existing tier strategy in its entirety.
cancel\_datasource\_subscription – Permanently unsubscribe a data source that is loading continuously as a stream. The data source can be Kafka / S3 / Azure / GCS.
drop\_datasource\_subscription – Permanently delete a cancelled data source subscription.
pause\_datasource\_subscription – Temporarily unsubscribe a data source that is loading continuously as a stream. The data source can be Kafka / S3 / Azure / GCS.
resume\_datasource\_subscription – Resubscribe to a paused data source subscription. The data source can be Kafka / S3 / Azure / GCS.
change\_owner – Change the owner resource group of the table.
set\_load\_vectors\_policy – Set startup data loading scheme for the table; see description of ‘load\_vectors\_policy’ in GPUdb.create\_table() for possible values for input parameter value.
set\_build\_pk\_index\_policy – Set startup primary key generation scheme for the table; see description of ‘build\_pk\_index\_policy’ in GPUdb.create\_table() for possible values for input parameter value.
set\_build\_materialized\_view\_policy – Set startup rebuilding scheme for the materialized view; see description of ‘build\_materialized\_view\_policy’ in GPUdb.create\_materialized\_view() for possible values for input parameter value.
rebuild\_text\_search\_index – Drops and rebuilds the text search index for the table from current type metadata and chunk storage. Use this to repair a text-search index left incomplete by an interrupted or failed rebuild (for example, after a crash during an add-column that requested text search): re-running the original add\_column will not work because the column already exists. This action is also dispatched automatically by GPUdb.alter\_table\_columns() after add\_column completions that require a full re-index. The input parameter value is ignored.

value (str) –

The value of the modification, depending on input parameter action. For example, if input parameter action is add\_column, this would be the column name; while the column’s definition would be covered by the column\_type, column\_properties, column\_default\_value, and add\_column\_expression in input parameter options. If input parameter action is ttl, it would be the number of minutes for the new TTL. If input parameter action is refresh, this field would be blank.

options (dict of str to str) –

Optional parameters. Allowed keys are:

action
column\_name
table\_name
column\_default\_value – When adding a column, set a literal default value for existing records. For nullable columns, the default value will be null, regardless of data type. Also persisted as the column’s default for future inserts that omit the column.
column\_properties – When adding or changing a column, set the column properties (strings, separated by a comma: data, text\_search, char8, int8 etc).
column\_type – When adding or changing a column, set the column type (strings, separated by a comma: int, double, string, null etc).
copy\_values\_from\_column – \[DEPRECATED] Please use add\_column\_expression instead.
rename\_column – When changing a column, specify new column name.
validate\_change\_column – When changing a column, validate the change before applying it (or not). Allowed values are:
- true – Validate all values. A value too large (or too long) for the new type will prevent any change.
- false – When a value is too large or long, it will be truncated.
The default value is ‘true’.
update\_last\_access\_time – Indicates whether the time-to-live (TTL) expiration countdown timer should be reset to the table’s TTL. Allowed values are:
- true – Reset the expiration countdown timer to the table’s configured TTL.
- false – Don’t reset the timer; expiration countdown will continue from where it is, as if the table had not been accessed.
The default value is ‘true’.
add\_column\_expression – When adding a column or setting a new default with input parameter action set to set\_default, the new default expression (GPUdb-syntax) for the column. Any valid expression may be used, including one containing references to existing columns in the same table. Persisted as the column’s default for future inserts that omit the column; for add\_column, also used to backfill existing rows.
add\_column\_expression\_sql – Optional SQL-syntax form of add\_column\_expression, used only when the SQL syntax differs from the GPUdb syntax. Persisted alongside the GPUdb form so SHOW CREATE TABLE / information\_schema can reproduce the original SQL.
strategy\_definition – Parameter for specifying the tier strategy for the table and its columns when input parameter action is set\_strategy\_definition, replacing the existing tier strategy in its entirety.
index\_type – Type of index to create, when input parameter action is create\_index; to refresh, when input parameter action is refresh\_index; or to delete, when input parameter action is delete\_index. Allowed values are:
- column – Create or delete a column (attribute) index.
- low\_cardinality – Create a low-cardinality column (attribute) index.
- chunk\_skip – Create or delete a chunk skip index.
- geospatial – Create or delete a geospatial index.
- cagra – Create or delete a CAGRA index on a vector column.
- hnsw – Create or delete an HNSW index on a vector column.
The default value is ‘column’.
index\_options – Options to use when creating an index, in the format “key: value \[, key: value \[, …]]”. Valid options vary by index type.

The default value is an empty dict ( {"{"}{"}"} ).

Returns

A dict with the following entries–

table\_name (str) –

Table on which the operation was performed.

action (str) –

Modification operation that was performed.

value (str) –

The value of the modification that was performed.

type\_id (str) –

Return the type\_id (when changing a table, a new type may be created).

type\_definition (str) –

Return the type\_definition (when changing a table, a new type may be created).

properties (dict of str to lists of str) –

Return the type properties (when changing a table, a new type may be created).

label (str) –

Return the type label (when changing a table, a new type may be created).

info (dict of str to str) –

Additional information.