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Paul Rogers <par0328@yahoo.com>
committed
on 13 Jun
DRILL-7293: Convert the regex ("log") plugin to use EVF
Converts the log format plugin (which uses a regex for parsing) to work
with the Ext… Show more
DRILL-7293: Convert the regex ("log") plugin to use EVF

Converts the log format plugin (which uses a regex for parsing) to work

with the Extended Vector Format.

User-visible behavior changes added to the README file.

* Use the plugin config object to pass config to the Easy framework.

* Use the EVF scan mechanism in place of the legacy "ScanBatch"

mechanism.

* Minor code and README cleanup.

* Replace ad-hoc type conversion with builtin conversions

The provided schema support in the enhanced vector framework (EVF)

provides automatic conversions from VARCHAR to most types. The log

format plugin was created before EVF was available and provided its own

conversion mechanism. This commit removes the ad-hoc conversion code and

instead uses the log plugin config schema information to create an

"output schema" just as if it was provided by the provided schema

framework.

Because we need the schema in the plugin (rather than the reader), moved

the schema-parsing code out of the reader into the plugin. The plugin

creates two schemas: an "output schema" with the desired output types,

and a "reader schema" that uses only VARCHAR. This causes the EVF to

perform conversions.

* Enable provided schema support

Allows the user to specify types using either the format config (as

previously) or a provided schema. If a schema is provided, it will match

columns using names specified in the format config.

The provided schema can specify both types and modes (nullable or not

null.)

If a schema is provided, then the types specified in the plugin config

are ignored. No attempt is made to merge schemas.

If a schema is provided, but a column is omitted from the schema, the

type defaults to VARCHAR.

* Added ability to specify regex in table properties

Allows the user to specify the regex, and the column schema,

using a CREATE SCHEMA statement. The README file provides the details.

Unit tests demonstrate and verify the functionality.

* Used the custom error context provided by EVF to enhance the log format

reader error messages.

* Added user name to default EVF error context

* Added support for table functions

Can set the regex and maxErrors fields, but not the schema.

Schema will default to "field_0", "field_1", etc. of type

VARCHAR.

* Added unit tests to verify the functionality.

* Added a check, and a test, for a regex with no groups.

* Added columns array support

When the log regex plugin is given no schema, it previously

created a list of columns "field_0", "field_1", etc. After

this change, the plugin instead follows the pattern set by

the text plugin: it will place all fields into the columns

array. (The two special fields are still separate.)

A few adjustments were necessary to the columns array

framework to allow use of the special columns along with

the `columns` column.

Modified unit tests and the README to reflect this change.

The change should be backward compatible because few users

are likely relying on the dummy field names.

Added unit tests to verify that schema-based table

functions work. A test shows that, due to the unforunate

config property name "schema", users of this plugin cannot

combine a config table function with the schema attribute

in the way promised in DRILL-6965.

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