Discussion thread | https://lists.apache.org/thread/l5xx9lgg70y6cbktk810yv4xzx701b0454fyd27m8on1cf3hn6dz564zqmkobjyd | ||||||||
---|---|---|---|---|---|---|---|---|---|
Vote thread | https://lists.apache.org/thread/bc0qcmg73t4q7do3k657rqcdx1vyjqzy | ||||||||
JIRA |
| ||||||||
Release |
Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).
...
But these features are not very complete compared with other popular engines such as spark, hive, presto and commercial engines such as snowflake.
For example, many popular engines support show operation with filtering except flink, and support describe many objects(flink only supports describe table).
And these improved features are very useful for users or developers.
show | Support or Not | Support filter or Not |
show tables | Yes | Yes |
show columns | Yes | Yes |
show catalogs | Yes | No |
show databases | Yes | No |
show functions | Yes | No |
show views | Yes | No |
show modules | Yes | No |
show jars | Yes | No |
show jobs | Yes | No |
We can see current flink many sql statements only support showing with full datas, without 'FROM/IN' or 'LIKE' filter clause.
show create | Support or Not |
show create database | No |
show create table | Yes |
show create view | Yes |
show create function | No |
describe | Support or Not |
describe catalog | No |
describe database | No |
describe table | Yes |
describe function | No |
describe view | No |
current flink only supports describing tables.
So we propose this flip, try to support these features.
Proposed Syntax Changes:
We compare flink with other popular engines and give an improved syntax example. Welcome everyone to discuss and improve the final syntax.
and developers.
Comparison with other popular engines
Because each engine has its own personalized auxiliary sql statements features, here are some common operations listed as much as possible, and compare what other unrealized abilities of flink.
We focus on standard sql, but also consider absorbing the syntax of some mature engines to let users know that this is not standard, just for better use (e.g. ILIKE).
show catalogs
Engine | Support or Not, If support show the syntax |
Flink | SHOW CATALOGS |
Spark | No |
Hive | No |
Presto | SHOW CATALOGS [ LIKE pattern ] |
MySQL | No |
SnowFlake | No |
show databases
Engine | Support or Not, If support show the syntax |
Flink | SHOW DATABASES |
Spark | SHOW { DATABASES | SCHEMAS } [ LIKE regex_pattern ] |
Hive | SHOW (DATABASES|SCHEMAS) [LIKE 'identifier_with_wildcards'] |
Presto | SHOW SCHEMAS [ FROM catalog ] [ LIKE pattern ] |
MySQL | SHOW {DATABASES | SCHEMAS} [LIKE 'pattern' | WHERE expr] |
SnowFlake | SHOW [ TERSE ] DATABASES [ HISTORY ] [ LIKE '<pattern>' ] [ STARTS WITH '<name_string>' ] [ LIMIT <rows> [ FROM '<name_string>' ] ] |
show functions
Engine | Support or Not, If support show the syntax |
Flink | SHOW [USER] FUNCTIONS |
Spark | SHOW [ function_kind ] FUNCTIONS [ { FROM | IN } database_name ] [ LIKE regex_pattern ] |
Hive | SHOW FUNCTIONS [LIKE "<pattern>"] |
Presto | SHOW FUNCTIONS [ LIKE pattern [ ESCAPE 'escape_character' ] ] |
MySQL | SELECT ROUTINE_NAME FROM INFORMATION_SCHEMA.ROUTINES WHERE ROUTINE_TYPE = 'FUNCTION' ORDER BY ROUTINE_NAME; |
SnowFlake | SHOW FUNCTIONS [ LIKE '<pattern>' ] [ IN { ACCOUNT | DATABASE | DATABASE <database_name> | SCHEMA | SCHEMA <schema_name> | <schema_name> } ] |
show views
Engine | Support or Not, If support show the syntax |
Flink | SHOW VIEWS |
Spark | SHOW VIEWS [ { FROM | IN } database_name ] [ LIKE regex_pattern ] |
Hive | SHOW VIEWS [IN/FROM database_name] [LIKE 'pattern_with_wildcards'] |
Presto | No |
MySQL | SHOW FULL TABLES [FROM db_name] [LIKE 'pattern' | WHERE expr] (Alternative syntax) |
SnowFlake | SHOW [ TERSE ] VIEWS [ LIKE '<pattern>' ] [ IN { ACCOUNT | DATABASE [ <db_name> ] | [ SCHEMA ] [ <schema_name> ] } ] [ STARTS WITH '<name_string>' ] [ LIMIT <rows> [ FROM '<name_string>' ] ] |
show modules
Engine | Support or Not, If support show the syntax |
Flink | SHOW [FULL] MODULES |
Spark | No |
Hive | No |
Presto | No |
MySQL | No |
SnowFlake | No |
show jars
Engine | Support or Not, If support show the syntax | Note |
Flink | SHOW JARS | only work in SQL CLI or SQL Gateway. |
Spark | No | |
Hive | No | |
Presto | No | |
MySQL | No | |
SnowFlake | No |
show jobs
Engine | Support or Not, If support show the syntax | Note |
Flink | SHOW JOBS | only work in SQL CLI or SQL Gateway. |
Spark | No | |
Hive | No | |
Presto | No | |
MySQL | No | |
SnowFlake | No |
show create database
Engine | Support or Not, If support show the syntax | Note |
Flink | No | |
Spark | No | |
Hive | No | |
Presto | No | |
MySQL | SHOW CREATE {DATABASE | SCHEMA} [IF NOT EXISTS] db_name | RDBMS, such as Oracle, MariaDB, TiDB also support it. |
SnowFlake | No |
show create function
Engine | Support or Not, If support show the syntaxes | Note |
Flink | No | |
Spark | No | |
Hive | No | |
Presto | SHOW CREATE FUNCTION function_name [ ( parameter_type[, ...] ) ] | |
MySQL | SHOW CREATE FUNCTION func_name | RDBMS, such as Oracle, MariaDB, TiDB also support it. |
SnowFlake | No |
describe catalog
Engine | Support or Not, If support show the syntaxes | Note |
Flink | No | with catalog-database-table three layer |
Spark | No | with database-table layer. schema and database they mean the same thing. But databricks on aws support it: |
Hive | No | with database-table layer. schema and database they mean the same thing |
Presto | No | Presto is schema-database-table three layer. schema and database are not equal. |
MySQL | No | with database-table layer. schema and database they mean the same thing. |
SnowFlake | DESC[RIBE] DATABASE <database_name> | SnowFlake is database-schema-table three layer. database may act as catalog. |
describe database
Engine | Support or Not, If support show the syntaxes | Note |
Flink | { DESC | DESCRIBE } DATABASE [ EXTENDED ] db_name | just sqlNode, but not expose to table & sql api |
Spark | { DESC | DESCRIBE } DATABASE [ EXTENDED ] db_name | |
Hive | DESCRIBE DATABASE [EXTENDED] db_name; DESCRIBE SCHEMA [EXTENDED] db_name; | |
Presto | No | |
MySQL | No | |
SnowFlake | DESC[RIBE] SCHEMA <schema_name> |
describe function
Engine | Support or Not, If support show the syntaxes | Note |
Flink | No | |
Spark | { DESC | DESCRIBE } FUNCTION [ EXTENDED ] function_name | |
Hive | DESCRIBEFUNCTION [EXTENDED] <function_name> | |
Presto | No | |
MySQL | No | |
SnowFlake | DESC[RIBE] FUNCTION <name> ( [ <arg_data_type> ] [ , ... ] ) |
describe view
Engine | Support or Not, If support show the syntaxes | Note |
Flink | No | |
Spark | No | |
Hive | DESCRIBE [EXTENDED|FORMATTED] <view_name>; | |
Presto | No | |
MySQL | No | |
SnowFlake | DESC[RIBE] VIEW <name> |
We can see many popular engines have filtering with show statements, support 'FROM/IN' or 'LIKE/ILIKE' filter clause except flink.
And currently flink only supports describing tables. And also some unique statements such as show jars/show modules in flink can also support this feature.
So we proposed this FLIP.
Proposed Syntax Changes:
Note: we both support LIKE and ILIKE in this FLIP.
LIKE: sql_like_pattern, case sensitive
ILIKE: sql_like_pattern, same behavior as LIKE except case insensitive
And For consistency, we will add ILIKE support for query either.
Because calcite already support parse ILIKE and exist SqlLikeOperator(SqlLibraryOperators.ILIKE, not std operator). We just need to support it in table & sql api (no need to modify sql keywords and Parser.jj).Because it may be modified under discuss, we put it on the google docs. please see FLIP-297: Improve Auxiliary Sql Statements Docs
before | after(under discussed) | Note | |
show catalogs | SHOW CATALOGS | SHOW CATALOGS[ [NOT] (LIKE | ILIKE) <sql_like_pattern> ] | |
show databases | SHOW DATABASES | SHOW DATABASES [ ( FROM | IN ) catalog_name] [ [NOT] (LIKE | ILIKE) <sql_like_pattern> ] | |
show tables | SHOW TABLES [ ( FROM | IN ) [catalog_name.]database_name ] [ [NOT] LIKE <sql_like_pattern> ] | SHOW TABLES [ ( FROM | IN ) [catalog_name.]database_name ] [ [NOT] (LIKE | ILIKE) <sql_like_pattern> ] | |
show columns | SHOW COLUMNS ( FROM | IN ) [[catalog_name.]database.]<table_name> [ [NOT] LIKE <sql_like_pattern>] | SHOW COLUMNS ( FROM | IN ) [[catalog_name.]database.]<table_name> [ [NOT] (LIKE | ILIKE) <sql_like_pattern>] | |
show functions | SHOW [USER] FUNCTIONS | SHOW [USER] FUNCTIONS [ ( FROM | IN ) [catalog_name.]database_name ] [ [NOT] (LIKE | ILIKE) <sql_like_pattern> ] | |
show views | SHOW VIEWS | SHOW VIEWS [ ( FROM | IN ) [catalog_name.]database_name ] [ [NOT] (LIKE | ILIKE) <sql_like_pattern> ] | |
show modules | SHOW [FULL] MODULES | SHOW [FULL] MODULES [ [NOT] (LIKE | ILIKE) <sql_like_pattern> ] | |
show jars | SHOW JARS | SHOW JARS [ [NOT] (LIKE | ILIKE) <sql_like_pattern> ] | only work in SQL CLI or SQL Gateway. |
show jobs | SHOW JOBS | SHOW JOBS [ [NOT] (LIKE | ILIKE) <sql_like_pattern> ] | only work in SQL CLI or SQL Gateway. |
describe catalog | Not Support | { DESCRIBE | DESC } CATALOG [ EXTENDED ] catalog_name If the optional | |
describe database | Not Support | { DESCRIBE | DESC } DATABASE [ EXTENDED ] [catalog_name.] |
database_name If the optional | ||
describe function | Not Support | { DESCRIBE | DESC } FUNCTION [ EXTENDED ] [[catalog_name.] |
database_name.]function |
describe query
Not Support
{ DESCRIBE | DESC } [ QUERY ] input_statement
Proposed TableEnvironment SQL API Changes:
Because `TableEnvironment` is a `@publicEvolving Api`, we may add these override methods or add some SupportsXXX interface to support these features.
details to be added.
Future Work
_name If the optional | |||
... |
Proposed CataLog API Changes:
No need to add new apis (there is a discussion about api changes, pls see the discuss thread).
We can use such as TableEnvironment.getCatalog(catalogName).get().listDatabases(), TableEnvironment.getCatalog(catalogName).get().listFunctions(databaseName) for util to get result.
In TableEnvironmentImpl we do filter for returned full results.
Some SqlNodes and Operations could be added or changed.
Code Block | ||||||
---|---|---|---|---|---|---|
| ||||||
// Add SqlDescribeCatalog & DescribeCatalogOperation
// Add SqlDescribeDatabase & DescribeDatabaseOperation
// Add SqlDescribeFunction & DescribeFunctionOperation
About DescribeCatalog:
+-------------------------+-----------------------------+
| catalog_description_item| catalog_description_value |
+-------------------------+-----------------------------+
| Catalog Name | xxx |
| Properties| (key1=val1, key2=val2, ...) |
+-------------------------+-----------------------------+
About DescribeDatabase:
+-------------------------+-----------------------------+
|database_description_item| database_description_value|
+-------------------------+-----------------------------+
| Database Name| employees|
| Description| For software companies|
| Properties| (key1=val1, key2=val2, ...) |
+-------------------------+-----------------------------+
About DescribeFunction:
+-------------------------+-----------------------------+
|function_description_item| function_description_value|
+-------------------------+-----------------------------+
| Function Name | ABS |
| Function Language| JAVA |
| Resource Uri | file://xxx |
| Details | details |
+-------------------------+-----------------------------+
The concrete describe infos we can get from the specific catalog object.
// Changed SqlNodes & Operations
// SqlShowCatalogs
public class SqlShowCatalogs extends SqlCall {
public static final SqlSpecialOperator OPERATOR =
new SqlSpecialOperator("SHOW CATALOGS", SqlKind.OTHER);
protected final SqlLikeType likeType;
protected final boolean notLike;
protected final SqlCharStringLiteral likeLiteral;
public SqlShowCatalogs(SqlParserPos pos) {
super(pos);
this.likeType = null;
this.notLike = false;
this.likeLiteral = null;
}
public SqlShowCatalogs(
SqlParserPos pos, String likeType, boolean notLike, SqlCharStringLiteral likeLiteral) {
super(pos);
if (likeType != null) {
this.likeType = SqlLikeType.of(likeType);
this.likeLiteral = requireNonNull(likeLiteral, "Like pattern must not be null");
} else {
this.likeType = null;
this.likeLiteral = null;
}
this.notLike = notLike;
}
public SqlLikeType getLikeType() {
return likeType;
}
public boolean isLike() {
return likeType == SqlLikeType.LIKE;
}
public boolean isILike() {
return likeType == SqlLikeType.ILIKE;
}
public boolean isWithLike() {
return isLike() || isILike();
}
public boolean isNotLike() {
return notLike;
}
public String getLikeSqlPattern() {
return Objects.isNull(likeLiteral) ? null : likeLiteral.getValueAs(String.class);
}
@Override
public SqlOperator getOperator() {
return OPERATOR;
}
@Override
public List<SqlNode> getOperandList() {
return Collections.emptyList();
}
@Override
public void unparse(SqlWriter writer, int leftPrec, int rightPrec) {
writer.keyword("SHOW CATALOGS");
if (isWithLike()) {
if (isNotLike()) {
writer.keyword(String.format("NOT %s '%s'", likeType.name(), getLikeSqlPattern()));
} else {
writer.keyword(String.format("%s '%s'", likeType.name(), getLikeSqlPattern()));
}
}
}
}
// ShowCatalogsOperation
public class ShowCatalogsOperation implements ShowOperation {
private final OperationLikeType likeType;
private final boolean notLike;
private final String likePattern;
/** Use when there is no sub-clause. */
public ShowCatalogsOperation() {
this.likeType = null;
this.notLike = false;
this.likePattern = null;
}
/** Use when there is like. */
public ShowCatalogsOperation(String likeType, boolean notLike, String likePattern) {
this.likeType = OperationLikeType.of(checkNotNull(likeType, "Like type must not be null"));
this.likePattern = checkNotNull(likePattern, "Like pattern must not be null");
this.notLike = notLike;
}
public boolean isLike() {
return likeType == OperationLikeType.LIKE;
}
public boolean isIlike() {
return likeType == OperationLikeType.ILIKE;
}
public boolean isWithLike() {
return isLike() || isIlike();
}
public boolean isNotLike() {
return notLike;
}
public String getLikePattern() {
return likePattern;
}
@Override
public String asSummaryString() {
StringBuilder builder = new StringBuilder().append("SHOW CATALOGS");
if (isWithLike()) {
if (notLike) {
builder.append(String.format(" NOT %s %s", likeType.name(), likePattern));
} else {
builder.append(String.format(" %s %s", likeType.name(), likePattern));
}
}
return builder.toString();
}
}
// SqlShowDatabases
public class SqlShowDatabases extends SqlCall {
public static final SqlSpecialOperator OPERATOR =
new SqlSpecialOperator("SHOW DATABASES", SqlKind.OTHER);
protected final String preposition;
protected final SqlIdentifier catalogName;
protected final SqlLikeType likeType;
protected final boolean notLike;
protected final SqlCharStringLiteral likeLiteral;
public SqlShowDatabases(SqlParserPos pos) {
super(pos);
this.preposition = null;
this.catalogName = null;
this.likeType = null;
this.notLike = false;
this.likeLiteral = null;
}
public SqlShowDatabases(
SqlParserPos pos,
String preposition,
SqlIdentifier catalogName,
String likeType,
boolean notLike,
SqlCharStringLiteral likeLiteral) {
super(pos);
this.preposition = preposition;
this.catalogName =
preposition != null
? requireNonNull(catalogName, "Catalog name must not be null.")
: null;
if (likeType != null) {
this.likeType = SqlLikeType.of(likeType);
this.likeLiteral = requireNonNull(likeLiteral, "Like pattern must not be null");
} else {
this.likeType = null;
this.likeLiteral = null;
}
this.notLike = notLike;
}
public String getPreposition() {
return preposition;
}
public SqlIdentifier getCatalogName() {
return catalogName;
}
public String catalogName() {
return catalogName != null ? catalogName.getSimple() : null;
}
public SqlLikeType getLikeType() {
return likeType;
}
public boolean isLike() {
return likeType == SqlLikeType.LIKE;
}
public boolean isILike() {
return likeType == SqlLikeType.ILIKE;
}
public boolean isNotLike() {
return notLike;
}
public boolean isWithLike() {
return isLike() || isILike();
}
public SqlCharStringLiteral getLikeLiteral() {
return likeLiteral;
}
public String getLikeSqlPattern() {
return Objects.isNull(likeLiteral) ? null : likeLiteral.getValueAs(String.class);
}
@Override
public SqlOperator getOperator() {
return OPERATOR;
}
@Override
public List<SqlNode> getOperandList() {
return Objects.isNull(this.catalogName)
? Collections.emptyList()
: Collections.singletonList(catalogName);
}
@Override
public void unparse(SqlWriter writer, int leftPrec, int rightPrec) {
if (this.preposition == null) {
writer.keyword("SHOW DATABASES");
} else if (catalogName != null) {
writer.keyword("SHOW DATABASES " + this.preposition);
catalogName.unparse(writer, leftPrec, rightPrec);
}
if (isWithLike()) {
if (isNotLike()) {
writer.keyword(String.format("NOT %s '%s'", likeType.name(), getLikeSqlPattern()));
} else {
writer.keyword(String.format("%s '%s'", likeType.name(), getLikeSqlPattern()));
}
}
}
// ShowDatabasesOperation
public class ShowDatabasesOperation implements ShowOperation {
private final String preposition;
private final String catalogName;
private final OperationLikeType likeType;
private final boolean notLike;
private final String likePattern;
/** Use when there is no sub-clause. */
public ShowDatabasesOperation() {
this.preposition = null;
this.catalogName = null;
this.likeType = null;
this.notLike = false;
this.likePattern = null;
}
/** Use when there is only like. */
public ShowDatabasesOperation(String likeType, boolean notLike, String likePattern) {
this.preposition = null;
this.catalogName = null;
this.likeType = OperationLikeType.of(checkNotNull(likeType, "Like type must not be null"));
this.likePattern = checkNotNull(likePattern, "Like pattern must not be null");
this.notLike = notLike;
}
/** Use when there is preposition. */
public ShowDatabasesOperation(
String preposition,
String catalogName,
String likeType,
boolean notLike,
String likePattern) {
this.preposition = checkNotNull(preposition, "Preposition must not be null");
this.catalogName = checkNotNull(catalogName, "Catalog name must not be null");
if (likeType != null) {
this.likeType = OperationLikeType.of(likeType);
this.likePattern = checkNotNull(likePattern, "Like pattern must not be null");
} else {
this.likeType = null;
this.likePattern = null;
}
this.notLike = notLike;
}
public String getPreposition() {
return preposition;
}
public String getCatalogName() {
return catalogName;
}
public boolean isLike() {
return likeType == OperationLikeType.LIKE;
}
public boolean isIlike() {
return likeType == OperationLikeType.ILIKE;
}
public boolean isWithLike() {
return isLike() || isIlike();
}
public boolean isNotLike() {
return notLike;
}
public String getLikePattern() {
return likePattern;
}
@Override
public String asSummaryString() {
StringBuilder builder = new StringBuilder().append("SHOW DATABASES");
if (preposition != null) {
builder.append(String.format(" %s %s", preposition, catalogName));
}
if (isWithLike()) {
if (notLike) {
builder.append(String.format(" NOT %s %s", likeType.name(), likePattern));
} else {
builder.append(String.format(" %s %s", likeType.name(), likePattern));
}
}
return builder.toString();
}
}
// omit here. basically same as ShowCatalogs/ShowDatabases above.
// SqlShowFunctions & ShowFunctionsOperation
// SqlShowViews & ShowViewsOperation
// SqlShowModules & ShowModulesOperation
// SqlShowJars & ShowJarsOperation
// SqlShowJobs & ShowJobsOperation |
Future Work
TBD.to be added
Compatibility, Deprecation, and Migration Plan
No compatibility and migrationmigration. We will ensure changes of this FLIP will be compatible with current flink behavior.
Test Plan
Add new cases to cover these features.
...