Fix table function docs

rschu1ze · rschu1ze · commit 452951179962 · 2023-05-06T15:01:24.000Z
diff --git a/src/TableFunctions/TableFunctionDeltaLake.cpp b/src/TableFunctions/TableFunctionDeltaLake.cpp
@@ -20,7 +20,12 @@ using TableFunctionDeltaLake = ITableFunctionDataLake<TableFunctionDeltaLakeName
 
 void registerTableFunctionDeltaLake(TableFunctionFactory & factory)
 {
-    factory.registerFunction<TableFunctionDeltaLake>({.allow_readonly = false});
+    factory.registerFunction<TableFunctionDeltaLake>(
+        {.documentation = {
+            .description=R"(The table function can be used to read the DeltaLake table stored on object store.)",
+            .examples{{"deltaLake", "SELECT * FROM deltaLake(url, access_key_id, secret_access_key)", ""}},
+            .categories{"DataLake"}},
+         .allow_readonly = false});
 }
 
 }
diff --git a/src/TableFunctions/TableFunctionExplain.cpp b/src/TableFunctions/TableFunctionExplain.cpp
@@ -147,7 +147,16 @@ InterpreterExplainQuery TableFunctionExplain::getInterpreter(ContextPtr context)
 
 void registerTableFunctionExplain(TableFunctionFactory & factory)
 {
-    factory.registerFunction<TableFunctionExplain>();
+    factory.registerFunction<TableFunctionExplain>({.documentation = {
+            .description=R"(
+                Returns result of EXPLAIN query.
+                The function should not be called directly but can be invoked via `SELECT * FROM (EXPLAIN <query>)`.
+                You can use this query to process the result of EXPLAIN further using SQL (e.g., in tests).
+                Example:
+                [example:1]
+                )",
+            .examples={{"1", "SELECT explain FROM (EXPLAIN AST SELECT * FROM system.numbers) WHERE explain LIKE '%Asterisk%'", ""}}
+        }});
 }
 
 }
diff --git a/src/TableFunctions/TableFunctionZeros.cpp b/src/TableFunctions/TableFunctionZeros.cpp
@@ -48,8 +48,30 @@ StoragePtr TableFunctionZeros<multithreaded>::executeImpl(const ASTPtr & ast_fun
 
 void registerTableFunctionZeros(TableFunctionFactory & factory)
 {
-    factory.registerFunction<TableFunctionZeros<true>>();
-    factory.registerFunction<TableFunctionZeros<false>>();
+    factory.registerFunction<TableFunctionZeros<true>>({.documentation = {
+            .description=R"(
+                Generates a stream of zeros (a table with one column 'zero' of type 'UInt8') of specified size.
+                This table function is used in performance tests, where you want to spend as little time as possible to data generation while testing some other parts of queries.
+                In contrast to the `zeros_mt`, this table function is using single thread for data generation.
+                Example:
+                [example:1]
+                This query will test the speed of `randomPrintableASCII` function using single thread.
+                See also the `system.zeros` table.)",
+            .examples={{"1", "SELECT count() FROM zeros(100000000) WHERE NOT ignore(randomPrintableASCII(10))", ""}}
+    }});
+
+    factory.registerFunction<TableFunctionZeros<false>>({.documentation = {
+            .description=R"(
+                Generates a stream of zeros (a table with one column 'zero' of type 'UInt8') of specified size.
+                This table function is used in performance tests, where you want to spend as little time as possible to data generation while testing some other parts of queries.
+                In contrast to the `zeros`, this table function is using multiple threads for data generation, according to the `max_threads` setting.
+                Example:
+                [example:1]
+                This query will test the speed of `randomPrintableASCII` function using multiple threads.
+                See also the `system.zeros` table.
+                )",
+            .examples={{"1", "SELECT count() FROM zeros_mt(1000000000) WHERE NOT ignore(randomPrintableASCII(10))", ""}}
+}});
 }
 
 template <bool multithreaded>

Original file line number	Diff line number	Diff line change
`@@ -20,7 +20,12 @@ using TableFunctionDeltaLake = ITableFunctionDataLake<TableFunctionDeltaLakeName`
`20`	`20`
`21`	`21`	`void registerTableFunctionDeltaLake(TableFunctionFactory & factory)`
`22`	`22`	`{`
`23`		`- factory.registerFunction<TableFunctionDeltaLake>({.allow_readonly = false});`
	`23`	`+ factory.registerFunction<TableFunctionDeltaLake>(`
	`24`	`+ {.documentation = {`
	`25`	`+ .description=R"(The table function can be used to read the DeltaLake table stored on object store.)",`
	`26`	`+ .examples{{"deltaLake", "SELECT * FROM deltaLake(url, access_key_id, secret_access_key)", ""}},`
	`27`	`+ .categories{"DataLake"}},`
	`28`	`+ .allow_readonly = false});`
`24`	`29`	`}`
`25`	`30`
`26`	`31`	`}`
Original file line number	Diff line number	Diff line change
`@@ -147,7 +147,16 @@ InterpreterExplainQuery TableFunctionExplain::getInterpreter(ContextPtr context)`
`147`	`147`
`148`	`148`	`void registerTableFunctionExplain(TableFunctionFactory & factory)`
`149`	`149`	`{`
`150`		`- factory.registerFunction<TableFunctionExplain>();`
	`150`	`+ factory.registerFunction<TableFunctionExplain>({.documentation = {`
	`151`	`+ .description=R"(`
	`152`	`+ Returns result of EXPLAIN query.`
	`153`	+ The function should not be called directly but can be invoked via `SELECT * FROM (EXPLAIN <query>)`.
	`154`	`+ You can use this query to process the result of EXPLAIN further using SQL (e.g., in tests).`
	`155`	`+ Example:`
	`156`	`+ [example:1]`
	`157`	`+ )",`
	`158`	`+ .examples={{"1", "SELECT explain FROM (EXPLAIN AST SELECT * FROM system.numbers) WHERE explain LIKE '%Asterisk%'", ""}}`
	`159`	`+ }});`
`151`	`160`	`}`
`152`	`161`
`153`	`162`	`}`