How show command works internally in teradata?
When we run show command it lists the object definition. I believe it will query the dictionary tables and rebuild .
Could you help us to understand how it queries the internal tables?
teradata
asked Jun 9 '18 at 4:59
user153083user153083
1
bumped to the homepage by Community♦ 11 mins ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
add a comment |
When we run show command it lists the object definition. I believe it will query the dictionary tables and rebuild .
Could you help us to understand how it queries the internal tables?
teradata
asked Jun 9 '18 at 4:59
user153083user153083
1
bumped to the homepage by Community♦ 11 mins ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
Show what, exactly? Is this the CLI client? I've never heard of aSHOWorDESCRIBEthat rebulids anything. I think that PostgreSQL's client has an option that lets you do something like this. Please give the (exact) command you are running and the result yiu hope to obtain.
– Vérace
Jun 9 '18 at 11:03
When we use show command to get the DDL of the object. ex: show table db.tablename; show view db.viewname; I am trying to understand how show table results the DDL and what tables it is querying to get the output.
– user153083
Jun 11 '18 at 4:38
add a comment |
When we run show command it lists the object definition. I believe it will query the dictionary tables and rebuild .
Could you help us to understand how it queries the internal tables?
teradata
asked Jun 9 '18 at 4:59
user153083user153083
1
When we run show command it lists the object definition. I believe it will query the dictionary tables and rebuild .
Could you help us to understand how it queries the internal tables?
teradata
teradata
asked Jun 9 '18 at 4:59
user153083user153083
1
asked Jun 9 '18 at 4:59
user153083user153083
1
asked Jun 9 '18 at 4:59
user153083user153083
1
asked Jun 9 '18 at 4:59
user153083user153083
1
asked Jun 9 '18 at 4:59
user153083user153083
1
1
bumped to the homepage by Community♦ 11 mins ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
bumped to the homepage by Community♦ 11 mins ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
Show what, exactly? Is this the CLI client? I've never heard of aSHOWorDESCRIBEthat rebulids anything. I think that PostgreSQL's client has an option that lets you do something like this. Please give the (exact) command you are running and the result yiu hope to obtain.
– Vérace
Jun 9 '18 at 11:03
When we use show command to get the DDL of the object. ex: show table db.tablename; show view db.viewname; I am trying to understand how show table results the DDL and what tables it is querying to get the output.
– user153083
Jun 11 '18 at 4:38
add a comment |
Show what, exactly? Is this the CLI client? I've never heard of aSHOWorDESCRIBEthat rebulids anything. I think that PostgreSQL's client has an option that lets you do something like this. Please give the (exact) command you are running and the result yiu hope to obtain.
– Vérace
Jun 9 '18 at 11:03
When we use show command to get the DDL of the object. ex: show table db.tablename; show view db.viewname; I am trying to understand how show table results the DDL and what tables it is querying to get the output.
– user153083
Jun 11 '18 at 4:38
Show what, exactly? Is this the CLI client? I've never heard of a
SHOW or DESCRIBE that rebulids anything. I think that PostgreSQL's client has an option that lets you do something like this. Please give the (exact) command you are running and the result yiu hope to obtain.– Vérace
Jun 9 '18 at 11:03
Show what, exactly? Is this the CLI client? I've never heard of a
SHOW or DESCRIBE that rebulids anything. I think that PostgreSQL's client has an option that lets you do something like this. Please give the (exact) command you are running and the result yiu hope to obtain.– Vérace
Jun 9 '18 at 11:03
When we use show command to get the DDL of the object. ex: show table db.tablename; show view db.viewname; I am trying to understand how show table results the DDL and what tables it is querying to get the output.
– user153083
Jun 11 '18 at 4:38
When we use show command to get the DDL of the object. ex: show table db.tablename; show view db.viewname; I am trying to understand how show table results the DDL and what tables it is querying to get the output.
– user153083
Jun 11 '18 at 4:38
add a comment |
1 Answer
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oldest
votes
For a SHOW TABLE the parser actually creates the CREATE TABLE based on the current definition.
But for SHOW VIEW, etc. it's retrieving the CREATE from dbc.TablesV.RequestText. If the source code is larger than 12.5 KB RequestTxtOverFlow is set and the remainder is found in one or more 32 KB chunks in dbc.TextTbl.
For SHOW PROCEDURE it's different, this returns the internally stored sorce code (unless the SP is created with the NOSPL option), there's no way to access this info using a Select.
answered Jun 9 '18 at 21:33
dnoethdnoeth
3,746612
Thanks for the answer. For Requesttext column in dbc.tablesv for views and dbc.tvm for tables returns the text of the most recent data definition statement If you perform alter on view or table at that time requesttext column returns alter statement.show command still shows the DDL instead of alter. It will considers the data of requesttext column and does some internal operations / manipulations on dictionary tables and gets the data. Not sure how exactly it works.
– user153083
Jun 11 '18 at 4:32
As I wrote: for Tables the parser creates the DDL (this info is returned by the Resolver accessing the metadata stored in the Table Header on each AMP), but for views, etc. it's in RequestText.
– dnoeth
Jun 11 '18 at 5:57
add a comment |
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For a SHOW TABLE the parser actually creates the CREATE TABLE based on the current definition.
But for SHOW VIEW, etc. it's retrieving the CREATE from dbc.TablesV.RequestText. If the source code is larger than 12.5 KB RequestTxtOverFlow is set and the remainder is found in one or more 32 KB chunks in dbc.TextTbl.
For SHOW PROCEDURE it's different, this returns the internally stored sorce code (unless the SP is created with the NOSPL option), there's no way to access this info using a Select.
answered Jun 9 '18 at 21:33
dnoethdnoeth
3,746612
Thanks for the answer. For Requesttext column in dbc.tablesv for views and dbc.tvm for tables returns the text of the most recent data definition statement If you perform alter on view or table at that time requesttext column returns alter statement.show command still shows the DDL instead of alter. It will considers the data of requesttext column and does some internal operations / manipulations on dictionary tables and gets the data. Not sure how exactly it works.
– user153083
Jun 11 '18 at 4:32
As I wrote: for Tables the parser creates the DDL (this info is returned by the Resolver accessing the metadata stored in the Table Header on each AMP), but for views, etc. it's in RequestText.
– dnoeth
Jun 11 '18 at 5:57
add a comment |
For a SHOW TABLE the parser actually creates the CREATE TABLE based on the current definition.
But for SHOW VIEW, etc. it's retrieving the CREATE from dbc.TablesV.RequestText. If the source code is larger than 12.5 KB RequestTxtOverFlow is set and the remainder is found in one or more 32 KB chunks in dbc.TextTbl.
For SHOW PROCEDURE it's different, this returns the internally stored sorce code (unless the SP is created with the NOSPL option), there's no way to access this info using a Select.
answered Jun 9 '18 at 21:33
dnoethdnoeth
3,746612
Thanks for the answer. For Requesttext column in dbc.tablesv for views and dbc.tvm for tables returns the text of the most recent data definition statement If you perform alter on view or table at that time requesttext column returns alter statement.show command still shows the DDL instead of alter. It will considers the data of requesttext column and does some internal operations / manipulations on dictionary tables and gets the data. Not sure how exactly it works.
– user153083
Jun 11 '18 at 4:32
As I wrote: for Tables the parser creates the DDL (this info is returned by the Resolver accessing the metadata stored in the Table Header on each AMP), but for views, etc. it's in RequestText.
– dnoeth
Jun 11 '18 at 5:57
add a comment |
For a SHOW TABLE the parser actually creates the CREATE TABLE based on the current definition.
But for SHOW VIEW, etc. it's retrieving the CREATE from dbc.TablesV.RequestText. If the source code is larger than 12.5 KB RequestTxtOverFlow is set and the remainder is found in one or more 32 KB chunks in dbc.TextTbl.
For SHOW PROCEDURE it's different, this returns the internally stored sorce code (unless the SP is created with the NOSPL option), there's no way to access this info using a Select.
answered Jun 9 '18 at 21:33
dnoethdnoeth
3,746612
For a SHOW TABLE the parser actually creates the CREATE TABLE based on the current definition.
But for SHOW VIEW, etc. it's retrieving the CREATE from dbc.TablesV.RequestText. If the source code is larger than 12.5 KB RequestTxtOverFlow is set and the remainder is found in one or more 32 KB chunks in dbc.TextTbl.
For SHOW PROCEDURE it's different, this returns the internally stored sorce code (unless the SP is created with the NOSPL option), there's no way to access this info using a Select.
answered Jun 9 '18 at 21:33
dnoethdnoeth
3,746612
answered Jun 9 '18 at 21:33
dnoethdnoeth
3,746612
answered Jun 9 '18 at 21:33
dnoethdnoeth
3,746612
answered Jun 9 '18 at 21:33
dnoethdnoeth
3,746612
3,746612
Thanks for the answer. For Requesttext column in dbc.tablesv for views and dbc.tvm for tables returns the text of the most recent data definition statement If you perform alter on view or table at that time requesttext column returns alter statement.show command still shows the DDL instead of alter. It will considers the data of requesttext column and does some internal operations / manipulations on dictionary tables and gets the data. Not sure how exactly it works.
– user153083
Jun 11 '18 at 4:32
As I wrote: for Tables the parser creates the DDL (this info is returned by the Resolver accessing the metadata stored in the Table Header on each AMP), but for views, etc. it's in RequestText.
– dnoeth
Jun 11 '18 at 5:57
add a comment |
Thanks for the answer. For Requesttext column in dbc.tablesv for views and dbc.tvm for tables returns the text of the most recent data definition statement If you perform alter on view or table at that time requesttext column returns alter statement.show command still shows the DDL instead of alter. It will considers the data of requesttext column and does some internal operations / manipulations on dictionary tables and gets the data. Not sure how exactly it works.
– user153083
Jun 11 '18 at 4:32
As I wrote: for Tables the parser creates the DDL (this info is returned by the Resolver accessing the metadata stored in the Table Header on each AMP), but for views, etc. it's in RequestText.
– dnoeth
Jun 11 '18 at 5:57
Thanks for the answer. For Requesttext column in dbc.tablesv for views and dbc.tvm for tables returns the text of the most recent data definition statement If you perform alter on view or table at that time requesttext column returns alter statement.show command still shows the DDL instead of alter. It will considers the data of requesttext column and does some internal operations / manipulations on dictionary tables and gets the data. Not sure how exactly it works.
– user153083
Jun 11 '18 at 4:32
Thanks for the answer. For Requesttext column in dbc.tablesv for views and dbc.tvm for tables returns the text of the most recent data definition statement If you perform alter on view or table at that time requesttext column returns alter statement.show command still shows the DDL instead of alter. It will considers the data of requesttext column and does some internal operations / manipulations on dictionary tables and gets the data. Not sure how exactly it works.
– user153083
Jun 11 '18 at 4:32
As I wrote: for Tables the parser creates the DDL (this info is returned by the Resolver accessing the metadata stored in the Table Header on each AMP), but for views, etc. it's in RequestText.
– dnoeth
Jun 11 '18 at 5:57
As I wrote: for Tables the parser creates the DDL (this info is returned by the Resolver accessing the metadata stored in the Table Header on each AMP), but for views, etc. it's in RequestText.
– dnoeth
Jun 11 '18 at 5:57
add a comment |
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Show what, exactly? Is this the CLI client? I've never heard of a
SHOWorDESCRIBEthat rebulids anything. I think that PostgreSQL's client has an option that lets you do something like this. Please give the (exact) command you are running and the result yiu hope to obtain.– Vérace
Jun 9 '18 at 11:03
When we use show command to get the DDL of the object. ex: show table db.tablename; show view db.viewname; I am trying to understand how show table results the DDL and what tables it is querying to get the output.
– user153083
Jun 11 '18 at 4:38