[jira] [Updated] (CARBONDATA-3519) A new column page MemoryBlock is allocated at each row addition to table page if having string column with local dictionary enabled.

[Akash R Nilugal (Jira)]

     [ https://issues.apache.org/jira/browse/CARBONDATA-3519?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Venugopal Reddy K updated CARBONDATA-3519:
------------------------------------------
    Description:
+*Issue-1:*+

{color:#0747a6}*Context:*{color}

For a string column with local dictionary enabled, a column page of

{{`{color:#de350b}UnsafeFixLengthColumnPage{color}` }}with datatype `{color:#de350b}{{DataTypes.BYTE_ARRAY}}{color}` is created for `{color:#de350b}{{encodedPage}}{color}` along with regular `{color:#de350b}{{actualPage}}{color}` of `{color:#de350b}{{UnsafeVarLengthColumnPage}}{color}`. 

We have `{color:#de350b}*{{capacity}}*{color}` field in the `{color:#de350b}{{UnsafeFixLengthColumnPage}}{color}`. And this field indicates the capacity of  allocated

`{color:#de350b}{{memoryBlock}}{color}` for the page. `{{{color:#de350b}ensureMemory{color}()}}` method gets called while adding rows to check if  `{color:#de350b}{{totalLength + requestSize > capacity}}{color}` to allocate a new memoryBlock. If there is no room to add the next row, allocates a new block, copy the old context(prev rows) and free the old memoryBlock.

{color:#0747a6} *Problem:*{color}

While, `{color:#de350b}{{UnsafeFixLengthColumnPage}}{color}` with with datatype `{color:#de350b}{{DataTypes.BYTE_ARRAY}}{color}` is created for `{color:#de350b}{{encodedPage}}{color}`, we have not assigned the *`{color:#de350b}{{capacity}}{color}`* field with allocated memory block size. Hence, for each add row to tablePage, *ensureMemory() check always fails*, allocates a new column page memoryBlock, copy the old context(prev rows) and free the old memoryBlock. This *allocation of new memoryBlock and free of old memoryBlock happens for each row row addition* for the string columns with local dictionary.

 

+*Issue-2:*+

{color:#0747a6}*Context:*{color}

In`{color:#de350b}VarLengthColumnPageBase{color}`, we have a `{color:#de350b}rowOffset{color}` column page of  `{color:#de350b}UnsafeFixLengthColumnPage{color}` of datatype `{color:#de350b}INT{color}`

to maintain the data offset to {color:#172b4d}each{color} row of variable length columns. This `{color:#de350b}rowOffset{color}` page allocates to be size of page. 

{color:#0747a6} *Problem:*{color}

{color:#0747a6}{color:#172b4d}If we have 10 rows in the page, we need 11 rows for its rowOffset page. Because we always keep 0 as offset to 1st row. So an additional row is required for rowOffset page[pasted code below to show the reference]. Otherwise, we ensureMemory() check always fails for the last row(10th row in this case) of data and allocates a new crowOffset page memoryBlock, copy the old context(prev rows) and free the old memoryBlock. This can happen for the string columns with local dictionary, direct dictionary columns, global disctionary columns.{color}**{color}

 
{code:java}
public abstract class VarLengthColumnPageBase extends ColumnPage {
...
@Override
public void putBytes(int rowId, byte[] bytes) {
 ...
 if (rowId == 0) {
 rowOffset.putInt(0, 0);
 }
 rowOffset.putInt(rowId + 1, rowOffset.getInt(rowId) + bytes.length);
 putBytesAtRow(rowId, bytes);
 totalLength += bytes.length;
}
...
}
 
{code}
 

  was:
*Context:*

For a string column with local dictionary enabled, a column page of

{{{color:#de350b}@UnsafeFixLengthColumnPage{color} }}with datatype `{color:#ff8b00}{{DataTypes.BYTE_ARRAY}}{color}` is created for `{{encodedPage}}` along with regular `{{actualPage}}` of `{{UnsafeVarLengthColumnPage}}`. 

We have `*{{capacity}}*` field in 

 the `{{UnsafeFixLengthColumnPage}}`. And this field indicates the capacity of  allocated

`{{memoryBlock}}` for the page. `{{ensureMemory()}}` method is being called while adding rows to check if 

`{{totalLength + requestSize > capacity}}` to allocate a new memoryBlock if there is no room to add the next row, copy the old context(prev rows) and free the old memoryBlock.

 

*Issues:*
 # While, `{{UnsafeFixLengthColumnPage}}` with with datatype `{{DataTypes.BYTE_ARRAY}}` is created for `{{encodedPage}}`, we have not assigned the *`{{capacity}}`* field with allocated memory block size. Hence, for each add row to tablePage, ensureMemory() check always fails, allocates a new column page memoryBlock, copy the old context(prev rows) and free the old memoryBlock. This allocation of new memoryBlock and free of old memoryBlock happens at row addition for the string columns with local dictionary enabled.
 # And in `VarLengthColumnPageBase`, we have a `rowOffset` column page of type `UnsafeFixLengthColumnPage` to maintain the offset to each row of variable length columns. This `rowOffset` page is 

> A new column page MemoryBlock is allocated at each row addition to table page if having string column with local dictionary enabled.
> -------------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: CARBONDATA-3519
>                 URL: https://issues.apache.org/jira/browse/CARBONDATA-3519
>             Project: CarbonData
>          Issue Type: Improvement
>          Components: core
>            Reporter: Venugopal Reddy K
>            Priority: Minor
>
> +*Issue-1:*+
> {color:#0747a6}*Context:*{color}
> For a string column with local dictionary enabled, a column page of
> {{`{color:#de350b}UnsafeFixLengthColumnPage{color}` }}with datatype `{color:#de350b}{{DataTypes.BYTE_ARRAY}}{color}` is created for `{color:#de350b}{{encodedPage}}{color}` along with regular `{color:#de350b}{{actualPage}}{color}` of `{color:#de350b}{{UnsafeVarLengthColumnPage}}{color}`. 
> We have `{color:#de350b}*{{capacity}}*{color}` field in the `{color:#de350b}{{UnsafeFixLengthColumnPage}}{color}`. And this field indicates the capacity of  allocated
> `{color:#de350b}{{memoryBlock}}{color}` for the page. `{{{color:#de350b}ensureMemory{color}()}}` method gets called while adding rows to check if  `{color:#de350b}{{totalLength + requestSize > capacity}}{color}` to allocate a new memoryBlock. If there is no room to add the next row, allocates a new block, copy the old context(prev rows) and free the old memoryBlock.
> {color:#0747a6} *Problem:*{color}
> While, `{color:#de350b}{{UnsafeFixLengthColumnPage}}{color}` with with datatype `{color:#de350b}{{DataTypes.BYTE_ARRAY}}{color}` is created for `{color:#de350b}{{encodedPage}}{color}`, we have not assigned the *`{color:#de350b}{{capacity}}{color}`* field with allocated memory block size. Hence, for each add row to tablePage, *ensureMemory() check always fails*, allocates a new column page memoryBlock, copy the old context(prev rows) and free the old memoryBlock. This *allocation of new memoryBlock and free of old memoryBlock happens for each row row addition* for the string columns with local dictionary.
>  
> +*Issue-2:*+
> {color:#0747a6}*Context:*{color}
> In`{color:#de350b}VarLengthColumnPageBase{color}`, we have a `{color:#de350b}rowOffset{color}` column page of  `{color:#de350b}UnsafeFixLengthColumnPage{color}` of datatype `{color:#de350b}INT{color}`
> to maintain the data offset to {color:#172b4d}each{color} row of variable length columns. This `{color:#de350b}rowOffset{color}` page allocates to be size of page. 
> {color:#0747a6} *Problem:*{color}
> {color:#0747a6}{color:#172b4d}If we have 10 rows in the page, we need 11 rows for its rowOffset page. Because we always keep 0 as offset to 1st row. So an additional row is required for rowOffset page[pasted code below to show the reference]. Otherwise, we ensureMemory() check always fails for the last row(10th row in this case) of data and allocates a new crowOffset page memoryBlock, copy the old context(prev rows) and free the old memoryBlock. This can happen for the string columns with local dictionary, direct dictionary columns, global disctionary columns.{color}**{color}
>  
> {code:java}
> public abstract class VarLengthColumnPageBase extends ColumnPage {
> ...
> @Override
> public void putBytes(int rowId, byte[] bytes) {
>  ...
>  if (rowId == 0) {
>  rowOffset.putInt(0, 0);
>  }
>  rowOffset.putInt(rowId + 1, rowOffset.getInt(rowId) + bytes.length);
>  putBytesAtRow(rowId, bytes);
>  totalLength += bytes.length;
> }
> ...
> }
>  
> {code}
>  

--
This message was sent by Atlassian Jira
(v8.3.4#803005)