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Posted to dev@parquet.apache.org by "Anthony Pessy (JIRA)" <ji...@apache.org> on 2019/06/18 12:08:00 UTC

[jira] [Comment Edited] (PARQUET-1602) PageIndex not working as suggested ?

    [ https://issues.apache.org/jira/browse/PARQUET-1602?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16866549#comment-16866549 ] 

Anthony Pessy edited comment on PARQUET-1602 at 6/18/19 12:07 PM:
------------------------------------------------------------------

For the following output (sorry for approximative indentation, lost during copy/paste):
{noformat}
row group 0:
column index for column url:
Boudary order: ASCENDING
                null count min                                                       max
page-0           0         http://materiais.(...)delos-de-curriculo https://api.quero(...)954874/toogle_like
page-1           0         https://api.quero(...)880/toogle_dislike https://api.quero(...)ior-online/encceja
page-2           0          https://api.quero(...)erior-online/todos https://api.quero(...)nte-em-saude/todos

 

offset index for column url:
offset   compressed size          first row index
page-0 4                  224274    0
page-1 224278        100168    20000
page-2 324446        67778      40000

column index for column content:
NONE
offset index for column content:
offset      compressed    size        first row index
page-0    392224         504412    0
page-1     896636       784246    125
page-2      1680882     641212   200

[...truncated...]

page-596               256651848            183162                 53100{noformat}
 

When looking for the url matching the 'max' of `page-0` ( `[https://api.quero(...)954874/toogle_like|https://api.quero%28...%29954874/toogle_like]`) I have in total 213 pages loaded (1 for url and 212 for content) (~230MB of data transferred).

 

Offsets for content:
{code:java}
page-212    98231687   206970   26750
page-213    98438657   501408   26850
{code}
 

It would imply that it loaded every page of content until until the matching row.

 

On a separate note when the tool says `[https://api.quero(...)954874/toogle_like|https://api.quero%28...%29954874/toogle_like]`, do you now if it's a display thing or actually truncated like that ? I set the index max length 512 when creating the file.

 

 

 

 


was (Author: panthony):
For the following output (sorry for approximative indentation, lost during copy/paste):
{noformat}
row group 0:
column index for column url:
Boudary order: ASCENDING
                null count min                                                       max
page-0           0         http://materiais.(...)delos-de-curriculo https://api.quero(...)954874/toogle_like
page-1           0         https://api.quero(...)880/toogle_dislike https://api.quero(...)ior-online/encceja
page-2           0          https://api.quero(...)erior-online/todos https://api.quero(...)nte-em-saude/todos

 

offset index for column url:
offset   compressed size          first row index
page-0 4                  224274    0
page-1 224278        100168    20000
page-2 324446        67778      40000

column index for column content:
NONE
offset index for column content:
offset      compressed    size        first row index
page-0    392224         504412    0
page-1     896636       784246    125
page-2      1680882     641212   200

[...truncated...]

page-596               256651848            183162                 53100{noformat}
 

When looking for the url matching the 'max' of `page-0` ( `[https://api.quero(...)954874/toogle_like|https://api.quero%28...%29954874/toogle_like]`) I have in total 213 pages loaded (1 for url and 212 for content) (~230MB of data transferred).

 

Offsets for content:

 

 
{code:java}
page-212    98231687   206970   26750
page-213    98438657   501408   26850
{code}
 

It would imply that it loaded every page of content until until the matching row.

 

 

On a separate note when the tool says `[https://api.quero(...)954874/toogle_like|https://api.quero%28...%29954874/toogle_like]`, do you now if it's a display thing or actually truncated like that ? I set the index max length 512 when creating the file.

 

 

 

 

> PageIndex not working as suggested ?
> ------------------------------------
>
>                 Key: PARQUET-1602
>                 URL: https://issues.apache.org/jira/browse/PARQUET-1602
>             Project: Parquet
>          Issue Type: Improvement
>          Components: parquet-mr
>    Affects Versions: 1.11.0
>            Reporter: Anthony Pessy
>            Priority: Major
>
> I have a schema such as:
>  
> ``` 
> {{schema message pages {}}
> {{  required binary url (STRING);}}
> {{  optional binary content (STRING);}}
> {{}}}
> ``` 
>  
> Where `url` is unique and ordered, the file is created in such a way that I have ~600 pages of `content` for 1 page of `url`.
>  
> From [https://github.com/apache/parquet-format/blob/master/PageIndex.md] I saw:
> > A single-row lookup in a rowgroup based on the sort column of that rowgroup will only read one data page per retrieved column.
>  
>  
> I was expecting `ParquetReader`  to find the matching row thanks to the `FilterPredicate`  on `url`, decoding only this column, then, using `offset index`, directly seek to the appropriate page for `content` and decode it.
>  
>  
> Instead, what I'm seeing, is that the reader fully reads & decode the ~600 pages of content (until it actually find the url).
>  
> Is there something I misunderstood or some step to ensure to make the reader only consume the necessary pages?
>  
>  
>  
>  



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