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Posted to dev@phoenix.apache.org by "Lars Hofhansl (JIRA)" <ji...@apache.org> on 2016/02/21 21:13:18 UTC
[jira] [Updated] (PHOENIX-2702) Show estimate rows and bytes
touched for explain plan.
[ https://issues.apache.org/jira/browse/PHOENIX-2702?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Lars Hofhansl updated PHOENIX-2702:
-----------------------------------
Description:
We can already estimate the size of a table (both rows and uncompressed bytes) with q query like this:
{code}
SELECT physical_name AS table_name, SUM(guide_posts_row_count) AS est_rows, SUM(guide_posts_width) AS est_size from SYSTEM.STATS GROUP BY physical_name;
{code}
During the planning phase we have more information, though. So we can report the actual numbers for a query during an explain since we have that info there anyway (we filtered the guidepost already with the key info provided in the query).
I might whip up a quick patch for this.
(Could also go further and add a est_count, est_size UDF for this, but that would be a bit harder to get hooked up at the right places, I think, and the meaning would be ambiguous)
was:
We can already estimate the size of a table (both rows and uncompressed bytes) with q query like this:
{code}
SELECT physical_name AS table_name, SUM(guide_posts_row_count) AS est_rows, SUM(guilde_posts_width) AS est_size from SYSTEM.STATS GROUP BY physical_name;
{code}
During the planning phase we have more information, though. So we can report the actual numbers for a query during an explain since we have that info there anyway (we filtered the guidepost already with the key info provided in the query).
I might whip up a quick patch for this.
(Could also go further and add a est_count, est_size UDF for this, but that would be a bit harder to get hooked up at the right places, I think, and the meaning would be ambiguous)
> Show estimate rows and bytes touched for explain plan.
> ------------------------------------------------------
>
> Key: PHOENIX-2702
> URL: https://issues.apache.org/jira/browse/PHOENIX-2702
> Project: Phoenix
> Issue Type: Bug
> Reporter: Lars Hofhansl
>
> We can already estimate the size of a table (both rows and uncompressed bytes) with q query like this:
> {code}
> SELECT physical_name AS table_name, SUM(guide_posts_row_count) AS est_rows, SUM(guide_posts_width) AS est_size from SYSTEM.STATS GROUP BY physical_name;
> {code}
> During the planning phase we have more information, though. So we can report the actual numbers for a query during an explain since we have that info there anyway (we filtered the guidepost already with the key info provided in the query).
> I might whip up a quick patch for this.
> (Could also go further and add a est_count, est_size UDF for this, but that would be a bit harder to get hooked up at the right places, I think, and the meaning would be ambiguous)
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