> There is a hook "post_parse_analyze_hook" but I think it comes too
> late as it comes after the analyze step which is when Postgres looks
> up the schema information for every relation mentioned in the query.
> What you would need is a post_parse_hook which would work on the raw
> parse tree befo
On Sat, Feb 15, 2014 at 2:06 PM, David Beck wrote:
> - when the query arrives a smart rewrite would know 1) what tables are local
> 2) what tables need new catalog entries 3) what can be joined on the other
> side
> - the rewriter would potentially add SQL statements in the beginning of the
> q
2014.02.15. dátummal, 0:46 időpontban Greg Stark írta:
> On Fri, Feb 14, 2014 at 9:16 PM, David Beck wrote:
>> Another point I liked in mysql is the possibility to write info schema
>> plugins:
>> http://dev.mysql.com/doc/refman/5.1/en/writing-information-schema-plugins.html
>> Like a virtual
On Fri, Feb 14, 2014 at 9:16 PM, David Beck wrote:
> What inspired me is the scriptable query rewrite in
> http://dev.mysql.com/downloads/mysql-proxy/
> The hook I proposed would be a lot nicer in Postgres because the raw parsing
> is already done at this point while in mysql-proxy that has to b
Greg Stark writes:
> On Fri, Feb 14, 2014 at 9:16 PM, David Beck wrote:
>> Another point I liked in mysql is the possibility to write info schema
>> plugins:
>> http://dev.mysql.com/doc/refman/5.1/en/writing-information-schema-plugins.html
>> Like a virtual catalog. Is there anything similar in
On Fri, Feb 14, 2014 at 9:16 PM, David Beck wrote:
> Another point I liked in mysql is the possibility to write info schema
> plugins:
> http://dev.mysql.com/doc/refman/5.1/en/writing-information-schema-plugins.html
> Like a virtual catalog. Is there anything similar in Postgres?
The documentat
I think I’m gonna need to dig into the planner to fully understand your points.
Thank you for the insights. I was more into putting the knowledge of the legacy
system into the an extension and my codebase. Now I see better use of the
planner would help. Thank you.
What inspired me is the script
On Fri, Feb 14, 2014 at 2:28 PM, David Beck wrote:
> Why is that a bad idea of rewriting the query before it reaches
> transform/analyze (without ever accessing the catalog)?
>
> If that flexibility is acceptable to you, where would be the best place to
> put it in?
Well if there are two foreig
Let me rephrase this:
Let’s remove my motivations and use cases from this conversation….
Why is that a bad idea of rewriting the query before it reaches
transform/analyze (without ever accessing the catalog)?
If that flexibility is acceptable to you, where would be the best place to put
it in?
Thanks for the reply. There are two things I think I’ve been misunderstood:
1, the point is to do the rewrite without and before catalog access
2, I do want to push the join to the source and equally important pushing the
where conditions there
Best regards, David
2014.02.13. dátummal, 21:22 i
David Beck writes:
> I have table like data structures in the source system for the FDW I work on.
> These tables are sometimes too big and the source system is able to filter
> and join them with limitations, thus it is not optimal to transfer the data
> to Postgres.
> At the same time I want t
Thanks for the link.
I want flexibility. Here is a situation: my hook knows the size of tableA and
tableB on the legacy side. It should be able to decide wether to offload the
join/filter onto the legacy side or not. At the same time it can start
transferring the data to real Postgres tables in
See the discussion of Custom-Scan API.
https://commitfest.postgresql.org/action/patch_view?id=1282
I believe my third patch is what you really want to do...
> This rewritten query would be handled by the FDW table that I previously
> added to the catalog.
>
> The reason I want this new hook is t
Hello Hackers,
I work on a foreign data wrapper for a legacy system. I generally find the hook
system very useful and flexible way to extend Postgres.
The post parse analyze hook almost fits what I need, but I have a few use cases
where I would need to tap right into the parsed queries but befor
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