sqlite as 'streaming mode' query engine?

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sqlite as 'streaming mode' query engine?

Nelson, Erik - 2
Sqlite aggregation functions receive one call for each row in the underlying results set.  Has anyone on the list done a virtual table that's a based on a stream?

Something conceptually along the lines of

Insert row a
Insert row b
begin aggregation on rows a, b
insert row c
insert row d
update aggregation with rows c, d
...
finish aggregation when the stream of rows ends


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Re: [EXTERNAL] sqlite as 'streaming mode' query engine?

Hick Gunter
If your stream mode virtual table stalls in it's xNext method until the next row from the stream is available (or the stream is closed, in which case it needs to set an EOF flag for the xEof method to return), then each row will be aggregated as it becomes available. The result will not be available until after the stream is closed.

Receive row a
Aggregate row a
Receive row b
Aggregate row b
...
Stream ends
xEof returns true
result row(s) returned

If your stream is not repeatable, be sure to make it the primary table in any join, i.e. SELECT ... FROM <stream> CROSS JOIN ...

-----Urspr√ľngliche Nachricht-----
Von: sqlite-users [mailto:[hidden email]] Im Auftrag von Nelson, Erik - 2
Gesendet: Donnerstag, 25. Jänner 2018 20:03
An: SQLite mailing list <[hidden email]>
Betreff: [EXTERNAL] [sqlite] sqlite as 'streaming mode' query engine?

Sqlite aggregation functions receive one call for each row in the underlying results set.  Has anyone on the list done a virtual table that's a based on a stream?

Something conceptually along the lines of

Insert row a
Insert row b
begin aggregation on rows a, b
insert row c
insert row d
update aggregation with rows c, d
...
finish aggregation when the stream of rows ends


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This message, and any attachments, is for the intended recipient(s) only, may contain information that is privileged, confidential and/or proprietary and subject to important terms and conditions available at http://www.bankofamerica.com/emaildisclaimer.   If you are not the intended recipient, please delete this message.
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 Gunter Hick | Software Engineer | Scientific Games International GmbH | Klitschgasse 2-4, A-1130 Vienna | FN 157284 a, HG Wien, DVR: 0430013 | (O) +43 1 80100 - 0

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