[Exist-open] streaming results

[Eduard Drenth]

Dear all,

I am trying to stream the results of an xquery script, testing with

curl http://localhost:8080/exist/rest/db/apps/tdb/test.xq

But the script seems to first build the response and after that starts outputing.

Should I use response:stream? Do I need saxonica EE?

Eduard Drenth, Software Architekt

***@fryske-akademy.nl

Doelestrjitte 8
8911 DX Ljouwert
[phone]

gpg: https://sks-keyservers.net/pks/lookup?op=get&search=0x065EF82A1E02CC43

[Wolfgang Meier]

> But the script seems to first build the response and after that starts outputing.

Except for those calling response:streams explicitly, queries will always build the response before sending out results.

> Should I use response:stream? Do I need saxonica EE?

Saxon is not used for XQuery processing in eXist.

Wolfgang

[Eduard Drenth]

ok...

I tested with this script:

xquery version "3.1";

declare namespace response = "http://exist-db.org/xquery/response";

response:stream(
for $s in //*[not(*)]
return $s,
""
)

works, but it doesn't start outputing any sooner compared to this:

xquery version "3.1";

declare namespace response = "http://exist-db.org/xquery/response";

for $s in //*[not(*)]
return $s

and when I do this, I only see the first element after a long time:

xquery version "3.1";

declare namespace response = "http://exist-db.org/xquery/response";

for $s in //*[not(*)]
return response:stream($s, "")

Is there a way to realy stream these results?

Eduard Drenth, Software Architekt

***@fryske-akademy.nl

Doelestrjitte 8
8911 DX Ljouwert
[phone]

gpg: https://sks-keyservers.net/pks/lookup?op=get&search=0x065EF82A1E02CC43

________________________________________
From: Wolfgang Meier <***@exist-db.org>
Sent: Wednesday, June 7, 2017 3:25 PM
To: Eduard Drenth
Cc: exist-***@lists.sourceforge.net
Subject: Re: [Exist-open] streaming results

> But the script seems to first build the response and after that starts outputing.

Except for those calling response:streams explicitly, queries will always build the response before sending out results.

> Should I use response:stream? Do I need saxonica EE?

Saxon is not used for XQuery processing in eXist.

Wolfgang

[Eduard Drenth]

If I look here https://github.com/eXist-db/exist/blob/develop/src/org/exist/xquery/functions/response/Stream.java

it looks like Stream#eval can be / will be called only once with all output to be streamed.

It would be nice to be able to repeatedly call a function that streams for intermediary results. Perhaps not so simple though.

And perhaps I am mistaking....

Bye

Eduard Drenth, Software Architekt

***@fryske-akademy.nl

Doelestrjitte 8
8911 DX Ljouwert
[phone]

gpg: https://sks-keyservers.net/pks/lookup?op=get&search=0x065EF82A1E02CC43

________________________________________
From: Eduard Drenth <***@fryske-akademy.nl>
Sent: Wednesday, June 7, 2017 4:36 PM
To: Wolfgang Meier
Cc: exist-***@lists.sourceforge.net
Subject: Re: [Exist-open] streaming results

ok...

I tested with this script:

xquery version "3.1";

declare namespace response = "http://exist-db.org/xquery/response";

response:stream(
for $s in //*[not(*)]
return $s,
""
)

works, but it doesn't start outputing any sooner compared to this:

xquery version "3.1";

declare namespace response = "http://exist-db.org/xquery/response";

for $s in //*[not(*)]
return $s

and when I do this, I only see the first element after a long time:

xquery version "3.1";

declare namespace response = "http://exist-db.org/xquery/response";

for $s in //*[not(*)]
return response:stream($s, "")

Is there a way to realy stream these results?

Eduard Drenth, Software Architekt

***@fryske-akademy.nl

Doelestrjitte 8
8911 DX Ljouwert
[phone]

gpg: https://sks-keyservers.net/pks/lookup?op=get&search=0x065EF82A1E02CC43

________________________________________
From: Wolfgang Meier <***@exist-db.org>
Sent: Wednesday, June 7, 2017 3:25 PM
To: Eduard Drenth
Cc: exist-***@lists.sourceforge.net
Subject: Re: [Exist-open] streaming results

> But the script seems to first build the response and after that starts outputing.

Except for those calling response:streams explicitly, queries will always build the response before sending out results.

> Should I use response:stream? Do I need saxonica EE?

Saxon is not used for XQuery processing in eXist.

Wolfgang

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