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help / color / mirror / Atom feedFrom: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: Surafel Temesgen <surafel3000@gmail.com>
Cc: Adam Berlin <berlin.ab@gmail.com>
Cc: pgsql-hackers@lists.postgresql.org
Subject: Re: COPY FROM WHEN condition
Date: Tue, 4 Dec 2018 06:44:18 -0300
Message-ID: <20181204094418.wpr6mxrtsuxb5mlq@alvherre.pgsql> (raw)
In-Reply-To: <194e2225-b186-9325-0cd1-9a5b09d28251@2ndquadrant.com>
After reading this thread, I think I like WHERE better than FILTER.
Tally:
WHERE: Adam Berlin, Lim Myungkyu, Dean Rasheed, yours truly
FILTER: Tomas Vondra, Surafel Temesgen
Couldn't find others expressing an opinion in this regard.
On 2018-Nov-30, Tomas Vondra wrote:
> I think it should be enough just to switch to CIM_SINGLE and increment the
> command counter after each inserted row.
Do we apply command counter increment per row with some other COPY
option? Per-row CCI makes me a bit uncomfortable because with you'd get
in trouble with a large copy. I think it's particularly nasty here,
precisely because you may want to filter out some rows of a very large
file, and the CCI may prevent that from working.
I'm not convinced by the example case of reading how many tuples you've
imported so far in the WHERE/WHEN/FILTER clause each time (that'd become
incrementally slower as it progresses).
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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Cc: alvherre@2ndquadrant.com, tomas.vondra@2ndquadrant.com, surafel3000@gmail.com, berlin.ab@gmail.com, pgsql-hackers@lists.postgresql.org
Subject: Re: COPY FROM WHEN condition
In-Reply-To: <20181204094418.wpr6mxrtsuxb5mlq@alvherre.pgsql>
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