Re: POC PATCH: copy from ... exceptions to: (was Re: VLDB Features) - Mailing list pgsql-hackers

From Andres Freund
Subject Re: POC PATCH: copy from ... exceptions to: (was Re: VLDB Features)
Date
Msg-id 20230205233723.xw5z5zmeyc57ezq3@alap3.anarazel.de
Whole thread Raw
In response to Re: POC PATCH: copy from ... exceptions to: (was Re: VLDB Features)  (Damir Belyalov <dam.bel07@gmail.com>)
Responses Re: POC PATCH: copy from ... exceptions to: (was Re: VLDB Features)  (Damir Belyalov <dam.bel07@gmail.com>)
List pgsql-hackers
H,

On 2023-02-03 13:27:24 +0300, Damir Belyalov wrote:
> @@ -625,6 +628,173 @@ CopyMultiInsertInfoStore(CopyMultiInsertInfo *miinfo, ResultRelInfo *rri,
>      miinfo->bufferedBytes += tuplen;
>  }
>  
> +/*
> + * Safely reads source data, converts to a tuple and fills tuple buffer.
> + * Skips some data in the case of failed conversion if data source for
> + * a next tuple can be surely read without a danger.
> + */
> +static bool
> +SafeCopying(CopyFromState cstate, ExprContext *econtext, TupleTableSlot *myslot)


> +    BeginInternalSubTransaction(NULL);
> +    CurrentResourceOwner = sfcstate->oldowner;

I don't think this is the right approach. Creating a subtransaction for
each row will cause substantial performance issues.

We now can call data type input functions without throwing errors, see
InputFunctionCallSafe(). Use that to avoid throwing an error instead of
catching it.

Greetings,

Andres Freund



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