Re: [HACKERS] logical decoding of two-phase transactions

Hi,

I think the difference between abort and abort prepared should be
explained better (I am not quite sure I get it myself).

> + The required <function>abort_cb</function> callback is called whenever

Also, why is this one required when all the 2pc stuff is optional?

> +static void
> +DecodePrepare(LogicalDecodingContext *ctx, XLogRecordBuffer *buf,
> + xl_xact_parsed_prepare * parsed)
> +{
> + XLogRecPtr origin_lsn = parsed->origin_lsn;
> + TimestampTz commit_time = parsed->origin_timestamp;
> + XLogRecPtr origin_id = XLogRecGetOrigin(buf->record);
> + TransactionId xid = parsed->twophase_xid;
> + bool skip;
> +
> + Assert(parsed->dbId != InvalidOid);
> + Assert(TransactionIdIsValid(parsed->twophase_xid));
> +
> + /* Whether or not this PREPARE needs to be skipped. */
> + skip = DecodeEndOfTxn(ctx, buf, parsed, xid);
> +
> + FinalizeTxnDecoding(ctx, buf, parsed, xid, skip);

Given that DecodeEndOfTxn calls SnapBuildCommitTxn, won't this make the
catalog changes done by prepared transaction visible to other
transactions (which is undesirable as they should only be visible after
it's committed) ?

> + if (unlikely(TransactionIdIsValid(CheckXidAlive) &&
> + !(IsCatalogRelation(scan->rs_rd) ||
> + RelationIsUsedAsCatalogTable(scan->rs_rd))))
> + ereport(ERROR,
> + (errcode(ERRCODE_INVALID_TRANSACTION_STATE),
> + errmsg("improper heap_getnext call")));
> +
I think we should log the relation oid as well so that plugin developers
have easier time debugging this (for all variants of this).

--
Petr Jelinek http://www.2ndQuadrant.com/
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