On 5/26/2010 10:04 AM, Greg Stark wrote:
On Sun, May 23, 2010 at 9:21 PM, Jan Wieck <janwi...@yahoo.com> wrote:
Each record of the Transaction Commit Info consists of
txid xci_transaction_id
timestamptz xci_begin_timestamp
timestamptz xci_commit_timestamp
int64 xci_total_rowcount
So I think you're going about this backward
Instead of discussing implementation I think you should start with the
API the replication system needs. In particular I'm not sure you
really want a server-side query at all. I'm wondering if you wouldn't
be better off with a public machine-parsable text format version of
the WAL. Ie, at the same time as writing out all the nitty gritty to
the binary wal we would write out a summary of public data to an xml
version containing just parts of the data stream that we can promise
won't change, such as transaction id, lsn, timestamp.
Since the actual row level change information and other event data is
found inside of regular tables, identified by TXID and sequence number,
I am pretty sure I want that data in a server-side query. What you are
proposing is to read the xid's and timestamps with an external process,
that now forcibly needs to reside on the DB server itself (neither
Londiste nor Slony have that requirement as of today), then bring it
back into the DB at least inside the WHERE clause of a query.
Jan
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liberty nor security. -- Benjamin Franklin
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