Обсуждение: pg_basebackup: wal streaming can only be used in plain mode

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pg_basebackup: wal streaming can only be used in plain mode

От
Mitchell Bösecke
Дата:
Hi,

In regards to pg_basebackup, I want to use "--format=tar" (for the purpose of sending the backup to stdout) but when I also try to use "--xlog-method=stream" to include some WAL files (without worrying about the wal_keep_segment parameter on the server) it tells me "wal streaming can only be used in plain mode".

I can't find any documentation regarding this conflict between "--format=tar" and "--xlog-method=stream". Can anyone provide any insight into why this combination is forbidden, or where it might be documented? Are there plans to support this combination in the future?

Thanks for any help

--
Mitchell Bosecke, B.Sc.
Software Developer

FORCORP
#101, 11710 Kingsway NW
Edmonton , AB, T5G 0X5

(o) 587.410.4067
(f) 780.453.3986

Re: pg_basebackup: wal streaming can only be used in plain mode

От
John Scalia
Дата:
Mitchell,

If you look in the documentation, you'll see that the streaming mode requires a second replication connection. So, how would you integrate two separate channels into one tar input? Also, as the stream and backup aren't synchronized, there wouldn't be any way to isolate those in a tarball. True, they don't explicitly call this out, but if you think about it only the -X f mode (fetch) makes any sense. This is why I always use the fetch mode when writing to tar.

FWIW,
Jay

On 8/4/2015 6:09 PM, Mitchell Bösecke wrote:
Hi,

In regards to pg_basebackup, I want to use "--format=tar" (for the purpose of sending the backup to stdout) but when I also try to use "--xlog-method=stream" to include some WAL files (without worrying about the wal_keep_segment parameter on the server) it tells me "wal streaming can only be used in plain mode".

I can't find any documentation regarding this conflict between "--format=tar" and "--xlog-method=stream". Can anyone provide any insight into why this combination is forbidden, or where it might be documented? Are there plans to support this combination in the future?

Thanks for any help

--
Mitchell Bosecke, B.Sc.
Software Developer

FORCORP
#101, 11710 Kingsway NW
Edmonton , AB, T5G 0X5

(o) 587.410.4067
(f) 780.453.3986