Re: Add LZ4 compression in pg_dump - Mailing list pgsql-hackers

From Tomas Vondra
Subject Re: Add LZ4 compression in pg_dump
Date
Msg-id c75cf5ba-6cf8-a7eb-c9eb-87f7a56493c0@enterprisedb.com
Whole thread Raw
In response to Re: Add LZ4 compression in pg_dump  (Justin Pryzby <pryzby@telsasoft.com>)
Responses Re: Add LZ4 compression in pg_dump
Re: Add LZ4 compression in pg_dump
List pgsql-hackers

On 2/25/23 15:05, Justin Pryzby wrote:
> On Fri, Feb 24, 2023 at 11:02:14PM -0600, Justin Pryzby wrote:
>> I have some fixes (attached) and questions while polishing the patch for
>> zstd compression.  The fixes are small and could be integrated with the
>> patch for zstd, but could be applied independently.
> 
> One more - WriteDataToArchiveGzip() says:
> 
> +       if (cs->compression_spec.level == 0)
> +           pg_fatal("requested to compress the archive yet no level was specified");
> 
> That was added at e9960732a.  
> 
> But if you specify gzip:0, the compression level is already enforced by
> validate_compress_specification(), before hitting gzip.c:
> 
> | pg_dump: error: invalid compression specification: compression algorithm "gzip" expects a compression level between
1and 9 (default at -1)
 
> 
> 5e73a6048 intended that to work as before, and you *can* specify -Z0:
> 
>     The change is backward-compatible, hence specifying only an integer
>     leads to no compression for a level of 0 and gzip compression when the
>     level is greater than 0.
> 
>     $ time ./src/bin/pg_dump/pg_dump -h /tmp regression -t int8_tbl -Fp --compress 0 |file -
>     /dev/stdin: ASCII text
> 

FWIW I agree we should make this backwards-compatible - accept "0" and
treat it as no compression.

Georgios, can you prepare a patch doing that?


regards
-- 
Tomas Vondra
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company



pgsql-hackers by date:

Previous
From: Tomas Vondra
Date:
Subject: Re: Add LZ4 compression in pg_dump
Next
From: vignesh C
Date:
Subject: Re: Time delayed LR (WAS Re: logical replication restrictions)