On 05/05/2018 12:13 PM, Adrian Klaver wrote:
On 05/05/2018 07:14 AM, Ron wrote:
Hi,
v9.6
We've got big databases where some of the tables are highly compressible, but some have many bytea fields containing PDF files.
Can you see a demonstrable difference?
Very much so. The ASCII hex representations of the PDF files are compressible, but take a
long time to compress. Uncompressed backups are 50% faster.
When the data format is custom, directory or tar, how feasible would a "--no-blob-compression" option be (where pg_dump just tells the zlib library to just Store tables with bytea columns, while compressing all other tables at the specified -Z level)?
In pg_dump blob refers to large objects:
https://www.postgresql.org/docs/10/static/app-pgdump.html
"
-b
--blobs
Include large objects in the dump. This is the default behavior except when --schema, --table, or --schema-only is specified. The -b switch is therefore only useful to add large objects to dumps where a specific schema or table has been requested. Note that blobs are considered data and therefore will be included when --data-only is used, but not when --schema-only is.
"
These are different critters then bytea.
Ok. I need the data in my backups anyway, so excluding them is 100% contrary to what I need.
--
Angular momentum makes the world go 'round.