On 2/20/19 3:04 PM, Tom Lane wrote: [snip]
Well, the entire tuple would be 25600 bytes plus some overhead, which cannot fit on a Postgres page (8K, unless the OP changed compile options without mentioning it). So something has to be done to make it fit, and that something is going to be toasting any fields that can be toasted. From memory, our threshold for trying to make tuples narrower is only a quarter-page anyway, so that the toaster will be trying to get this down to 2K if it can. That's certainly going to involve compressing every field, and I wouldn't be surprised if a lot of them get shoved out-of-line too. The OP might care to read https://www.postgresql.org/docs/current/storage-toast.html
Based on that and https://www.postgresql.org/docs/9.6/sql-altertable.html should I think about doing a SET STORAGE=EXTERNAL on columns with PDF and compressed TIFF data?
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