A key file is a small file with the list of keys, it's not supposed to be more than 1Mb, and if it is — it's considered invalid, that's what the error says.

May be it could be optimized by not reading the file at all in this case, but it's not the code path we need to optimize, so either behavior is fine.

as for 2. — did you try to pipe a >64K file? because the message says "read bytes: 65536, max key file size: 1048576 bytes", so max size is 1Mb.

did you try to pipe a >64K file?
sergYes, I tried piping a ~1MB file. But it reads only 64K bytes and then errors out.

okay. 64K is a default fifo buffer size. I'll do something about it, thanks.

pushed fixes for both 1 and 2

I'm closing testing after covering the following test cases,
1. Pipe valid key:value data
2. Multiple writes into a single pipe
3. Pipe key:value data without the mandatory key 1
4. Pipe key:value data exceeding max size of 1MB
5. Pipe with no data
6. Use a key not present in the piped data
7. Install with non-existing pipe
8. Install with already pipe by another program
9. CRATE TABLE/ALTER TABLE with valid encryption key
10. CRATE TABLE/ALTER TABLE with invalid encryption key

The test results are looking good. OK to push from QA.