Re: BYTEA
"if you only work with small-ish binary data, yes - BYTEA does the job."
--The goal is to save/retrieve the user's photos (JPEG, TIFF, GIF) and PDF files. The size of each file is less than
5 MB. For such purpose, is BYTEA ok? If not, then how about 1 MB each?
"whole byte-array is kept in memory, both in the JAVA-app and in PG"
--I believe in Java the GarbageCollector will clean it up (?). "Who" will then clean up the Pg side?
"whole byte-array is kept in memory, both in the JAVA-app and in PG"
--Does that mean for the OID, byte-array is NOT kept in memory (of JAVA-app or PG)? If so, where is it kept? And how they are got cleaned up?
Thanks
Eugene
On Monday, January 18, 2016 5:07 AM, Andreas Joseph Krogh <andreas@visena.com> wrote:
På søndag 17. januar 2016 kl. 23:13:09, skrev Thomas Kellerer <spam_eater@gmx.net>:
Andreas Joseph Krogh schrieb am 17.01.2016 um 23:09:
> > Do I really *Need to escape/encode binary data before sending to DB
> > then do the reverse after retrieving the data?*
> > *
> > *
> > If so, what (*Java*) codes should I use to achieve this goal (I am using
> > the Java to interface with the DB)?
>
> https://jdbc.postgresql.org/documentation/94/binary-data.html
>
> Save yourself the trouble and don't go this route. Use https://github.com/impossibl/pgjdbc-ng instead.
Can you elaborate?
Using the "official" JDBC driver with bytea column works just fine for me.
Depends on what "works" is.
Using BLOBs (that is SQL-BLOB, not *ps.setBinaryStream etc.) with ps.setBlob/rs.getBlob and Connection.createBlob certainly doesn't work using the official driver. 
https://github.com/pgjdbc/pgjdbc/blob/master/pgjdbc/src/main/java/org/postgresql/jdbc/PgConnection.java#L1284-L1287
public Blob createBlob() throws SQLException { checkClosed(); throw org.postgresql.Driver.notImplemented(this.getClass(), "createBlob()"); }AFAIU this thread is about working with LARGE OBJECTS, not only binary data.
Also, using BYTEA with LARGE objects (not just binary data) quickly leads to OutOfMemoryError. Which is why I recommend using pgjdbc-ng and real BLOBs (using OID) instead. It is true that get/setBinaryStream "works", in essence that it appears to do the jobb. The problem is that despite using get/setBinaryStream with BYTEA appears to use streams, it doesn't, and the whole byte-array is kept in memory, both in the JAVA-app and in PG. The only way to work with real streams all the way is using OID, not BYTEA.But, of course, if you only work with small-ish binary data, yes - BYTEA does the job.
--
Andreas Joseph Krogh
CTO / Partner - Visena AS
Mobile: +47 909 56 963
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