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POHow come PostgreSQL 9.2.1 can store Large Object bigger than 2GB?
 

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  1. POHow come PostgreSQL 9.2.1 can store Large Object bigger than 2GB?
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    <p>I am totally new to PostgreSQL and database, and trying to do some tests about the large object.</p> <p>I just found that 8GB file could be saved to Postgres.</p> <p>However the document says the max for large object (<code>pg_largeobject</code> storage) is 2GB.</p> <p><a href="http://www.postgresql.org/docs/9.2/static/lo-intro.html" rel="nofollow">http://www.postgresql.org/docs/9.2/static/lo-intro.html</a></p> <p>Am I missing something here?</p> <p>Select <code>version()</code> shows:</p> <blockquote> <p>PostgreSQL 9.2.1 on x86_64-unknow-linux-gnu, compiled by gcc (GCC) 4.4.6 20120305 (Red Hat 4.4.6-4), 64-bit</p> </blockquote> <p>here is my code in case you are interested:</p> <pre><code>private long insertLargeObject(UsSqlSession session, FileEntity fileEntity) throws SQLException, FileNotFoundException, IOException{ LargeObjectManager lobj = getLargeObjectAPI(session); long oid = lobj.createLO(); LargeObject obj = lobj.open(oid, LargeObjectManager.WRITE); try(FileInputStream fis = new FileInputStream(fileEntity.getFile())){ int bufSize = 0x8FFFFFF; byte buf[] = new byte[bufSize]; int s = 0; int tl = 0; while( (s = fis.read(buf, 0, bufSize)) &gt; 0 ) { obj.write(buf, 0, s); tl += s; } } obj.close(); return oid; } </code></pre> <p><strong>UPDATE:</strong></p> <p>The size of the <code>pg_largeobject</code> is 11GB, and <code>pg_largeobject_metadata</code> says there is one line which means only one large object exists. </p> <pre><code>select sum(length(lo.data)) from pg_largeobject lo where lo.loid=1497980; </code></pre> <p>returns <code>4378853347</code>. </p> <p><strong>UPDATE:</strong></p> <pre><code>public File findLargeObject(UsSqlSession session, long oid) throws SQLException, FileNotFoundException, IOException{ LargeObjectManager lobj = getLargeObjectAPI(session); LargeObject obj = lobj.open(oid, LargeObjectManager.READ); int bufSize = 0x8FFFFFF; byte buf[] = new byte[bufSize]; int s = 0; int tl=0; File file = new File("e:/target-file"); try(FileOutputStream output = new FileOutputStream(file)){ while( (s = obj.read(buf, 0, bufSize)) &gt; 0 ){ output.write(buf, 0, s); tl += s; } output.flush(); } obj.close(); return file; } </code></pre>
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    1. COI'm curious about this myself. Could you try something from [this answer](http://stackoverflow.com/questions/10169309/get-size-of-large-object-in-postgresql-query) to check if it actually is 8 GB on the server side, just to be sure?
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    2. COYeah... if you're on 9.2 I'm not convinced the object is really the size you think, since all sizes are 32-bit signed integers. A 64-bit integer API for large objects is coming; I think it's in 9.3 but would need to double-check. **+1 thanks for including a proper version and the code in question**.
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      1. POHow come PostgreSQL 9.2.1 can store Large Object bigger than 2GB?
      1. USCraig Ringer
    3. CO@jpmc26 The size of the pg_large_object is 11GB, and pg_largeobject_metadata says there is one line.
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