Thread

1. Re: no way in LargeObject API to detect short read?

   Paul M. Aoki <aoki@acm.org> — 2001-01-24T21:42:43Z

   Bruce Momjian <pgman@candle.pha.pa.us> writes:
   > Anyone able to fix this?
   
   here's a hack we've been using in-house (written by Jun Gabayan,
   <jgabayan@pahv.xerox.com>).
   
   you may not like the style but it's a stab at a solution.
   --
    Paul M. Aoki / Xerox Palo Alto Research Center / 3333 Coyote Hill Road
    aoki@acm.org / Computer Science Laboratory     / Palo Alto, CA 94304-1314
   
   Index: LargeObject.java
   ===================================================================
   RCS file: /project/placeless/cvsroot/placeless2/src/org/postgresql/largeobject/LargeObject.java,v
   retrieving revision 1.1
   retrieving revision 1.3
   diff -r1.1 -r1.3
   64c64,67
   <   
   ---
   > 
   >   private int pos = 0; //current position
   >   private int size = 0;
   > 
   85a89,90
   >     pos = tell();
   >     size = size();
   102a108
   >     if(fd == 0) return;
   105a112
   >     fd = 0;
   118a126,132
   >         // calculate available data to read to avoid reading pass the end
   >         // to avoid an exception
   >         pos = tell();
   >         int avail = size - pos;
   >         if(avail == 0) return null;
   >         if(avail < len) len = avail;
   >         try {
   123c137,141
   < 	
   ---
   >         }catch(SQLException se) {
   >           System.out.println("***LargeObject.read: Caught SQLException: " + se.getMessage());
   >           return null;
   >         }
   > 
   157c175
   <   public void read(byte buf[],int off,int len) throws SQLException
   ---
   >   public int read(byte buf[],int off,int len) throws SQLException
   159c177,180
   <     System.arraycopy(read(len),0,buf,off,len);
   ---
   >     byte mybuf[] = read(len);
   >     int sz = (mybuf != null) ? mybuf.length : -1; //must return -1 for end of data
   >     if(sz > 0) System.arraycopy(mybuf,0,buf,off,sz);
   >     return sz;
   
   

2. Re: no way in LargeObject API to detect short read?

   Bruce Momjian <pgman@candle.pha.pa.us> — 2001-01-25T00:04:03Z

   Paul, I need a context diff.  Thanks.
   
   > Bruce Momjian <pgman@candle.pha.pa.us> writes:
   > > Anyone able to fix this?
   > 
   > here's a hack we've been using in-house (written by Jun Gabayan,
   > <jgabayan@pahv.xerox.com>).
   > 
   > you may not like the style but it's a stab at a solution.
   > --
   >  Paul M. Aoki / Xerox Palo Alto Research Center / 3333 Coyote Hill Road
   >  aoki@acm.org / Computer Science Laboratory     / Palo Alto, CA 94304-1314
   > 
   > Index: LargeObject.java
   > ===================================================================
   > RCS file: /project/placeless/cvsroot/placeless2/src/org/postgresql/largeobject/LargeObject.java,v
   > retrieving revision 1.1
   > retrieving revision 1.3
   > diff -r1.1 -r1.3
   > 64c64,67
   > <   
   > ---
   > > 
   > >   private int pos = 0; //current position
   > >   private int size = 0;
   > > 
   > 85a89,90
   > >     pos = tell();
   > >     size = size();
   > 102a108
   > >     if(fd == 0) return;
   > 105a112
   > >     fd = 0;
   > 118a126,132
   > >         // calculate available data to read to avoid reading pass the end
   > >         // to avoid an exception
   > >         pos = tell();
   > >         int avail = size - pos;
   > >         if(avail == 0) return null;
   > >         if(avail < len) len = avail;
   > >         try {
   > 123c137,141
   > < 	
   > ---
   > >         }catch(SQLException se) {
   > >           System.out.println("***LargeObject.read: Caught SQLException: " + se.getMessage());
   > >           return null;
   > >         }
   > > 
   > 157c175
   > <   public void read(byte buf[],int off,int len) throws SQLException
   > ---
   > >   public int read(byte buf[],int off,int len) throws SQLException
   > 159c177,180
   > <     System.arraycopy(read(len),0,buf,off,len);
   > ---
   > >     byte mybuf[] = read(len);
   > >     int sz = (mybuf != null) ? mybuf.length : -1; //must return -1 for end of data
   > >     if(sz > 0) System.arraycopy(mybuf,0,buf,off,sz);
   > >     return sz;
   > 
   
   
   -- 
     Bruce Momjian                        |  http://candle.pha.pa.us
     pgman@candle.pha.pa.us               |  (610) 853-3000
     +  If your life is a hard drive,     |  830 Blythe Avenue
     +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026
   
   

3. Re: [JDBC] Re: no way in LargeObject API to detect short read?

   Peter Mount <peter@retep.org.uk> — 2001-01-26T09:31:13Z

   Hmmm, what's the performance issues with this? Is there going to be a problem 
   with very large LargeObject's?
   
   Quoting "Paul M. Aoki" <aoki@acm.org>:
   
   > Bruce Momjian <pgman@candle.pha.pa.us> writes:
   > > Anyone able to fix this?
   > 
   > here's a hack we've been using in-house (written by Jun Gabayan,
   > <jgabayan@pahv.xerox.com>).
   > 
   > you may not like the style but it's a stab at a solution.
   > --
   >  Paul M. Aoki / Xerox Palo Alto Research Center / 3333 Coyote Hill Road
   >  aoki@acm.org / Computer Science Laboratory     / Palo Alto, CA
   > 94304-1314
   > 
   > Index: LargeObject.java
   > ===================================================================
   > RCS file:
   > /project/placeless/cvsroot/placeless2/src/org/postgresql/largeobject/LargeObje
   ct.java,v
   > retrieving revision 1.1
   > retrieving revision 1.3
   > diff -r1.1 -r1.3
   > 64c64,67
   > <   
   > ---
   > > 
   > >   private int pos = 0; //current position
   > >   private int size = 0;
   > > 
   > 85a89,90
   > >     pos = tell();
   > >     size = size();
   > 102a108
   > >     if(fd == 0) return;
   > 105a112
   > >     fd = 0;
   > 118a126,132
   > >         // calculate available data to read to avoid reading pass the
   > end
   > >         // to avoid an exception
   > >         pos = tell();
   > >         int avail = size - pos;
   > >         if(avail == 0) return null;
   > >         if(avail < len) len = avail;
   > >         try {
   > 123c137,141
   > < 	
   > ---
   > >         }catch(SQLException se) {
   > >           System.out.println("***LargeObject.read: Caught
   > SQLException: " + se.getMessage());
   > >           return null;
   > >         }
   > > 
   > 157c175
   > <   public void read(byte buf[],int off,int len) throws SQLException
   > ---
   > >   public int read(byte buf[],int off,int len) throws SQLException
   > 159c177,180
   > <     System.arraycopy(read(len),0,buf,off,len);
   > ---
   > >     byte mybuf[] = read(len);
   > >     int sz = (mybuf != null) ? mybuf.length : -1; //must return -1 for
   > end of data
   > >     if(sz > 0) System.arraycopy(mybuf,0,buf,off,sz);
   > >     return sz;
   > 
   
   
   
   -- 
   Peter Mount peter@retep.org.uk
   PostgreSQL JDBC Driver: http://www.retep.org.uk/postgres/
   RetepPDF PDF library for Java: http://www.retep.org.uk/pdf/
   
   

4. Re: [BUGS] no way in LargeObject API to detect short read?

   Barry Lind <barry@xythos.com> — 2001-01-26T23:37:50Z

   Peter,
   
   Given the current implementation of size(), I don't think this is a good
   solution to the problem at hand.  Since size() is an expensive call
   (especially on large files), using it in this way wouldn't be a
   performant solution.  Using size() also requires additional round trips
   to the database to get this information.  There needs to be a better
   solution that doesn't require the additional overhead.
   
   thanks,
   --Barry
   
   Peter T Mount wrote:
   > 
   > Hmmm, what's the performance issues with this? Is there going to be a problem
   > with very large LargeObject's?
   > 
   > Quoting "Paul M. Aoki" <aoki@acm.org>:
   > 
   > > Bruce Momjian <pgman@candle.pha.pa.us> writes:
   > > > Anyone able to fix this?
   > >
   > > here's a hack we've been using in-house (written by Jun Gabayan,
   > > <jgabayan@pahv.xerox.com>).
   > >
   > > you may not like the style but it's a stab at a solution.
   > > --
   > >  Paul M. Aoki / Xerox Palo Alto Research Center / 3333 Coyote Hill Road
   > >  aoki@acm.org / Computer Science Laboratory     / Palo Alto, CA
   > > 94304-1314
   > >
   > > Index: LargeObject.java
   > > ===================================================================
   > > RCS file:
   > > /project/placeless/cvsroot/placeless2/src/org/postgresql/largeobject/LargeObje
   > ct.java,v
   > > retrieving revision 1.1
   > > retrieving revision 1.3
   > > diff -r1.1 -r1.3
   > > 64c64,67
   > > <
   > > ---
   > > >
   > > >   private int pos = 0; //current position
   > > >   private int size = 0;
   > > >
   > > 85a89,90
   > > >     pos = tell();
   > > >     size = size();
   > > 102a108
   > > >     if(fd == 0) return;
   > > 105a112
   > > >     fd = 0;
   > > 118a126,132
   > > >         // calculate available data to read to avoid reading pass the
   > > end
   > > >         // to avoid an exception
   > > >         pos = tell();
   > > >         int avail = size - pos;
   > > >         if(avail == 0) return null;
   > > >         if(avail < len) len = avail;
   > > >         try {
   > > 123c137,141
   > > <
   > > ---
   > > >         }catch(SQLException se) {
   > > >           System.out.println("***LargeObject.read: Caught
   > > SQLException: " + se.getMessage());
   > > >           return null;
   > > >         }
   > > >
   > > 157c175
   > > <   public void read(byte buf[],int off,int len) throws SQLException
   > > ---
   > > >   public int read(byte buf[],int off,int len) throws SQLException
   > > 159c177,180
   > > <     System.arraycopy(read(len),0,buf,off,len);
   > > ---
   > > >     byte mybuf[] = read(len);
   > > >     int sz = (mybuf != null) ? mybuf.length : -1; //must return -1 for
   > > end of data
   > > >     if(sz > 0) System.arraycopy(mybuf,0,buf,off,sz);
   > > >     return sz;
   > >
   > 
   > --
   > Peter Mount peter@retep.org.uk
   > PostgreSQL JDBC Driver: http://www.retep.org.uk/postgres/
   > RetepPDF PDF library for Java: http://www.retep.org.uk/pdf/
   
   

5. Re: [BUGS] no way in LargeObject API to detect short read?

   Peter Mount <peter@retep.org.uk> — 2001-01-27T17:01:24Z

   At 15:37 26/01/01 -0800, Barry Lind wrote:
   >Peter,
   >
   >Given the current implementation of size(), I don't think this is a good
   >solution to the problem at hand.  Since size() is an expensive call
   >(especially on large files), using it in this way wouldn't be a
   >performant solution.  Using size() also requires additional round trips
   >to the database to get this information.  There needs to be a better
   >solution that doesn't require the additional overhead.
   
   
   That's exactly what I was thinking of. Most of the largeobject API is based 
   on libpq hence where this came from. I don't think there is 
   anything  available elsewhere for getting the size.
   
   Yes, there needs to be a better way.
   
   Peter
   
   
   >thanks,
   >--Barry
   >
   >Peter T Mount wrote:
   > >
   > > Hmmm, what's the performance issues with this? Is there going to be a 
   > problem
   > > with very large LargeObject's?
   > >
   > > Quoting "Paul M. Aoki" <aoki@acm.org>:
   > >
   > > > Bruce Momjian <pgman@candle.pha.pa.us> writes:
   > > > > Anyone able to fix this?
   > > >
   > > > here's a hack we've been using in-house (written by Jun Gabayan,
   > > > <jgabayan@pahv.xerox.com>).
   > > >
   > > > you may not like the style but it's a stab at a solution.
   > > > --
   > > >  Paul M. Aoki / Xerox Palo Alto Research Center / 3333 Coyote Hill Road
   > > >  aoki@acm.org / Computer Science Laboratory     / Palo Alto, CA
   > > > 94304-1314
   > > >
   > > > Index: LargeObject.java
   > > > ===================================================================
   > > > RCS file:
   > > > 
   > /project/placeless/cvsroot/placeless2/src/org/postgresql/largeobject/LargeObje
   > > ct.java,v
   > > > retrieving revision 1.1
   > > > retrieving revision 1.3
   > > > diff -r1.1 -r1.3
   > > > 64c64,67
   > > > <
   > > > ---
   > > > >
   > > > >   private int pos = 0; //current position
   > > > >   private int size = 0;
   > > > >
   > > > 85a89,90
   > > > >     pos = tell();
   > > > >     size = size();
   > > > 102a108
   > > > >     if(fd == 0) return;
   > > > 105a112
   > > > >     fd = 0;
   > > > 118a126,132
   > > > >         // calculate available data to read to avoid reading pass the
   > > > end
   > > > >         // to avoid an exception
   > > > >         pos = tell();
   > > > >         int avail = size - pos;
   > > > >         if(avail == 0) return null;
   > > > >         if(avail < len) len = avail;
   > > > >         try {
   > > > 123c137,141
   > > > <
   > > > ---
   > > > >         }catch(SQLException se) {
   > > > >           System.out.println("***LargeObject.read: Caught
   > > > SQLException: " + se.getMessage());
   > > > >           return null;
   > > > >         }
   > > > >
   > > > 157c175
   > > > <   public void read(byte buf[],int off,int len) throws SQLException
   > > > ---
   > > > >   public int read(byte buf[],int off,int len) throws SQLException
   > > > 159c177,180
   > > > <     System.arraycopy(read(len),0,buf,off,len);
   > > > ---
   > > > >     byte mybuf[] = read(len);
   > > > >     int sz = (mybuf != null) ? mybuf.length : -1; //must return -1 for
   > > > end of data
   > > > >     if(sz > 0) System.arraycopy(mybuf,0,buf,off,sz);
   > > > >     return sz;
   > > >
   > >
   > > --
   > > Peter Mount peter@retep.org.uk
   > > PostgreSQL JDBC Driver: http://www.retep.org.uk/postgres/
   > > RetepPDF PDF library for Java: http://www.retep.org.uk/pdf/