From: Pramod Gopinath <Pramod.Gopinath_at_Sun.COM>
Date: Fri, 08 Sep 2006 17:22:58 -0700

Hi Andrei
     For Postgresql, issue 283 was reopened based on problems that users
were facing. Based on further testing found that there was an issue with
the current code. Hence I am resending the changed code for your review.

_/*Problem Description :*/_
Let me start by listing down the problems with the existing code :
1. If there were 2 entities, both defined with
   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
    public Long longKey;

   then for the first entity we properly associate the primary key field
to be a "SERIAL" and things work correctly.
But for the second entity, we treat it as as if GenerationType.AUTO was
specified i.e. we *do not* create the field as "SERIAL" and create a
table of the form
"SEQUENCE(SEQ_NAME, SEQ_COUNT)" and inserting a row with value of
"SEQ_GEN_SEQUENCE" from which we get the id field value at insert time.

2. If we have 2 entities defined as
@Entity
@Table(name = "Test1")
public class TestEntity1 {
   @Id
   @GeneratedValue(strategy = GenerationType.SEQUENCE, generator =
"TEST_SEQ_GENERATOR")
   @SequenceGenerator(name = "TEST_SEQ_GENERATOR", sequenceName =
"TEST_ID_SEQ")
    protected Long longKey;
}


@Entity
@Table(name = "Test2")
public class TestEntity2 {
    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator =
"TEST_SEQ_GENERATOR")
    @SequenceGenerator(name = "TEST_SEQ_GENERATOR", sequenceName =
"TEST_ID_SEQ")
     protected Long longKey;
}

then for one of the entites we would get the SERIAL field correctly
created with the implicit sequence name. But for the other entity we
create a default sequence table with a row inserted for the user
defined sequence "TEST_ID_SEQ"

_/*Solution :*/_
The 2 problem areas in the code are :
1. the if loop to get the value of "shouldVerifySequenceName"
     Cannot we just simplify this completely and just deal with one case
i.e. if sequence is found in the sequences hashmap and it is a
NativeSequence then continue with doing what we want to do.
     
2. the part where we do :
     removeSequence(currSequenceName);
    By removing the default sequence "SEQ_GEN_SEQUENCE" for the first
entity, subsequent entities would not find them and hence we end up
creating the table.

I have attached the latest code changes for your review.

Thanks
Pramod



Index: src/java/oracle/toplink/essentials/platform/database/PostgreSQLPlatform.java
===================================================================
RCS file: /cvs/glassfish/entity-persistence/src/java/oracle/toplink/essentials/platform/database/PostgreSQLPlatform.java,v
retrieving revision 1.8
diff -r1.8 PostgreSQLPlatform.java
415,428c415
< boolean shouldVerifySequenceName;
<
< boolean usesDefaultSequence = sequence == null || sequence instanceof DefaultSequence;
< if(usesDefaultSequence) {
< // is defaultSequence is a NativeSequence?
< if(isDefaultSequenceNative == null) {
< isDefaultSequenceNative = new Boolean(getDefaultSequence() instanceof NativeSequence);
< }
< shouldVerifySequenceName = isDefaultSequenceNative.booleanValue();
< } else {
< shouldVerifySequenceName = sequence instanceof NativeSequence;
< }
<
< if(shouldVerifySequenceName) {

---
>                 if (null != sequence && sequence instanceof NativeSequence) {
436,438c423,425
<                             removeSequence(currSequenceName);
<                             sequence.setName(seqName);
<                             addSequence(sequence);
---
>                             Sequence newSequence = (Sequence)sequence.clone();
>                             newSequence.setName(seqName);
>                             addSequence(newSequence);
445d431
<