RE: Simplify code building the LR conflict messages - Mailing list pgsql-hackers

Dear Amit, Shveta,

> >
> > 1)
> > DETAIL:  Could not apply remote row (20, 10).
> > DETAIL:  Could not apply remote row (40, 200) by using replica
> > identity (i)=(20).
> >
> > We generally "apply" in terms of insert, update, delete etc and not
> > rows. Do you think we shall have:
> > 'Could not apply remote change (20, 10)..'
> >
> > The most informative will be to say below, but since operation-type is
> > already mentioned in Context, mentioning it here might not be needed.
> > So we can say 'remote change'.
> >
> > DETAIL: Could not apply remote INSERT for row (30, 10).
> > DETAIL: Could not apply remote UPDATE for row (40, 200) using replica
> > identity (i)=(20).
> >
> 
> IIRC, the operation is already displayed in the context message. Here,
> we can say: DETAIL: Could not apply remote change using replica
> identity (i)=(20): remote row (40, 200).

Thanks for suggestions. I updated accordingly. Also, I found that local slot won't
be available in case of update_deleted, thus I removed from the code.
Current concern is that {update|delete}_origin_differ still construct the message
because there are three printable info. Can you suggest if you know better approaches?


In below I want to show some examples.

Case 1: multiple_unique_conflicts with UPDATE
HEAD:
DETAIL:  Key already exists in unique index "foo_pkey", modified locally in transaction 789 at ...
        Key (a)=(6); existing local row (6, 6, 6); remote row (6, 7, 8); replica identity (a)=(5).
        Key already exists in unique index "foo_b_key", modified locally in transaction 789 at ...
        Key (b)=(7); existing local row (7, 7, 7); remote row (6, 7, 8); replica identity (a)=(5).
        Key already exists in unique index "foo_c_key", modified locally in transaction 789 at ...
        Key (c)=(8); existing local row (8, 8, 8); remote row (6, 7, 8); replica identity (a)=(5).

V1:
DETAIL:  Could not apply remote row (6, 7, 8) by using replica identity (a)=(5).
        Key (a)=(6) already exists in unique index "foo_pkey", modified locally in transaction 790 at ...: local row
(6,6, 6).
 
        Key (b)=(7) already exists in unique index "foo_b_key", modified locally in transaction 790 at ...: local row
(7,7, 7).
 
        Key (c)=(8) already exists in unique index "foo_c_key", modified locally in transaction 790 at ...: local row
(8,8, 8).
 

V2:
DETAIL:  Could not apply remote change by using replica identity (a)=(5): remote row (6, 7, 8).
        Key (a)=(6) already exists in unique index "foo_pkey", modified locally in transaction 788 at ...: local row
(6,6, 6).
 
        Key (b)=(7) already exists in unique index "foo_b_key", modified locally in transaction 788 at ...: local row
(7,7, 7).
 
        Key (c)=(8) already exists in unique index "foo_c_key", modified locally in transaction 788 at ...: local row
(8,8, 8).
 

Case 2: update_origin_differs
HEAD:
DETAIL:  Updating the row that was modified locally in transaction 790 at ...
        Existing local row (5, 5, 5); remote row (6, 7, 8); replica identity (a)=(5).

V1:
DETAIL:  Remote row (6, 7, 8) was applied but previously modified by different origin.
        Local row (5, 5, 5) detected by replica identity (a)=(5) is being updated, but it was previously modified
locallyin transaction 790 at ....
 

V2:
DETAIL:  Updating the row that was modified locally in transaction 790 at ...: local row (5, 5, 5), remote row (6, 7,
8),replica identity (a)=(5).
 

Case 3: delete_origin_differs with huge column
HEAD:
DETAIL:  Deleting the row that was modified locally in transaction 795 at ...
        Existing local row (1, testtesttesttesttesttesttesttesttesttesttesttesttesttesttesttest...); replica identity
(id)=(1).

V1:
DETAIL:  Local row (1, testtesttesttesttesttesttesttesttesttesttesttesttesttesttesttest...) detected by replica
identity(id)=(1) is being deleted, but it was previously modified locally in transaction 797 at ....
 

V2:
DETAIL:  Deleting the row that was modified locally in transaction 807 at ...: local row (1,
testtesttesttesttesttesttesttesttesttesttesttesttesttesttesttest...),replica identity (id)=(1).
 

Case 4: update_deleted
HEAD:
DETAIL:  The row to be updated was deleted locally in transaction 789 at ...
        Remote row (6, 7, 8); replica identity (a)=(5).

V1:
DETAIL:  Could not find remote row (6, 7, 8) by using replica identity (a)=(5).
        Local row was previously deleted locally in transaction 795 at ....

V2:
DETAIL:  Could not find the row by using replica identity (a)=(5): remote row (6, 7, 8).
        The row to be updated was deleted locally in transaction 789 at ....

Best regards,
Hayato Kuroda
FUJITSU LIMITED