Forgive me if this has been already discussed somewhere.

When a transaction aborts, it seems a BRIN index leaves summary data
which is not valid any more. Is this an expected behavior?  I guess
the answer is yes, because it does not affect correctness of a query
result, but I would like to make sure.

Second question is when the wrong summary data is gone? It seems
vacuum does not help. Do I have to recreate the index (or reindex)?

test=# begin;
BEGIN
test=# insert into t1 values(1000001);
INSERT 0 1
test=# SELECT * FROM brin_page_items(get_raw_page('brinidx', 2),'brinidx');
 itemoffset | blknum | attnum | allnulls | hasnulls | placeholder |        
value        
------------+--------+--------+----------+----------+-------------+---------------------
          1 |      0 |      1 | f        | f        | f           | {1 .. 28928}
          2 |    128 |      1 | f        | f        | f           | {28929 .. 
57856}
          3 |    256 |      1 | f        | f        | f           | {57857 .. 
86784}
[snip]
         34 |   4224 |      1 | f        | f        | f           | {954625 .. 
983552}
         35 |   4352 |      1 | f        | f        | f           | {983553 .. 
1000001}
(35 rows)

test=# abort;
ROLLBACK
test=# SELECT * FROM brin_page_items(get_raw_page('brinidx', 2),'brinidx');
 itemoffset | blknum | attnum | allnulls | hasnulls | placeholder |        
value        
------------+--------+--------+----------+----------+-------------+---------------------
          1 |      0 |      1 | f        | f        | f           | {1 .. 28928}
          2 |    128 |      1 | f        | f        | f           | {28929 .. 
57856}
          3 |    256 |      1 | f        | f        | f           | {57857 .. 
86784}
[snip]
         34 |   4224 |      1 | f        | f        | f           | {954625 .. 
983552}
         35 |   4352 |      1 | f        | f        | f           | {983553 .. 
1000001}
(35 rows)

test=# vacuum t1;
VACUUM
test=# SELECT * FROM brin_page_items(get_raw_page('brinidx', 2),'brinidx');
 itemoffset | blknum | attnum | allnulls | hasnulls | placeholder |        
value        
------------+--------+--------+----------+----------+-------------+---------------------
          1 |      0 |      1 | f        | f        | f           | {1 .. 28928}
          2 |    128 |      1 | f        | f        | f           | {28929 .. 
57856}
          3 |    256 |      1 | f        | f        | f           | {57857 .. 
86784}
[snip]
         33 |   4096 |      1 | f        | f        | f           | {925697 .. 
954624}
         34 |   4224 |      1 | f        | f        | f           | {954625 .. 
983552}
         35 |   4352 |      1 | f        | f        | f           | {983553 .. 
1000001}
(35 rows)

test=# select max(i) from t1;
   max   
---------
 1000000
(1 row)
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp


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