On 2017-02-28 04:56:43 Alvaro Herrera wrote:
> Here's a small patch to make a BRIN page range unsummarized. This is
> useful if data has been deleted, and the heap pages are now used for
> completely different data.
Hi,
I tried to apply your patch and use it. Applying and "make check" were
successed.
However, I found that when calling brin_desummarize_range successively, an
assertion is failed. It seems to me that it occurs when desummarizing a revmap
page that is already desummarized.
The tried queries and their outputs are the followings:
$ CREATE SCHEMA test_sc;
CREATE SCHEMA
$ CREATE TABLE test_sc.test(a int);
CREATE TABLE
$ INSERT INTO test_sc.test SELECT s FROM generate_series(1, 10000) s;
INSERT 0 10000
$ CREATE INDEX idx_brin ON test_sc.test USING brin(a);
CREATE INDEX
$ SELECT brin_desummarize_range('test_sc.idx_brin', 1);
brin_desummarize_range
------------------------
(1 row)
$ SELECT brin_desummarize_range('test_sc.idx_brin', 1);
psql:check_brin_desum.sql:10: server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
psql:check_brin_desum.sql:10: connection to server was lost
Then, the server log is the following:
TRAP: FailedAssertion("!(!LWLockHeldByMe(((LWLock*) (&(buf)->content_lock))))",
File: "bufmgr.c", Line: 1714)
2017-03-22 15:06:12.842 JST [23107] LOG: server process (PID 23186) was
terminated by signal 6: Aborted
2017-03-22 15:06:12.842 JST [23107] DETAIL: Failed process was running: SELECT
brin_desummarize_range('test_sc.idx_brin', 1);
When assertion is failed, the following brinRevmapTerminate function is called.
Then, it tries to release revmap->rm_currBuf by ReleaseBuffer function and it
is failed.
+bool
+brinRevmapDesummarizeRange(Relation idxrel, BlockNumber heapBlk)
+{
...
+ if (!ItemPointerIsValid(iptr))
+ {
+ /* no index tuple: range not summarized, we're done */
+ brinRevmapTerminate(revmap);
+ return true;
+ }
--
Regards,
Eiji Seki
Fujitsu
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