FileDescriptor.sync() line: not available [native method]
Thomas,
I am tracking a problem that is really vexing. We pre-allocated
sequences a lot in our application, using the idiom:
"select nextval('SEQ') from system_range(1, 100)";
a LOT, usually around 10000 at a clip. When I test this for speed in
its own transaction, nothing else going on in the db, I get around
400k ids/sec generated -- nice.
However, I am seeing a slowdown when I do this in a transaction that
already has other updates to the database; sequence generation that
took a fraction of a second previously now takes 15 seconds.
Note that as of 1.1.109, this was fast as goose grease. ;-)
In the debugger, the stack trace *always* looks like the one I pasted
here.
Any ideas? Did something change in the lock handling for sequences
such that sequence generation is not cheap and fast anymore?
I'll try to put together a test case that shows it but I am on a plane
tomorrow early, so.
I'd hate to devolve to 1.1.109 or so to fix this.
The trace below is from 1.2.131.
Chris
FileObjectDisk.sync() line: 28
FileStore.sync() line: 453 [local variables unavailable]
PageStore.writeVariableHeader() line: 664
PageStore.setLogFirstPage(int, int, int) line: 660
PageLog.removeUntil(int) line: 669
PageStore.switchLog() line: 564
PageStore.checkpoint() line: 340
PageStore.commit(Session) line: 1112
Database.commit(Session) line: 1672
Session.commit(boolean) line: 448
Sequence.flush(Session) line: 135
Sequence.getNext(Session) line: 93
SequenceValue.getValue(Session) line: 30
Function.getValueWithArgs(Session, Expression[]) line: 1041
Function.getValue(Session) line: 417
Select.queryFlat(int, LocalResult, long) line: 494
Select.queryWithoutCache(int) line: 555
Select(Query).query(int) line: 233
CommandContainer.query(int) line: 80
CommandContainer(Command).executeQuery(int, boolean) line: 132
JdbcPreparedStatement.executeQuery() line: 96
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