Chris,
This change is not fully correct. The original record returned from
fetchNext() has a useCount on it, but fetchVersion does not transfer
that useCount to the prior version that it returns. So in a concurrent
environment, this code will leave some records with un-released useCounts.
=== modified file 'storage/falcon/Table.cpp'
--- a/storage/falcon/Table.cpp 2009-02-01 08:18:51 +0000
+++ b/storage/falcon/Table.cpp 2009-02-01 09:00:52 +0000
@@ -3581,14 +3581,22 @@ void Table::optimize(Connection *connect
for (Record *record; (record = fetchNext(recordNumber));)
{
recordNumber = record->recordNumber + 1;
record = record->fetchVersion(transaction);
if (record)
+ {
+ record->release(); // no need to keep it around
++count;
+ }
}
I think it should use a candidate like this.
- for (Record *record; (record = fetchNext(recordNumber));)
+ for (Record *candidate; (candidate = fetchNext(recordNumber));)
{
- recordNumber = record->recordNumber + 1;
+ recordNumber = candidate->recordNumber + 1;
- Record *record = candidate->fetchVersion(transaction);
+ record = record->fetchVersion(transaction);
if (record)
++count;
+ candidate->release(); // no need to keep it around
}
Christopher Powers wrote:
> #At file:///home/cpowers/work/dev/dev-04/mysql/
>
> 2992 Christopher Powers 2009-02-01
> Bug #42424, "Serious performance degradation after new scavenger"
>
> Increased scavenger wait increment from 10 to 20ms.
> Use progressive scavenger wait timeout for record allocation methods.
> modified:
> storage/falcon/Database.cpp
> storage/falcon/Database.h
> storage/falcon/Record.cpp
> storage/falcon/Table.cpp
>
> per-file messages:
> storage/falcon/Database.cpp
> Database::updateCardinalities()
> - Added log message
> storage/falcon/Database.h
> Increased SCAVENGE_WAIT_MS from 10ms to 20ms
> storage/falcon/Record.cpp
> Record::allocRecordData()
> - Progressively increase scavenger wait timeout
> storage/falcon/Table.cpp
> Table::allocRecordVersion() and ::allocRecord()
> - Progressively increase scavenger wait timeout
> === modified file 'storage/falcon/Database.cpp'
> --- a/storage/falcon/Database.cpp 2009-02-01 08:18:51 +0000
> +++ b/storage/falcon/Database.cpp 2009-02-01 09:00:52 +0000
> @@ -2474,6 +2474,7 @@ void Database::updateCardinalities(void)
> Sync syncTbl(&syncTables, "Database::updateCardinalities(2)");
> syncTbl.lock(Shared);
>
> + Log::log("Update cardinalities begin...\n");
> bool hit = false;
>
> try
> @@ -2522,6 +2523,8 @@ void Database::updateCardinalities(void)
> // Situations where this might happen can be due to problems with
> // writing to the serial log
> }
> +
> + Log::log("Update cardinalities complete.\n");
> }
>
> void Database::sync()
>
> === modified file 'storage/falcon/Database.h'
> --- a/storage/falcon/Database.h 2009-02-01 08:18:51 +0000
> +++ b/storage/falcon/Database.h 2009-02-01 09:00:52 +0000
> @@ -40,7 +40,7 @@
> #define VERSION_CURRENT COMBINED_VERSION(ODS_VERSION, ODS_MINOR_VERSION)
> #define VERSION_SERIAL_LOG COMBINED_VERSION(ODS_VERSION2, ODS_MINOR_VERSION1)
>
> -#define SCAVENGE_WAIT_MS 10 // Milliseconds per iteration to wait for the
> Scavenger
> +#define SCAVENGE_WAIT_MS 20 // Milliseconds per iteration to wait for the
> Scavenger
>
> static const int FALC0N_TRACE_TRANSACTIONS = 1;
> static const int FALC0N_SYNC_TEST = 2;
>
> === modified file 'storage/falcon/Record.cpp'
> --- a/storage/falcon/Record.cpp 2009-02-01 08:18:51 +0000
> +++ b/storage/falcon/Record.cpp 2009-02-01 09:00:52 +0000
> @@ -955,10 +955,11 @@ char* Record::allocRecordData(int length
>
> format->table->database->signalScavenger(true);
>
> - // Give the scavenger thread a chance to release some memory
> + // Give the scavenger thread a chance to release memory.
> + // Increase the wait time per iteration.
>
> Thread *thread = Thread::getThread("Database::ticker");
> - thread->sleep(10);
> + thread->sleep(n * SCAVENGE_WAIT_MS);
> }
>
> return NULL;
>
> === modified file 'storage/falcon/Table.cpp'
> --- a/storage/falcon/Table.cpp 2009-02-01 08:18:51 +0000
> +++ b/storage/falcon/Table.cpp 2009-02-01 09:00:52 +0000
> @@ -3581,14 +3581,22 @@ void Table::optimize(Connection *connect
> record = record->fetchVersion(transaction);
>
> if (record)
> + {
> + record->release(); // no need to keep it around
> ++count;
> + }
> }
>
> cardinality = count;
>
> + // Disable index optimization until a more
> + // efficient method is implemented using
> + // the IndexWalker (Bug#36442)
> +#if 0
> FOR_INDEXES(index, this);
> index->optimize(count, connection);
> END_FOR;
> +#endif
>
> database->commitSystemTransaction();
> }
> @@ -3681,10 +3689,11 @@ Record* Table::allocRecord(int recordNum
>
> database->signalScavenger(true);
>
> - // Give the scavenger thread a chance to release some memory
> + // Give the scavenger thread a chance to release memory.
> + // Increase the wait time per iteration.
>
> Thread *thread = Thread::getThread("Database::ticker");
> - thread->sleep(10);
> + thread->sleep(n * SCAVENGE_WAIT_MS);
> }
> }
>
>
>
