Changeset: dea70dfccbcc for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=dea70dfccbcc
Modified Files:
monetdb5/modules/mal/oltp.c
monetdb5/modules/mal/oltp.mal
sql/scripts/96_oltp.sql
Branch: oltp
Log Message:
Use delay before releasing the lock
A hack to reduce the chance that transaction start in the final
phase of the commit protocol.
diffs (180 lines):
diff --git a/monetdb5/modules/mal/oltp.c b/monetdb5/modules/mal/oltp.c
--- a/monetdb5/modules/mal/oltp.c
+++ b/monetdb5/modules/mal/oltp.c
@@ -23,7 +23,8 @@
typedef struct{
Client cntxt; // user holding the write lock
lng start; // time when it started
- str query;
+ lng retention; // time when the lock is released
+ lng total; // accumulated lock time
int used; // how often it used, for balancing
int locked; // writelock set or not
} OLTPlockRecord;
@@ -60,8 +61,8 @@ OLTPreset(Client cntxt, MalBlkPtr mb, Ma
oltp_locks[i].locked = 0;
oltp_locks[i].cntxt = 0;
oltp_locks[i].start = 0;
- oltp_locks[i].query = 0;
oltp_locks[i].used = 0;
+ oltp_locks[i].retention = 0;
}
MT_lock_unset(&mal_oltpLock);
return MAL_SUCCEED;
@@ -110,40 +111,24 @@ str
OLTPlock(Client cntxt, MalBlkPtr mb, MalStkPtr stk, InstrPtr pci)
{
int i,lck;
- int clk;
+ int clk, wait= GDKms();
str sql,cpy;
(void) stk;
if ( oltp_delay == FALSE )
return MAL_SUCCEED;
- clk = GDKms();
#ifdef _DEBUG_OLTP_
- mnstr_printf(cntxt->fdout,"#OLTP %6d lock for client %d:", GDKms(),
cntxt->idx);
+ mnstr_printf(cntxt->fdout,"#OLTP %6d lock request for client %d:",
GDKms(), cntxt->idx);
printInstruction(cntxt->fdout,mb,stk,pci, LIST_MAL_ALL);
#endif
do{
- // checking the collision of read locks with write locks
- // does not require a lock on the table.
- // we can always try it again
- for( i=1; i< pci->argc; i++){
- lck= getVarConstant(mb, getArg(pci,i)).val.ival;
- if( (lck < 0 && oltp_locks[-lck].locked) || (lck > 0 &&
oltp_locks[lck].locked))
- break;
- }
- if ( i < pci->argc){
- MT_sleep_ms(LOCKDELAY);
- continue;
- }
-#ifdef _DEBUG_OLTP_
- mnstr_printf(cntxt->fdout,"#OLTP %6d lock does not cause
conflict\n", GDKms());
-#endif
-
MT_lock_set(&mal_oltpLock);
+ clk = GDKms();
// check if all write locks are available
for( i=1; i< pci->argc; i++){
lck= getVarConstant(mb, getArg(pci,i)).val.ival;
- if ( lck > 0 && oltp_locks[lck].locked )
+ if ( lck > 0 && (oltp_locks[lck].locked ||
oltp_locks[lck].retention > clk ))
break;
}
@@ -151,15 +136,14 @@ OLTPlock(Client cntxt, MalBlkPtr mb, Mal
#ifdef _DEBUG_OLTP_
mnstr_printf(cntxt->fdout,"#OLTP %6d set lock for
client %d\n", GDKms(), cntxt->idx);
#endif
- clk = GDKms();
for( i=1; i< pci->argc; i++){
lck= getVarConstant(mb, getArg(pci,i)).val.ival;
// only set the write locks
if( lck > 0){
oltp_locks[lck].cntxt = cntxt;
oltp_locks[lck].start = clk;
- oltp_locks[lck].used++;
oltp_locks[lck].locked = 1;
+ oltp_locks[lck].retention = 0;
}
}
MT_lock_unset(&mal_oltpLock);
@@ -171,7 +155,7 @@ OLTPlock(Client cntxt, MalBlkPtr mb, Mal
#endif
MT_sleep_ms(LOCKDELAY);
}
- } while( GDKms() - clk < LOCKTIMEOUT);
+ } while( lck - wait < LOCKTIMEOUT);
#ifdef _DEBUG_OLTP_
mnstr_printf(cntxt->fdout,"#OLTP %6d proceed query for client %d\n",
GDKms(), cntxt->idx);
@@ -194,6 +178,7 @@ str
OLTPrelease(Client cntxt, MalBlkPtr mb, MalStkPtr stk, InstrPtr pci)
{
int i,lck;
+ int delay, clk;
(void) cntxt;
(void) stk;
@@ -201,6 +186,7 @@ OLTPrelease(Client cntxt, MalBlkPtr mb,
return MAL_SUCCEED;
MT_lock_set(&mal_oltpLock);
+ clk = GDKms();
#ifdef _DEBUG_OLTP_
mnstr_printf(cntxt->fdout,"#OLTP %6d release the locks %d:", GDKms(),
cntxt->idx);
printInstruction(cntxt->fdout,mb,stk,pci, LIST_MAL_ALL);
@@ -208,10 +194,18 @@ OLTPrelease(Client cntxt, MalBlkPtr mb,
for( i=1; i< pci->argc; i++){
lck= getVarConstant(mb, getArg(pci,i)).val.ival;
if( lck > 0){
+ oltp_locks[lck].total += clk -
oltp_locks[lck].start;
+ oltp_locks[lck].used ++;
oltp_locks[lck].cntxt = 0;
oltp_locks[lck].start = 0;
- oltp_locks[lck].query = 0;
oltp_locks[lck].locked = 0;
+ delay = oltp_locks[lck].total/
oltp_locks[lck].used;
+ if( delay > LOCKDELAY || delay < LOCKDELAY/10)
+ delay = LOCKDELAY;
+ oltp_locks[lck].retention = clk + delay;
+#ifdef _DEBUG_OLTP_
+ mnstr_printf(cntxt->fdout,"#OLTP retention
period for lock %d: %d\n", lck,delay);
+#endif
}
}
MT_lock_unset(&mal_oltpLock);
@@ -226,7 +220,6 @@ OLTPtable(Client cntxt, MalBlkPtr mb, Ma
bat *userid = getArgReference_bat(stk,pci,1);
bat *lockid = getArgReference_bat(stk,pci,2);
bat *used = getArgReference_bat(stk,pci,3);
- bat *query = getArgReference_bat(stk,pci,4);
int i;
lng now;
str msg = MAL_SUCCEED;
@@ -266,16 +259,11 @@ OLTPtable(Client cntxt, MalBlkPtr mb, Ma
BUNappend(bu, str_nil, FALSE);
BUNappend(bl, &i, FALSE);
BUNappend(bc, &oltp_locks[i].used, FALSE);
- if( oltp_locks[i].query)
- BUNappend(bq, &oltp_locks[i].query, FALSE);
- else
- BUNappend(bq, str_nil, FALSE);
}
//OLTPdump_(cntxt,"#lock table\n");
BBPkeepref(*started = bs->batCacheid);
BBPkeepref(*userid = bu->batCacheid);
BBPkeepref(*lockid = bl->batCacheid);
BBPkeepref(*used = bc->batCacheid);
- BBPkeepref(*query = bq->batCacheid);
return msg;
}
diff --git a/monetdb5/modules/mal/oltp.mal b/monetdb5/modules/mal/oltp.mal
--- a/monetdb5/modules/mal/oltp.mal
+++ b/monetdb5/modules/mal/oltp.mal
@@ -24,7 +24,7 @@ pattern release(lck:int...):void
address OLTPrelease
comment "Release for all write locks needed";
-pattern table() (start:bat[:timestamp], usr:bat[:str], unit:bat[:int],
cnt:bat[:int], qry:bat[:str])
+pattern table() (start:bat[:timestamp], usr:bat[:str], unit:bat[:int],
cnt:bat[:int])
address OLTPtable
comment "Show status of lock table";
diff --git a/sql/scripts/96_oltp.sql b/sql/scripts/96_oltp.sql
--- a/sql/scripts/96_oltp.sql
+++ b/sql/scripts/96_oltp.sql
@@ -19,8 +19,7 @@ returns table(
started timestamp,
username string,
lockid integer,
- cnt integer,
- query string
+ cnt integer
)
external name oltp."table";
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