@ -29,7 +29,7 @@
*
*
* IDENTIFICATION
* $ PostgreSQL : pgsql / src / backend / commands / vacuumlazy . c , v 1.130 2010 / 02 / 09 00 : 28 : 30 tgl Exp $
* $ PostgreSQL : pgsql / src / backend / commands / vacuumlazy . c , v 1.131 2010 / 02 / 09 21 : 43 : 30 tgl Exp $
*
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
*/
@ -50,7 +50,6 @@
# include "storage/bufmgr.h"
# include "storage/freespace.h"
# include "storage/lmgr.h"
# include "utils/inval.h"
# include "utils/lsyscache.h"
# include "utils/memutils.h"
# include "utils/pg_rusage.h"
@ -123,7 +122,7 @@ static void lazy_cleanup_index(Relation indrel,
LVRelStats * vacrelstats ) ;
static int lazy_vacuum_page ( Relation onerel , BlockNumber blkno , Buffer buffer ,
int tupindex , LVRelStats * vacrelstats ) ;
static bool lazy_truncate_heap ( Relation onerel , LVRelStats * vacrelstats ) ;
static void lazy_truncate_heap ( Relation onerel , LVRelStats * vacrelstats ) ;
static BlockNumber count_nondeletable_pages ( Relation onerel ,
LVRelStats * vacrelstats ) ;
static void lazy_space_alloc ( LVRelStats * vacrelstats , BlockNumber relblocks ) ;
@ -141,11 +140,8 @@ static int vac_cmp_itemptr(const void *left, const void *right);
*
* At entry , we have already established a transaction and opened
* and locked the relation .
*
* The return value indicates whether this function has held off
* interrupts - - if true , caller must RESUME_INTERRUPTS ( ) after commit .
*/
bool
void
lazy_vacuum_rel ( Relation onerel , VacuumStmt * vacstmt ,
BufferAccessStrategy bstrategy , bool * scanned_all )
{
@ -157,7 +153,6 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt,
TimestampTz starttime = 0 ;
bool scan_all ;
TransactionId freezeTableLimit ;
bool heldoff = false ;
pg_rusage_init ( & ru0 ) ;
@ -194,16 +189,9 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt,
/* Done with indexes */
vac_close_indexes ( nindexes , Irel , NoLock ) ;
/* Vacuum the Free Space Map */
FreeSpaceMapVacuum ( onerel ) ;
/*
* Optionally truncate the relation .
*
* NB : there should be as little code as possible after this point ,
* to minimize the chance of failure as well as the time spent ignoring
* cancel / die interrupts .
*
* Don ' t even think about it unless we have a shot at releasing a goodly
* number of pages . Otherwise , the time taken isn ' t worth it .
*/
@ -211,7 +199,10 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt,
if ( possibly_freeable > 0 & &
( possibly_freeable > = REL_TRUNCATE_MINIMUM | |
possibly_freeable > = vacrelstats - > rel_pages / REL_TRUNCATE_FRACTION ) )
heldoff = lazy_truncate_heap ( onerel , vacrelstats ) ;
lazy_truncate_heap ( onerel , vacrelstats ) ;
/* Vacuum the Free Space Map */
FreeSpaceMapVacuum ( onerel ) ;
/*
* Update statistics in pg_class . But only if we didn ' t skip any pages ;
@ -255,8 +246,6 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt,
if ( scanned_all )
* scanned_all = vacrelstats - > scanned_all ;
return heldoff ;
}
/*
@ -996,11 +985,8 @@ lazy_cleanup_index(Relation indrel,
/*
* lazy_truncate_heap - try to truncate off any empty pages at the end
*
* The return value indicates whether this function has held off
* interrupts - - if true , caller must RESUME_INTERRUPTS ( ) after commit .
*/
static bool
static void
lazy_truncate_heap ( Relation onerel , LVRelStats * vacrelstats )
{
BlockNumber old_rel_pages = vacrelstats - > rel_pages ;
@ -1016,7 +1002,7 @@ lazy_truncate_heap(Relation onerel, LVRelStats *vacrelstats)
* possible considering we already hold a lower - grade lock ) .
*/
if ( ! ConditionalLockRelation ( onerel , AccessExclusiveLock ) )
return false ;
return ;
/*
* Now that we have exclusive lock , look to see if the rel has grown
@ -1029,7 +1015,7 @@ lazy_truncate_heap(Relation onerel, LVRelStats *vacrelstats)
/* might as well use the latest news when we update pg_class stats */
vacrelstats - > rel_pages = new_rel_pages ;
UnlockRelation ( onerel , AccessExclusiveLock ) ;
return false ;
return ;
}
/*
@ -1044,34 +1030,22 @@ lazy_truncate_heap(Relation onerel, LVRelStats *vacrelstats)
{
/* can't do anything after all */
UnlockRelation ( onerel , AccessExclusiveLock ) ;
return false ;
return ;
}
/*
* Prevent cancel / die interrupts from now till commit . Once we have
* truncated , it is essential that we send the sinval message before
* releasing exclusive lock on the relation ; both of which will
* happen during commit . Other backends must receive the sinval
* message to reset their rd_targblock values before they can safely
* write to the table again . While we can ' t positively guarantee
* no error before commit , we can at least prevent cancel interrupts .
*
* XXX it would be better if we had a way to send the inval message
* nontransactionally ; an error after the truncate will mean that the
* message is lost . Note however that turning this all into a critical
* section would not be an improvement . Making it critical would mean
* that an error forces PANIC , whereas losing the sinval will at worst
* cause unexpected nonfatal errors in other sessions .
* Okay to truncate .
*/
HOLD_INTERRUPTS ( ) ;
/* force relcache inval so all backends reset their rd_targblock */
CacheInvalidateRelcache ( onerel ) ;
RelationTruncate ( onerel , new_rel_pages ) ;
/*
* Okay to truncate . Do as little as possible between here and commit .
* We can release the exclusive lock as soon as we have truncated . Other
* backends can ' t safely access the relation until they have processed the
* smgr invalidation that smgrtruncate sent out . . . but that should happen
* as part of standard invalidation processing once they acquire lock on
* the relation .
*/
RelationTruncate ( onerel , new_rel_pages ) ;
UnlockRelation ( onerel , AccessExclusiveLock ) ;
/* update statistics */
vacrelstats - > rel_pages = new_rel_pages ;
@ -1083,8 +1057,6 @@ lazy_truncate_heap(Relation onerel, LVRelStats *vacrelstats)
old_rel_pages , new_rel_pages ) ,
errdetail ( " %s. " ,
pg_rusage_show ( & ru0 ) ) ) ) ;
return true ; /* interrupts are held off */
}
/*
Tom Lane
16 years ago