Column | references | Description
----------------+----------------------+------------------------------------
reltablespace | pg_tablespace.oid | Tablespace oid of the relation.
- reldatabase | pg_database.oid | Database for the relation.
- relfilenode | pg_class.relfilenode | Refilenode of the relation.
+ reldatabase | pg_database.oid | Database oid of the relation.
+ relfilenode | pg_class.relfilenode | Relfilenode of the relation.
avgrequest | | Moving average of free space
- | | requests.
- lastpagecount | | Count of pages examined for useful
- | | free space.
- nextpage | | page index (from 0) to start next
+ | | requests (NULL for indexes)
+ lastpagecount | | Count of pages last reported as
+ | | containing useful free space.
+ storedpages | | Count of pages actually stored
+ | | in free space map.
+ nextpage | | Page index (from 0) to start next
| | search at.
Column | references | Description
----------------+----------------------+------------------------------------
reltablespace | pg_tablespace.oid | Tablespace oid of the relation.
- reldatabase | pg_database.oid | Database for the relation.
- relfilenode | pg_class.relfilenode | Refilenode of the relation.
- relblocknumber | | Page offset in the relation.
+ reldatabase | pg_database.oid | Database oid of the relation.
+ relfilenode | pg_class.relfilenode | Relfilenode of the relation.
+ relblocknumber | | Page number in the relation.
bytes | | Free bytes in the page, or NULL
| | for an index page (see below).
For pg_freespacemap_relations, there is one row for each relation in the free
- space map.
+ space map. storedpages is the number of pages actually stored in the map,
+ while lastpagecount is the number of pages VACUUM last tried to store
+ (ie, the number that VACUUM thought had useful amounts of free space).
+
+ If storedpages is consistently less than lastpagecount then it'd be a good
+ idea to increase max_fsm_pages. Also, if the number of rows in
+ pg_freespacemap_relations is close to max_fsm_relations, then you should
+ consider increasing max_fsm_relations.
For pg_freespacemap_pages, there is one row for each page in the free space
- map.
+ map. The number of rows for a relation will match the storedpages column
+ in pg_freespacemap_relations.
- Because the map is shared by all the databases, there are relations and pages
- from relations not belonging to the current database.
+ For indexes, what is tracked is entirely-unused pages, rather than free
+ space within pages. Therefore, the average request size and free bytes
+ within a page are not meaningful, and are shown as NULL.
- The view 'freespacemap_pages' can contain pages for btree indexes if they
- were emptied by a vacuum process. The bytes field is set to NULL in this case.
+ Because the map is shared by all the databases, it will include relations
+ not belonging to the current database.
When either of the views are accessed, internal free space map locks are
taken, and a copy of the map data is made for them to display.
regression=# \d pg_freespacemap_relations
View "public.pg_freespacemap_relations"
- Column | Type | Modifiers
+ Column | Type | Modifiers
---------------+---------+-----------
- reltablespace | oid |
- reldatabase | oid |
- relfilenode | oid |
- avgrequest | bigint |
- lastpagecount | integer |
- nextpage | integer |
+ reltablespace | oid |
+ reldatabase | oid |
+ relfilenode | oid |
+ avgrequest | integer |
+ lastpagecount | integer |
+ storedpages | integer |
+ nextpage | integer |
View definition:
- SELECT p.reltablespace, p.reldatabase, p.relfilenode, p.avgrequest, p.lastpagecount, p.nextpage
- FROM pg_freespacemap_relations() p(reltablespace oid, reldatabase oid, relfilenode oid, avgrequest bigint, lastpagecount integer, nextpage integer);
+ SELECT p.reltablespace, p.reldatabase, p.relfilenode, p.avgrequest, p.lastpagecount, p.storedpages, p.nextpage
+ FROM pg_freespacemap_relations() p(reltablespace oid, reldatabase oid, relfilenode oid, avgrequest integer, lastpagecount integer, storedpages integer, nextpage integer);
-regression=# SELECT c.relname, r.avgrequest, r.lastpagecount, r.nextpage
+regression=# SELECT c.relname, r.avgrequest, r.lastpagecount, r.storedpages
FROM pg_freespacemap_relations r INNER JOIN pg_class c
ON c.relfilenode = r.relfilenode INNER JOIN pg_database d
ON r.reldatabase = d.oid AND (d.datname = current_database())
- ORDER BY c.relname LIMIT 10;
- relname | avgrequest | lastpagecount | nextpage
---------------+------------+---------------+----------
- a_star | 250 | 1 | 0
- abstime_tbl | 249 | 1 | 0
- aggtest | 250 | 1 | 0
- altinhoid | 250 | 1 | 0
- altstartwith | 250 | 1 | 0
- arrtest | 254 | 1 | 0
- b_star | 250 | 1 | 0
- box_tbl | 250 | 1 | 0
- bt_f8_heap | 92 | 1 | 0
- bt_i4_heap | 94 | 1 | 0
+ ORDER BY r.storedpages DESC LIMIT 10;
+ relname | avgrequest | lastpagecount | storedpages
+---------------------------------+------------+---------------+-------------
+ onek | 256 | 109 | 109
+ pg_attribute | 167 | 93 | 93
+ pg_class | 191 | 49 | 49
+ pg_attribute_relid_attnam_index | | 48 | 48
+ onek2 | 256 | 37 | 37
+ pg_depend | 95 | 26 | 26
+ pg_type | 199 | 16 | 16
+ pg_rewrite | 1011 | 13 | 13
+ pg_class_relname_nsp_index | | 10 | 10
+ pg_proc | 302 | 8 | 8
(10 rows)
-regression=#
-
Sample output - pg_freespacemap_pages
-------------
-regression=# \d pg_freespacemap_pages;
+regression=# \d pg_freespacemap_pages
View "public.pg_freespacemap_pages"
Column | Type | Modifiers
----------------+---------+-----------
bt_i4_heap | 49 | 8008
(10 rows)
-regression=#
-
Author
* pg_freespacemap.c
* display some contents of the free space relation and page maps.
*
- * $PostgreSQL: pgsql/contrib/pg_freespacemap/pg_freespacemap.c,v 1.4 2006/04/26 22:46:09 momjian Exp $
+ * $PostgreSQL: pgsql/contrib/pg_freespacemap/pg_freespacemap.c,v 1.5 2006/05/04 20:39:34 tgl Exp $
*-------------------------------------------------------------------------
*/
#include "postgres.h"
+
#include "funcapi.h"
+#include "access/heapam.h"
#include "catalog/pg_type.h"
#include "storage/freespace.h"
-#include "utils/relcache.h"
+
#define NUM_FREESPACE_PAGES_ELEM 5
-#define NUM_FREESPACE_RELATIONS_ELEM 6
+#define NUM_FREESPACE_RELATIONS_ELEM 7
#if defined(WIN32) || defined(__CYGWIN__)
/* Need DLLIMPORT for some things that are not so marked in main headers */
/*
- * Record structure holding the to be exposed free space page data.
+ * Record structure holding the to be exposed per-page data.
*/
typedef struct
{
-
- uint32 reltablespace;
- uint32 reldatabase;
- uint32 relfilenode;
- uint32 relblocknumber;
- uint32 bytes;
- bool isindex;
-
+ Oid reltablespace;
+ Oid reldatabase;
+ Oid relfilenode;
+ BlockNumber relblocknumber;
+ Size bytes;
+ bool isindex;
} FreeSpacePagesRec;
/*
- * Record structure holding the to be exposed free space relation data.
+ * Record structure holding the to be exposed per-relation data.
*/
typedef struct
{
-
- uint32 reltablespace;
- uint32 reldatabase;
- uint32 relfilenode;
- int64 avgrequest;
- int lastpagecount;
- int nextpage;
-
+ Oid reltablespace;
+ Oid reldatabase;
+ Oid relfilenode;
+ Size avgrequest;
+ int lastpagecount;
+ int storedpages;
+ int nextpage;
+ bool isindex;
} FreeSpaceRelationsRec;
*/
typedef struct
{
-
- AttInMetadata *attinmeta;
+ TupleDesc tupdesc;
FreeSpacePagesRec *record;
- char *values[NUM_FREESPACE_PAGES_ELEM];
-
} FreeSpacePagesContext;
*/
typedef struct
{
-
- AttInMetadata *attinmeta;
+ TupleDesc tupdesc;
FreeSpaceRelationsRec *record;
- char *values[NUM_FREESPACE_RELATIONS_ELEM];
-
} FreeSpaceRelationsContext;
* Function returning page data from the Free Space Map (FSM).
*/
PG_FUNCTION_INFO_V1(pg_freespacemap_pages);
+
Datum
pg_freespacemap_pages(PG_FUNCTION_ARGS)
{
-
FuncCallContext *funcctx;
Datum result;
MemoryContext oldcontext;
FreeSpacePagesContext *fctx; /* User function context. */
TupleDesc tupledesc;
HeapTuple tuple;
-
FSMHeader *FreeSpaceMap; /* FSM main structure. */
FSMRelation *fsmrel; /* Individual relation. */
-
if (SRF_IS_FIRSTCALL())
{
- uint32 i;
- uint32 numPages; /* Max possible no. of pages in map. */
- int nPages; /* Mapped pages for a relation. */
+ int i;
+ int numPages; /* Max possible no. of pages in map. */
+ int nPages; /* Mapped pages for a relation. */
/*
* Get the free space map data structure.
/* Switch context when allocating stuff to be used in later calls */
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
- /* Construct a tuple to return. */
+ /*
+ * Create a function context for cross-call persistence.
+ */
+ fctx = (FreeSpacePagesContext *) palloc(sizeof(FreeSpacePagesContext));
+ funcctx->user_fctx = fctx;
+
+ /* Construct a tuple descriptor for the result rows. */
tupledesc = CreateTemplateTupleDesc(NUM_FREESPACE_PAGES_ELEM, false);
TupleDescInitEntry(tupledesc, (AttrNumber) 1, "reltablespace",
OIDOID, -1, 0);
TupleDescInitEntry(tupledesc, (AttrNumber) 5, "bytes",
INT4OID, -1, 0);
- /* Generate attribute metadata needed later to produce tuples */
- funcctx->attinmeta = TupleDescGetAttInMetadata(tupledesc);
+ fctx->tupdesc = BlessTupleDesc(tupledesc);
/*
- * Create a function context for cross-call persistence and initialize
- * the counters.
- */
- fctx = (FreeSpacePagesContext *) palloc(sizeof(FreeSpacePagesContext));
- funcctx->user_fctx = fctx;
-
- /* Set an upper bound on the calls */
- funcctx->max_calls = numPages;
-
-
- /* Allocate numPages worth of FreeSpacePagesRec records, this is also
+ * Allocate numPages worth of FreeSpacePagesRec records, this is
* an upper bound.
*/
fctx->record = (FreeSpacePagesRec *) palloc(sizeof(FreeSpacePagesRec) * numPages);
- /* allocate the strings for tuple formation */
- fctx->values[0] = (char *) palloc(3 * sizeof(uint32) + 1);
- fctx->values[1] = (char *) palloc(3 * sizeof(uint32) + 1);
- fctx->values[2] = (char *) palloc(3 * sizeof(uint32) + 1);
- fctx->values[3] = (char *) palloc(3 * sizeof(uint32) + 1);
- fctx->values[4] = (char *) palloc(3 * sizeof(uint32) + 1);
-
-
/* Return to original context when allocating transient memory */
MemoryContextSwitchTo(oldcontext);
-
/*
- * Lock free space map and scan though all the relations,
- * for each relation, gets all its mapped pages.
+ * Lock free space map and scan though all the relations.
+ * For each relation, gets all its mapped pages.
*/
LWLockAcquire(FreeSpaceLock, LW_EXCLUSIVE);
-
i = 0;
for (fsmrel = FreeSpaceMap->usageList; fsmrel; fsmrel = fsmrel->nextUsage)
{
-
if (fsmrel->isIndex)
- { /* Index relation. */
+ {
+ /* Index relation. */
IndexFSMPageData *page;
page = (IndexFSMPageData *)
- (FreeSpaceMap->arena + fsmrel->firstChunk * CHUNKBYTES);
+ (FreeSpaceMap->arena + fsmrel->firstChunk * CHUNKBYTES);
for (nPages = 0; nPages < fsmrel->storedPages; nPages++)
{
-
fctx->record[i].reltablespace = fsmrel->key.spcNode;
fctx->record[i].reldatabase = fsmrel->key.dbNode;
fctx->record[i].relfilenode = fsmrel->key.relNode;
}
}
else
- { /* Heap relation. */
+ {
+ /* Heap relation. */
FSMPageData *page;
page = (FSMPageData *)
- (FreeSpaceMap->arena + fsmrel->firstChunk * CHUNKBYTES);
+ (FreeSpaceMap->arena + fsmrel->firstChunk * CHUNKBYTES);
for (nPages = 0; nPages < fsmrel->storedPages; nPages++)
{
page++;
i++;
}
-
}
-
}
- /* Set the real no. of calls as we know it now! */
- funcctx->max_calls = i;
-
/* Release free space map. */
LWLockRelease(FreeSpaceLock);
+
+ /* Set the real no. of calls as we know it now! */
+ Assert(i <= numPages);
+ funcctx->max_calls = i;
}
funcctx = SRF_PERCALL_SETUP();
/* Get the saved state */
fctx = funcctx->user_fctx;
-
if (funcctx->call_cntr < funcctx->max_calls)
{
- uint32 i = funcctx->call_cntr;
- char *values[NUM_FREESPACE_PAGES_ELEM];
- int j;
-
- /*
- * Use a temporary values array, initially pointing to fctx->values,
- * so it can be reassigned w/o losing the storage for subsequent
- * calls.
- */
- for (j = 0; j < NUM_FREESPACE_PAGES_ELEM; j++)
- {
- values[j] = fctx->values[j];
- }
-
-
- sprintf(values[0], "%u", fctx->record[i].reltablespace);
- sprintf(values[1], "%u", fctx->record[i].reldatabase);
- sprintf(values[2], "%u", fctx->record[i].relfilenode);
- sprintf(values[3], "%u", fctx->record[i].relblocknumber);
-
+ int i = funcctx->call_cntr;
+ FreeSpacePagesRec *record = &fctx->record[i];
+ Datum values[NUM_FREESPACE_PAGES_ELEM];
+ bool nulls[NUM_FREESPACE_PAGES_ELEM];
+
+ values[0] = ObjectIdGetDatum(record->reltablespace);
+ nulls[0] = false;
+ values[1] = ObjectIdGetDatum(record->reldatabase);
+ nulls[1] = false;
+ values[2] = ObjectIdGetDatum(record->relfilenode);
+ nulls[2] = false;
+ values[3] = Int64GetDatum((int64) record->relblocknumber);
+ nulls[3] = false;
/*
* Set (free) bytes to NULL for an index relation.
*/
- if (fctx->record[i].isindex == true)
+ if (record->isindex)
{
- values[4] = NULL;
+ nulls[4] = true;
}
else
{
- sprintf(values[4], "%u", fctx->record[i].bytes);
+ values[4] = UInt32GetDatum(record->bytes);
+ nulls[4] = false;
}
-
/* Build and return the tuple. */
- tuple = BuildTupleFromCStrings(funcctx->attinmeta, values);
+ tuple = heap_form_tuple(fctx->tupdesc, values, nulls);
result = HeapTupleGetDatum(tuple);
-
SRF_RETURN_NEXT(funcctx, result);
}
else
SRF_RETURN_DONE(funcctx);
-
}
* Function returning relation data from the Free Space Map (FSM).
*/
PG_FUNCTION_INFO_V1(pg_freespacemap_relations);
+
Datum
pg_freespacemap_relations(PG_FUNCTION_ARGS)
{
-
FuncCallContext *funcctx;
Datum result;
MemoryContext oldcontext;
- FreeSpaceRelationsContext *fctx; /* User function context. */
+ FreeSpaceRelationsContext *fctx; /* User function context. */
TupleDesc tupledesc;
HeapTuple tuple;
-
FSMHeader *FreeSpaceMap; /* FSM main structure. */
FSMRelation *fsmrel; /* Individual relation. */
-
if (SRF_IS_FIRSTCALL())
{
- uint32 i;
- uint32 numRelations; /* Max no. of Relations in map. */
+ int i;
+ int numRelations; /* Max no. of Relations in map. */
/*
* Get the free space map data structure.
/* Switch context when allocating stuff to be used in later calls */
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
- /* Construct a tuple to return. */
+ /*
+ * Create a function context for cross-call persistence.
+ */
+ fctx = (FreeSpaceRelationsContext *) palloc(sizeof(FreeSpaceRelationsContext));
+ funcctx->user_fctx = fctx;
+
+ /* Construct a tuple descriptor for the result rows. */
tupledesc = CreateTemplateTupleDesc(NUM_FREESPACE_RELATIONS_ELEM, false);
TupleDescInitEntry(tupledesc, (AttrNumber) 1, "reltablespace",
OIDOID, -1, 0);
TupleDescInitEntry(tupledesc, (AttrNumber) 3, "relfilenode",
OIDOID, -1, 0);
TupleDescInitEntry(tupledesc, (AttrNumber) 4, "avgrequest",
- INT8OID, -1, 0);
- TupleDescInitEntry(tupledesc, (AttrNumber) 5, "lastpageCount",
INT4OID, -1, 0);
- TupleDescInitEntry(tupledesc, (AttrNumber) 6, "nextpage",
+ TupleDescInitEntry(tupledesc, (AttrNumber) 5, "lastpagecount",
+ INT4OID, -1, 0);
+ TupleDescInitEntry(tupledesc, (AttrNumber) 6, "storedpages",
+ INT4OID, -1, 0);
+ TupleDescInitEntry(tupledesc, (AttrNumber) 7, "nextpage",
INT4OID, -1, 0);
- /* Generate attribute metadata needed later to produce tuples */
- funcctx->attinmeta = TupleDescGetAttInMetadata(tupledesc);
+ fctx->tupdesc = BlessTupleDesc(tupledesc);
/*
- * Create a function context for cross-call persistence and initialize
- * the counters.
- */
- fctx = (FreeSpaceRelationsContext *) palloc(sizeof(FreeSpaceRelationsContext));
- funcctx->user_fctx = fctx;
-
- /* Set an upper bound on the calls */
- funcctx->max_calls = numRelations;
-
-
- /* Allocate numRelations worth of FreeSpaceRelationsRec records,
+ * Allocate numRelations worth of FreeSpaceRelationsRec records,
* this is also an upper bound.
*/
fctx->record = (FreeSpaceRelationsRec *) palloc(sizeof(FreeSpaceRelationsRec) * numRelations);
- /* allocate the strings for tuple formation */
- fctx->values[0] = (char *) palloc(3 * sizeof(uint32) + 1);
- fctx->values[1] = (char *) palloc(3 * sizeof(uint32) + 1);
- fctx->values[2] = (char *) palloc(3 * sizeof(uint32) + 1);
- fctx->values[3] = (char *) palloc(3 * sizeof(int64) + 1);
- fctx->values[4] = (char *) palloc(3 * sizeof(int32) + 1);
- fctx->values[5] = (char *) palloc(3 * sizeof(int32) + 1);
-
-
/* Return to original context when allocating transient memory */
MemoryContextSwitchTo(oldcontext);
-
/*
- * Lock free space map and scan though all the relations,
+ * Lock free space map and scan though all the relations.
*/
LWLockAcquire(FreeSpaceLock, LW_EXCLUSIVE);
-
i = 0;
for (fsmrel = FreeSpaceMap->usageList; fsmrel; fsmrel = fsmrel->nextUsage)
{
-
fctx->record[i].reltablespace = fsmrel->key.spcNode;
fctx->record[i].reldatabase = fsmrel->key.dbNode;
fctx->record[i].relfilenode = fsmrel->key.relNode;
fctx->record[i].avgrequest = (int64)fsmrel->avgRequest;
fctx->record[i].lastpagecount = fsmrel->lastPageCount;
+ fctx->record[i].storedpages = fsmrel->storedPages;
fctx->record[i].nextpage = fsmrel->nextPage;
+ fctx->record[i].isindex = fsmrel->isIndex;
i++;
-
-
}
- /* Set the real no. of calls as we know it now! */
- funcctx->max_calls = i;
-
/* Release free space map. */
LWLockRelease(FreeSpaceLock);
+
+ /* Set the real no. of calls as we know it now! */
+ Assert(i <= numRelations);
+ funcctx->max_calls = i;
}
funcctx = SRF_PERCALL_SETUP();
/* Get the saved state */
fctx = funcctx->user_fctx;
-
if (funcctx->call_cntr < funcctx->max_calls)
{
- uint32 i = funcctx->call_cntr;
- char *values[NUM_FREESPACE_RELATIONS_ELEM];
- int j;
-
+ int i = funcctx->call_cntr;
+ FreeSpaceRelationsRec *record = &fctx->record[i];
+ Datum values[NUM_FREESPACE_RELATIONS_ELEM];
+ bool nulls[NUM_FREESPACE_RELATIONS_ELEM];
+
+ values[0] = ObjectIdGetDatum(record->reltablespace);
+ nulls[0] = false;
+ values[1] = ObjectIdGetDatum(record->reldatabase);
+ nulls[1] = false;
+ values[2] = ObjectIdGetDatum(record->relfilenode);
+ nulls[2] = false;
/*
- * Use a temporary values array, initially pointing to fctx->values,
- * so it can be reassigned w/o losing the storage for subsequent
- * calls.
+ * avgrequest isn't meaningful for an index
*/
- for (j = 0; j < NUM_FREESPACE_RELATIONS_ELEM; j++)
+ if (record->isindex)
{
- values[j] = fctx->values[j];
+ nulls[3] = true;
}
-
-
- sprintf(values[0], "%u", fctx->record[i].reltablespace);
- sprintf(values[1], "%u", fctx->record[i].reldatabase);
- sprintf(values[2], "%u", fctx->record[i].relfilenode);
- sprintf(values[3], INT64_FORMAT, fctx->record[i].avgrequest);
- sprintf(values[4], "%d", fctx->record[i].lastpagecount);
- sprintf(values[5], "%d", fctx->record[i].nextpage);
-
-
+ else
+ {
+ values[3] = UInt32GetDatum(record->avgrequest);
+ nulls[3] = false;
+ }
+ values[4] = Int32GetDatum(record->lastpagecount);
+ nulls[4] = false;
+ values[5] = Int32GetDatum(record->storedpages);
+ nulls[5] = false;
+ values[6] = Int32GetDatum(record->nextpage);
+ nulls[6] = false;
/* Build and return the tuple. */
- tuple = BuildTupleFromCStrings(funcctx->attinmeta, values);
+ tuple = heap_form_tuple(fctx->tupdesc, values, nulls);
result = HeapTupleGetDatum(tuple);
-
SRF_RETURN_NEXT(funcctx, result);
}
else
SRF_RETURN_DONE(funcctx);
-
-
}
projects / postgresql.git / commitdiff