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Code cleanup for pg_buffercache, from Mark Kirkwood.

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This commit is contained in:
Tom Lane 2006-10-22 17:49:21 +00:00
parent c2c0b14086
commit bd95c74985
1 changed files with 34 additions and 66 deletions
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100
contrib/pg_buffercache/pg_buffercache_pages.c
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@ -3,12 +3,14 @@
* pg_buffercache_pages.c
* display some contents of the buffer cache
*
* $PostgreSQL: pgsql/contrib/pg_buffercache/pg_buffercache_pages.c,v 1.10 2006/10/19 18:32:46 tgl Exp $
* $PostgreSQL: pgsql/contrib/pg_buffercache/pg_buffercache_pages.c,v 1.11 2006/10/22 17:49:21 tgl Exp $
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "funcapi.h"
#include "access/heapam.h"
#include "catalog/pg_type.h"
#include "funcapi.h"
#include "storage/buf_internals.h"
#include "storage/bufmgr.h"
#include "utils/relcache.h"
@ -26,7 +28,6 @@ Datum pg_buffercache_pages(PG_FUNCTION_ARGS);
*/
typedef struct
{
uint32 bufferid;
Oid relfilenode;
Oid reltablespace;
@ -34,7 +35,6 @@ typedef struct
BlockNumber blocknum;
bool isvalid;
bool isdirty;
} BufferCachePagesRec;
@ -43,11 +43,8 @@ typedef struct
*/
typedef struct
{
AttInMetadata *attinmeta;
TupleDesc tupdesc;
BufferCachePagesRec *record;
char *values[NUM_BUFFERCACHE_PAGES_ELEM];
} BufferCachePagesContext;
@ -56,10 +53,10 @@ typedef struct
* relation node/tablespace/database/blocknum and dirty indicator.
*/
PG_FUNCTION_INFO_V1(pg_buffercache_pages);
Datum
pg_buffercache_pages(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
Datum result;
MemoryContext oldcontext;
@ -77,7 +74,10 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
/* 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 user function context for cross-call persistence */
fctx = (BufferCachePagesContext *) palloc(sizeof(BufferCachePagesContext));
/* Construct a tuple descriptor for the result rows. */
tupledesc = CreateTemplateTupleDesc(NUM_BUFFERCACHE_PAGES_ELEM, false);
TupleDescInitEntry(tupledesc, (AttrNumber) 1, "bufferid",
INT4OID, -1, 0);
@ -92,27 +92,14 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
TupleDescInitEntry(tupledesc, (AttrNumber) 6, "isdirty",
BOOLOID, -1, 0);
/* Generate attribute metadata needed later to produce tuples */
funcctx->attinmeta = TupleDescGetAttInMetadata(tupledesc);
/*
* Create a function context for cross-call persistence and initialize
* the buffer counters.
*/
fctx = (BufferCachePagesContext *) palloc(sizeof(BufferCachePagesContext));
funcctx->max_calls = NBuffers;
funcctx->user_fctx = fctx;
fctx->tupdesc = BlessTupleDesc(tupledesc);
/* Allocate NBuffers worth of BufferCachePagesRec records. */
fctx->record = (BufferCachePagesRec *) palloc(sizeof(BufferCachePagesRec) * NBuffers);
/* 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);
fctx->values[5] = (char *) palloc(2);
/* Set max calls and remember the user function context. */
funcctx->max_calls = NBuffers;
funcctx->user_fctx = fctx;
/* Return to original context when allocating transient memory */
MemoryContextSwitchTo(oldcontext);
@ -167,19 +154,11 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
if (funcctx->call_cntr < funcctx->max_calls)
{
uint32 i = funcctx->call_cntr;
char *values[NUM_BUFFERCACHE_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_BUFFERCACHE_PAGES_ELEM; j++)
{
values[j] = fctx->values[j];
}
Datum values[NUM_BUFFERCACHE_PAGES_ELEM];
bool nulls[NUM_BUFFERCACHE_PAGES_ELEM];
values[0] = Int32GetDatum(fctx->record[i].bufferid);
nulls[0] = false;
/*
* Set all fields except the bufferid to null if the buffer is unused
@ -188,43 +167,32 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
if (fctx->record[i].blocknum == InvalidBlockNumber ||
fctx->record[i].isvalid == false)
{
sprintf(values[0], "%u", fctx->record[i].bufferid);
values[1] = NULL;
values[2] = NULL;
values[3] = NULL;
values[4] = NULL;
values[5] = NULL;
nulls[1] = true;
nulls[2] = true;
nulls[3] = true;
nulls[4] = true;
nulls[5] = true;
}
else
{
sprintf(values[0], "%u", fctx->record[i].bufferid);
sprintf(values[1], "%u", fctx->record[i].relfilenode);
sprintf(values[2], "%u", fctx->record[i].reltablespace);
sprintf(values[3], "%u", fctx->record[i].reldatabase);
sprintf(values[4], "%u", fctx->record[i].blocknum);
if (fctx->record[i].isdirty)
{
strcpy(values[5], "t");
}
else
{
strcpy(values[5], "f");
}
values[1] = ObjectIdGetDatum(fctx->record[i].relfilenode);
nulls[1] = false;
values[2] = ObjectIdGetDatum(fctx->record[i].reltablespace);
nulls[2] = false;
values[3] = ObjectIdGetDatum(fctx->record[i].reldatabase);
nulls[3] = false;
values[4] = Int64GetDatum((int64) fctx->record[i].blocknum);
nulls[4] = false;
values[5] = BoolGetDatum(fctx->record[i].isdirty);
nulls[5] = 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);
}