Code cleanup for pg_buffercache, from Mark Kirkwood.

diff --git a/contrib/pg_buffercache/pg_buffercache_pages.c b/contrib/pg_buffercache/pg_buffercache_pages.c
index a75e8a2..ed7b6f6 100644 (file)
--- a/contrib/pg_buffercache/pg_buffercache_pages.c
+++ b/contrib/pg_buffercache/pg_buffercache_pages.c
@@ -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);
-
 }