This is probably terrible timing, but I noticed Tom had done some nice tidying up on pg_freespacemap to eliminate the clumsy conversion to and from strings. This patch does a similar thing for pg_buffercache.
I did wonder about not showing buffers that are invalid or not in use (currently displays all attributes bar the id as NULL). Comments? Cheers Mark
Index: contrib/pg_buffercache/pg_buffercache_pages.c =================================================================== RCS file: /projects/cvsroot/pgsql/contrib/pg_buffercache/pg_buffercache_pages.c,v retrieving revision 1.10 diff -c -r1.10 pg_buffercache_pages.c *** contrib/pg_buffercache/pg_buffercache_pages.c 19 Oct 2006 18:32:46 -0000 1.10 --- contrib/pg_buffercache/pg_buffercache_pages.c 22 Oct 2006 06:27:52 -0000 *************** *** 8,13 **** --- 8,14 ---- */ #include "postgres.h" #include "funcapi.h" + #include "access/heapam.h" #include "catalog/pg_type.h" #include "storage/buf_internals.h" #include "storage/bufmgr.h" *************** *** 44,52 **** typedef struct { ! AttInMetadata *attinmeta; BufferCachePagesRec *record; - char *values[NUM_BUFFERCACHE_PAGES_ELEM]; } BufferCachePagesContext; --- 45,52 ---- typedef struct { ! TupleDesc tupdesc; BufferCachePagesRec *record; } BufferCachePagesContext; *************** *** 77,83 **** /* Switch context when allocating stuff to be used in later calls */ oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx); ! /* Construct a tuple to return. */ tupledesc = CreateTemplateTupleDesc(NUM_BUFFERCACHE_PAGES_ELEM, false); TupleDescInitEntry(tupledesc, (AttrNumber) 1, "bufferid", INT4OID, -1, 0); --- 77,87 ---- /* Switch context when allocating stuff to be used in later calls */ oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx); ! ! /* Create a user function context for cross-call persistence */ ! fctx = (BufferCachePagesContext *) palloc(sizeof(BufferCachePagesContext)); ! ! /* Construct a tuple to return, and save its descriptor. */ tupledesc = CreateTemplateTupleDesc(NUM_BUFFERCACHE_PAGES_ELEM, false); TupleDescInitEntry(tupledesc, (AttrNumber) 1, "bufferid", INT4OID, -1, 0); *************** *** 92,118 **** 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; /* 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); /* Return to original context when allocating transient memory */ MemoryContextSwitchTo(oldcontext); --- 96,109 ---- TupleDescInitEntry(tupledesc, (AttrNumber) 6, "isdirty", BOOLOID, -1, 0); ! fctx->tupdesc = BlessTupleDesc(tupledesc); /* Allocate NBuffers worth of BufferCachePagesRec records. */ fctx->record = (BufferCachePagesRec *) palloc(sizeof(BufferCachePagesRec) * NBuffers); ! /* 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); *************** *** 167,184 **** 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]; ! } /* --- 158,165 ---- if (funcctx->call_cntr < funcctx->max_calls) { uint32 i = funcctx->call_cntr; ! Datum values[NUM_BUFFERCACHE_PAGES_ELEM]; ! bool nulls[NUM_BUFFERCACHE_PAGES_ELEM]; /* *************** *** 189,224 **** 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; } 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"); } } /* Build and return the tuple. */ ! tuple = BuildTupleFromCStrings(funcctx->attinmeta, values); result = HeapTupleGetDatum(tuple); --- 170,212 ---- fctx->record[i].isvalid == false) { ! values[0] = Int32GetDatum(fctx->record[i].bufferid); ! nulls[0] = false; ! nulls[1] = true; ! nulls[2] = true; ! nulls[3] = true; ! nulls[4] = true; ! nulls[5] = true; } else { ! values[0] = Int32GetDatum(fctx->record[i].bufferid); ! nulls[0] = false; ! 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; if (fctx->record[i].isdirty) { ! values[5] = BoolGetDatum(true); } else { ! values[5] = BoolGetDatum(false); } + nulls[5] = false; } /* Build and return the tuple. */ ! tuple = heap_form_tuple(fctx->tupdesc, values, nulls); result = HeapTupleGetDatum(tuple);
---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings