#include "postgres.h"
#include "storage/buf_internals.h"

Include dependency graph for buf_table.c:

Data Structures
struct	BufferLookupEnt

Functions
Size	BufTableShmemSize (int size)

void	InitBufTable (int size)

uint32	BufTableHashCode (BufferTag *tagPtr)

int	BufTableLookup (BufferTag *tagPtr, uint32 hashcode)

int	BufTableInsert (BufferTag *tagPtr, uint32 hashcode, int buf_id)

void	BufTableDelete (BufferTag *tagPtr, uint32 hashcode)

Variables
static HTAB *	SharedBufHash

Function Documentation

◆ BufTableDelete()

void BufTableDelete	(	BufferTag *	tagPtr,
		uint32	hashcode
	)

Definition at line 148 of file buf_table.c.

 {
     BufferLookupEnt *result;
  
     result = (BufferLookupEnt *)
         hash_search_with_hash_value(SharedBufHash,
                                     tagPtr,
                                     hashcode,
                                     HASH_REMOVE,
                                     NULL);
  
     if (!result)                /* shouldn't happen */
         elog(ERROR, "shared buffer hash table corrupted");
 }

References elog, ERROR, HASH_REMOVE, hash_search_with_hash_value(), and SharedBufHash.

Referenced by InvalidateBuffer(), and InvalidateVictimBuffer().

◆ BufTableHashCode()

uint32 BufTableHashCode ( BufferTag * tagPtr )

Definition at line 78 of file buf_table.c.

 {
     return get_hash_value(SharedBufHash, (void *) tagPtr);
 }

References get_hash_value(), and SharedBufHash.

Referenced by BufferAlloc(), ExtendBufferedRelShared(), FindAndDropRelationBuffers(), InvalidateBuffer(), InvalidateVictimBuffer(), and PrefetchSharedBuffer().

◆ BufTableInsert()

int BufTableInsert	(	BufferTag *	tagPtr,
		uint32	hashcode,
		int	buf_id
	)

Definition at line 118 of file buf_table.c.

 {
     BufferLookupEnt *result;
     bool        found;
  
     Assert(buf_id >= 0);        /* -1 is reserved for not-in-table */
     Assert(tagPtr->blockNum != P_NEW);  /* invalid tag */
  
     result = (BufferLookupEnt *)
         hash_search_with_hash_value(SharedBufHash,
                                     tagPtr,
                                     hashcode,
                                     HASH_ENTER,
                                     &found);
  
     if (found)                  /* found something already in the table */
         return result->id;
  
     result->id = buf_id;
  
     return -1;
 }

References Assert, buftag::blockNum, HASH_ENTER, hash_search_with_hash_value(), BufferLookupEnt::id, P_NEW, and SharedBufHash.

Referenced by BufferAlloc(), and ExtendBufferedRelShared().

◆ BufTableLookup()

int BufTableLookup	(	BufferTag *	tagPtr,
		uint32	hashcode
	)

Definition at line 90 of file buf_table.c.

 {
     BufferLookupEnt *result;
  
     result = (BufferLookupEnt *)
         hash_search_with_hash_value(SharedBufHash,
                                     tagPtr,
                                     hashcode,
                                     HASH_FIND,
                                     NULL);
  
     if (!result)
         return -1;
  
     return result->id;
 }

References HASH_FIND, hash_search_with_hash_value(), BufferLookupEnt::id, and SharedBufHash.

Referenced by BufferAlloc(), FindAndDropRelationBuffers(), and PrefetchSharedBuffer().

◆ BufTableShmemSize()

Size BufTableShmemSize ( int size )

Definition at line 41 of file buf_table.c.

 {
     return hash_estimate_size(size, sizeof(BufferLookupEnt));
 }

References hash_estimate_size(), and size.

Referenced by StrategyShmemSize().

◆ InitBufTable()

void InitBufTable ( int size )

Definition at line 51 of file buf_table.c.

 {
     HASHCTL     info;
  
     /* assume no locking is needed yet */
  
     /* BufferTag maps to Buffer */
     info.keysize = sizeof(BufferTag);
     info.entrysize = sizeof(BufferLookupEnt);
     info.num_partitions = NUM_BUFFER_PARTITIONS;
  
     SharedBufHash = ShmemInitHash("Shared Buffer Lookup Table",
                                   size, size,
                                   &info,
                                   HASH_ELEM | HASH_BLOBS | HASH_PARTITION);
 }