#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, 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().

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 | HASH_FIXED_SIZE);
}