memtable.h File Reference

In-memory table of the records that have been modified most recently. More...

#include <stdint.h>
#include <stdlib.h>

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Data Structures
struct	MemTableRecord
	Single Record in the MemTable. More...
struct	MemTable
	MemTable of the Database. More...

Macros
#define	MEMTABLE_SIZE   1024
	Max number of MemTableRecords in a MemTable.

Functions
struct MemTable *	MemTable_new ()
	Creates a new empty MemTable.
struct MemTableRecord *	MemTable_get (const struct MemTable *memtable, const char *key, size_t key_len)
	Gets a MemTableRecord from a MemTable by key.
void	MemTable_set (struct MemTable *memtable, const char *key, size_t key_len, int64_t value_loc)
	Sets a key-value pair in a MemTable.
void	MemTable_delete (struct MemTable *memtable, const char *key, size_t key_len)
	Deletes a record from a MemTable.
void	MemTable_free (struct MemTable *memtable)
	Frees a MemTable and its records.

Detailed Description

In-memory table of the records that have been modified most recently.

Author

Adam Comer adamb.nosp@m.come.nosp@m.r@gma.nosp@m.il.c.nosp@m.om

Date

May 15, 2020

Copyright

Apache-2.0 License

Function Documentation

MemTable_delete()

void MemTable_delete	(	struct MemTable *	memtable,
		const char *	key,
		size_t	key_len )

Deletes a record from a MemTable.

This function uses binary search for a runtime of O(log(n)).

Note: This function will set a tombstone to propagate the delete into the SSTables.

Parameters

memtable	The MemTable to delete a record from.
key	The key to delete.
key_len	The length of the key.

MemTable_free()

void MemTable_free

(

struct MemTable *

memtable

)

Frees a MemTable and its records.

Note: This function will free all the MemTableRecords plus their keys in this MemTable.

Parameters

memtable

The MemTable to free.

MemTable_get()

struct MemTableRecord * MemTable_get	(	const struct MemTable *	memtable,
		const char *	key,
		size_t	key_len )

Gets a MemTableRecord from a MemTable by key.

This function will return NULL if none of the records in the MemTable.

This function uses binary search for a runtime of O(log(n)).

Parameters

memtable	The MemTable to search.
key	The key to search the MemTable with.
key_len	The length of the key.

Returns

A MemTableRecord if the record exists or NULL if it doesn't not exist.

MemTable_new()

struct MemTable * MemTable_new

(

)

Creates a new empty MemTable.

Note: Free this MemTable with MemTable_free.

Returns

A new empty MemTable.

MemTable_set()

void MemTable_set	(	struct MemTable *	memtable,
		const char *	key,
		size_t	key_len,
		int64_t	value_loc )

Sets a key-value pair in a MemTable.

This function uses binary search for a runtime of O(log(n)).

Parameters

memtable	The MemTable to set a value to.
key	The key to set this value for.
key_len	The length of the key.
value_loc	The seek location to the value in the ValueLog.