short_txkey

Documentation

Overview

Package txkey consolidates in one place the use of keys to index into our various storage/txn back-ends. The short_txkey version omits the index and shard, since these are implicitly part of our database-per-shard in an index scheme. In other words, every database is only in exactly one shard of one index already. There is no need to repeat the index and shard in these keys.

Index

• func AllShardPrefix(index, field, view string) (r []byte)
• func FieldPrefix(index, field string) (r []byte)
• func IndexOnlyPrefix(indexName string) (r []byte)
• func Key(index, field, view string, shard, roaringContainerKey uint64) (r []byte)
• func KeyAndPrefix(index, field, view string, shard, roaringContainerKey uint64) (key, prefix []byte)
• func KeyExtractContainerKey(bkey []byte) (containerKey uint64)
• func MustValidateKey(bkey []byte)
• func Prefix(index, field, view string, shard uint64) (r []byte)
• func PrefixFromKey(bkey []byte) (prefix []byte)
• func PrefixToString(pre []byte) (r string)
• func Split(bkey []byte) (field, view string, ckey uint64)
• func SplitPrefix(pre []byte) (field, view string)
• func ToString(bkey []byte) (r string)
• type FieldView
  • func FieldViewFromFullKey(fullKey []byte) FieldView
  • func FieldViewFromPrefix(prefix []byte) FieldView

Functions

func AllShardPrefix

func AllShardPrefix(index, field, view string) (r []byte)

func FieldPrefix

func FieldPrefix(index, field string) (r []byte)

same for deleting a whole field.

func IndexOnlyPrefix

func IndexOnlyPrefix(indexName string) (r []byte)

IndexOnlyPrefix returns a "~" prefix suitable for DeleteIndex and a key-scan to remove all storage. We assume only one index in this database, so delete everything.

func Key

func Key(index, field, view string, shard, roaringContainerKey uint64) (r []byte)

Key produces the bytes that we use as a key to query the storage/tx engine. The roaringContainerKey argument to Key() is a container key into a roaring Container. The return value from Key() is constructed as follows:

~field;view<ckey#

where ckey is always exactly 8 bytes, uint64 big-endian encoded.

Keys always start with either '~' or '>'. Keys always end with '#'. Keys always contain exactly one each of ';' and '<', in that order. The field is between the '~' and the ';'. It must be at least 1 byte long. The view is between the ';' and the '<'. It must be at least 1 byte long. The ckey is the 8 bytes between the '<' and the '#'. The Prefix of a key ends at, and includes, the '<'. It is at least 13 bytes long. The index, field, and view are not allowed to contain these reserved bytes:

{'~', '>', ';', ':', '<', '#', '$', '%', '^', '(', ')', '*', '!'}

The bytes {'+', '/', '-', '_', '.', and '=' can be used in index, field, and view; to enable base-64 encoding.

The shortest possible key is 14 bytes. It would be laid out like this:

~f;v<12345678#
12345678901234

keys starting with '~' are regular value keys. keys starting with '>' are symlink keys.

NB must be kept in sync with Prefix() and KeyExtractContainerKey().

func KeyAndPrefix

func KeyAndPrefix(index, field, view string, shard, roaringContainerKey uint64) (key, prefix []byte)

KeyAndPrefix returns the equivalent of Key() and Prefix() calls.

func KeyExtractContainerKey

func KeyExtractContainerKey(bkey []byte) (containerKey uint64)

KeyExtractContainerKey extracts the containerKey from bkey. key example: field;view<ckey shortest: ~f;v<12345678#

         1234567890123456789012345
numbering len(bkey) - i:
         5432109876543210987654321

func MustValidateKey

func MustValidateKey(bkey []byte)

func Prefix

func Prefix(index, field, view string, shard uint64) (r []byte)

Prefix returns everything from Key up to and including the '<' byte in a Key. The prefix excludes the roaring container key itself. NB must be kept in sync with Key() and KeyExtractContainerKey().

func PrefixFromKey

func PrefixFromKey(bkey []byte) (prefix []byte)

PrefixFromKey key example: ~field;view<ckey#

n-9    n-1

... : 01234567 < 01234567 #

view       ckey

func PrefixToString

func PrefixToString(pre []byte) (r string)

func Split

func Split(bkey []byte) (field, view string, ckey uint64)

func SplitPrefix

func SplitPrefix(pre []byte) (field, view string)

full key: ~field;view<ckey# prefix : ~field;view<

func ToString

func ToString(bkey []byte) (r string)

Types

type FieldView

type FieldView struct {
	Field string
	View  string
}

FieldView is here to avoid circular import.

func FieldViewFromFullKey

func FieldViewFromFullKey(fullKey []byte) FieldView

func FieldViewFromPrefix

func FieldViewFromPrefix(prefix []byte) FieldView