Welcome to the documentations of SWC-DB© !
SWC-DB© (Super Wide Column Database) - a High Performance Scalable Database
Introduction to the SWC-DB
The SWC-DB (Super Wide Column Database) a Super Fast database management system designed to handle Yottabytes+ on a quadrillion base of entries. SWC-DB latest-release is version 0.4.19 available at github.com/kashirin-alex/swc-db more details at Getting SWC-DB .
The proven test, on one machine(CPU Intel E3-1246V3 RAM 32GB SW-RAID 2x 2TB-7200rpm) run the DB and the Client, capabilities standing is a dozen terabytes of raw-data with 100+billion of record entries with performace input of ~250,000+ cells a second and random scan/select of one entry surrounds the microseconds to milliseconds, whereas performance varies on applied configurations and hardware. Testing facillity is required for in deep and further testing.
What is SWC-DB? checklist
|Is it?|| ||Comments|
|a Key Value DB|| |
|a Wide Column Database DB|| |
|a NOSQL (Not Only Structual Query Language) DB|| |
|a SQL (Structual Query Language) DB|| ||no joins|
|a DB with ACID(concept) for a single data-entry|| ||write with acknowledgment on base of one data-entry(cell)|
|a DB with ACID(concept) for a many data-entries|| ||write with acknowledgment many data-entries(cells) with one request, problem - one entry can exist while other yet to exist|
|a Relational DB|| ||achievable by the client-side|
|a Time Series DB|| ||without relational propotions|
|an Object Oriented DB|| ||binary key(Fractions) and value allowed, user defined Serialization IO or/and Serializations available with the SERIAL column-type|
|a XML DB / Tripel Stores|| ||require Native XML Client process XML-schema to Database structure|
|a Schema Free DB|| ||except to data/column type, schema/column-definition is without inner data schematics|
|a DB with User Concepts (Access Controls)|| |
|a Shard Partitioning DB|| |
|a Spatial DB|| ||user defined Fractions order and sequence in a Cell Key|
|a Variable Key Sequences DB|| ||infinite size (indefinite other limitation apply )|
|a Distributed + Scalable DB|| ||O(1) performance|
|a DB with Multihoming Capabilities|| |
|a DB with Nanosecond Precision|| |
|a DB supporting variety of File-Systems|| ||any File System which can implement the Base class SWC::FS::FileSystem|
|a DB with Data Replication Support|| ||File System dependant|
|a Versioned Data DB|| ||automatic or user defined versions by Desc/Asc with Max Versions to Keep|
|a DB supporting an “Atomic“ Counter Value|| |
|a DB supporting Query of Multiple Sequences|| ||multiple Columns with multiple Intervals in a Column|
|a Document/Files stores DB|| ||user defined Meta/Header & Key-Fractions(file-path) structure whereas anomaly of use is at file-size above Range-Block-size cfg|
|a Super Wide Column DB|| ||supporting 16777216(2^24,uint24) number of Fractions, max 2^24 bytes a Fraction and total size of a key upto 2^32 bytes|
|a DB with Communications over Secure Layer(SSL)|| ||The total security of transactions require the underlying configured FileSystem and Clients to have & support a Secure Layer|
The Differences of SWC-DB with Wide Column Databases
The major differences “Super Wide Column Database” has to commonly known Wide Column Databases are SWC-DB does not have Tables nor Namespaces and while cell key as known to be in Wide Column Database structured in timestamp, row, column-family and column-family-qualifier in SWC-DB a cell key is a list of Fractions with timestamp. The differences in SQL syntax, it is in-place of
select columns from “table_name” with SWC-DB It is
select [ where_clause [Columns-Intervals] ].
Considering to structure a Wide-Column-DB in SWC-DB it can be in these forms
key=[F(row), F(column-family), F(column-family-qualifier)] or the actual column is named after Namespace, Table and Column Family with
The Cell Key and Fractions in SWC-DB
The Fractions in SWC-DB cell-key let numerous “qualifiers”, as known to be, with a range-locator able to respond with the ranges applicable to the fractions of a scan specs. As a result a scan-spec of
key=[>“”, >=”THIS”] will scan ranges that consist the “THIS” on comparator with a help of metacolumn that include, additionally to the key-begin and key-end of a range, the minimal and maximum values of the fractions in an aligned manner. Hence the name “Super Wide Column“ a column can have cells with one key
[F(1st)] second key
[F(1st), F(2nd)] third key
[F(1st), F(2nd), F(3rd), .. ] and the scan/select is possible on
[F(1st)] and above that will return all the cells having fraction one equal “1st ” and so as without further indexations to select cells with key
[>F(), F(2nd)] returning the cells with second fraction equal “2nd”.
The Comparators in SWC-DB
The Comparators available in SWC-DB are NONE, PF ,GT, GE, EQ, LE, LT, NE, RE while some have limitations for range-locator as regexp is evaluated as NONE being anything-match. Additionally the conditions of comparators applied on the corresponding “ key-sequence ” by column's schema that include LEXIC, VOLUME, FC_LEXIC, FC_VOLUME that define the sequence of cells in a range. If a prefix (PF) is desired than the choice will be the LEXIC or with FC_LEXIC as VOLUME (volumetric) will not correspond to the char-byte sequence while if desired to have for example a decimal sequence of 0, 1, 2 .. 11 the VOLUME is the right choice whereas the FC_VOLUME unlike tree-wise on fraction keeps the sequence of smaller key fractions-count at the beginning in the range.
The Master Ranges and Meta Ranges in SWC-DB
SWC-DB use a self-explanatory master-ranges that define ranges to meta-ranges of data-ranges(cells-range) whereas on range-locator scan includes the Key comparison on the comparators of request, resulting in most narrowed ranges for the scan of cells. For the purpose SWC-DB have reserved columns
The Statistics column used for internal systems monitoring and it can be used like any other counter column (keeping for the purpose) with fraction of [period, role, instance, metric] with a counter value.
The Persistent Storage in SWC-DB
The storage-form in the SWC-DB on FS is based by column-id and range-id, that on path consist CellStores and CommitLog files while at any point one server is responsible for a range-id on column-id and of a path root. The CellStores are files storing Cells in serialized form that are after latest compaction whereas Commit-Log is Fragments of current added data, one fragment is written at a time on a threshold reach or on shutdown.
The limitations that can be overseen with SWC-DB
✗ Maximum number of columns, it is store-size of int64(264) – 10(reserved cols) which can be improved by CID to be a string-type.
✗ Maximum size of Value or Key-Fraction(after serialization), it is 4GB, while for such data size other limitations apply.
The capabilities to expect from SWC-DB
✔ A Manager-Root with definitions of 1K2 ranges (a use of 1 GB RAM) is a definition of 1K4 Meta-Ranges that sums-down to 1K8 Data-Ranges, with range-size configuration to 10GB that makes a total storage volume for a cell size average of 256KB to be a quarter of Yotta Byte.
✔ A client can read at 100%(while Client's and Ranger's are equivalent) bandwidth, considering a perfect scan case of each client is requesting on different ranges, number of clients at a given time can be by the number of data Rangers using 100% bandwidth each.
✔ Maximum number of concurrent connections to a given server instance, it is the total available ports on the server by the number of configured IPv4 and IPv6 with support of multi-homed / multiple interfaces.
The Failure Tolerance of SWC-DB
✔ A failed request to a Manager is a connection fail-over to next in list from ‘swc.mngr.host' configuration.
✔ A failed request to a Ranger(Master, Meta, Data)-N is a fail-over to the new newly assigned Ranger(addr) by Manager.
✔ Manager, on interval or shut-down state of a managed Ranger(either role), request to load ranges to another Ranger.
✔ Distribute File System, depends on the system and it's feature of routing to a datanode.
✔ Managers or Rangers in case of a connection or file-descriptor failure try to reconnect to the DFS.
✔ Communications security, SSL applicable between servers for non-secure networks.
✔ Communication over-heads of resolved-data of column-name, RID-location and Ranger-address are kept on TTL/KA. In worst case of outdated data being used with a request the Ranger return an error of a NOT_LOADED_RANGE.
The Documentations Table of Contents
- Introduction to the SWC-DB
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