Database storage engine

1. Islam Al Zatary
@islamzatary

2. 1. reliable units(recovery from failures and keep a
database consistent).
2. isolation between programs accessing a database
concurrently.
A database transaction, must be atomic, consistent, isolated and
durable.
ACID (atomicity, consistency, isolation, durability) is a set of
properties that guarantee database transactions are processed
reliably.

4. •Absence of transactions support.
Characteristics:
1. data values are stored with the low byte first.
2. All numeric key values are stored with the high byte first.
3. Large files (up to 63-bit file length).
4. There is a limit of 232 (~4.295E+09) rows in a MyISAM table.
5. The maximum number of indexes per MyISAM table is 64.
6. The maximum key length is 1000 bytes.
7. Internal handling of one AUTO_INCREMENT column per table is
supported.

5. 8. MyISAM supports concurrent inserts.
9. You can put the data file and index file in different directories on different
physical devices.
10. BLOB and TEXT columns can be indexed.
11. NULL values are allowed in indexed columns.
12. MyIsam, flags:
a. mysqld: indicates whether the table was closed correctly.
b. myisamchk: marks tables as checked if you run it with the --update-
state option.
c. myisamchk --analyze stores statistics for portions of keys, as well as
for entire keys.
d. myisampack can pack BLOB and VARCHAR columns.

6. * Transaction-safe (ACID compliant)
• stores user data in clustered indexes.
• supports FOREIGN KEY referential-integrity constraints.
• designed for maximum performance.
• large database sites requiring high performance,
Example: Slashdot.org
• stores more than 1TB of data and handles an average load
of 800 inserts/updates per second.
• increase multi-user concurrency and performance(row-
locking).

7. Stores all data in RAM for extremely fast access in
environments that require quick lookups of reference
and other like data. This engine was formerly known as
the HEAP engine.

8. Allows a MySQL DBA or developer to logically group a
series of identical MyISAM tables and reference them
as one object. Good for VLDB environments such as
data warehousing.

9. Provides the perfect solution for storing and retrieving
large amounts of seldom-referenced
historical, archived, or security audit information.

10. Offers the ability to link separate MySQL servers to
create one logical database from many physical servers.
Very good for distributed or data mart environments.

11. This clustered database engine is particularly suited for
applications that require the highest possible degree of
uptime and availability.

12. The CSV storage engine stores data in text files using
comma-separated values format. You can use the CSV
engine to easily exchange data between other software
and applications that can import and export in CSV
format.

13. The Blackhole storage engine accepts but does not
store data and retrievals always return an empty set.
The functionality can be used in distributed database
design where data is automatically replicated, but not
stored locally.

15. 1. Is your table is going to be inserted, deleted, and updated much
much more than it is going to be selected????
2. If you need full-text search?????
3. If you prefer/require relational database design?????
4. Is disk-space or ram an issue??????
5. In Doubt?????

17. Islam Al-Zatary - Front End Engineer
Twitter: islamzatary
Email: islamzatary@yahoo.com