ASCII Code - The extended ASCII table

 ASCII stands for American Standard Code for Information Interchange. It's a 7-bit character code where every single bit represents a unique character. On this webpage you will find 8 bits, 256 characters, according to ISO 8859-1 and Microsoft® Windows Latin-1 increased characters, which is available in certain programs such as Microsoft Word.


ASCII control characters (character code 0-31)

The first 32 characters in the ASCII-table are unprintable control codes and are used to control peripherals such as printers.
DECOCTHEXBINSymbolHTML NumberHTML NameDescription
00000000000000NUL� Null char
10010100000001SOH Start of Heading
20020200000010STX Start of Text
30030300000011ETX End of Text
40040400000100EOT End of Transmission
50050500000101ENQ Enquiry
60060600000110ACK Acknowledgment
70070700000111BEL Bell
80100800001000BS Back Space
90110900001001HT	 Horizontal Tab
100120A00001010LF
 Line Feed
110130B00001011VT Vertical Tab
120140C00001100FF Form Feed
130150D00001101CR
 Carriage Return
140160E00001110SO Shift Out / X-On
150170F00001111SI Shift In / X-Off
160201000010000DLE Data Line Escape
170211100010001DC1 Device Control 1 (oft. XON)
180221200010010DC2 Device Control 2
190231300010011DC3 Device Control 3 (oft. XOFF)
200241400010100DC4 Device Control 4
210251500010101NAK Negative Acknowledgement
220261600010110SYN Synchronous Idle
230271700010111ETB End of Transmit Block
240301800011000CAN Cancel
250311900011001EM End of Medium
260321A00011010SUB Substitute
270331B00011011ESC Escape
280341C00011100FS File Separator
290351D00011101GS Group Separator
300361E00011110RS Record Separator
310371F00011111US Unit Separator


ASCII printable characters (character code 32-127)

Codes 32-127 are common for all the different variations of the ASCII table, they are called printable characters, represent letters, digits, punctuation marks, and a few miscellaneous symbols. You will find almost every character on your keyboard. Character 127 represents the command DEL.
DECOCTHEXBINSymbolHTML NumberHTML NameDescription
320402000100000   Space
330412100100001!! Exclamation mark
340422200100010"""Double quotes (or speech marks)
350432300100011## Number
360442400100100$$ Dollar
370452500100101%% Procenttecken
380462600100110&&&Ampersand
390472700100111'' Single quote
400502800101000(( Open parenthesis (or open bracket)
410512900101001)) Close parenthesis (or close bracket)
420522A00101010** Asterisk
430532B00101011++ Plus
440542C00101100,, Comma
450552D00101101-- Hyphen
460562E00101110.. Period, dot or full stop
470572F00101111// Slash or divide
48060300011000000 Zero
49061310011000111 One
50062320011001022 Two
51063330011001133 Three
52064340011010044 Four
53065350011010155 Five
54066360011011066 Six
55067370011011177 Seven
56070380011100088 Eight
57071390011100199 Nine
580723A00111010:: Colon
590733B00111011;&#59; Semicolon
600743C00111100<&#60;&lt;Less than (or open angled bracket)
610753D00111101=&#61; Equals
620763E00111110>&#62;&gt;Greater than (or close angled bracket)
630773F00111111?&#63; Question mark
641004001000000@&#64; At symbol
651014101000001A&#65; Uppercase A
661024201000010B&#66; Uppercase B
671034301000011C&#67; Uppercase C
681044401000100D&#68; Uppercase D
691054501000101E&#69; Uppercase E
701064601000110F&#70; Uppercase F
711074701000111G&#71; Uppercase G
721104801001000H&#72; Uppercase H
731114901001001I&#73; Uppercase I
741124A01001010J&#74; Uppercase J
751134B01001011K&#75; Uppercase K
761144C01001100L&#76; Uppercase L
771154D01001101M&#77; Uppercase M
781164E01001110N&#78; Uppercase N
791174F01001111O&#79; Uppercase O
801205001010000P&#80; Uppercase P
811215101010001Q&#81; Uppercase Q
821225201010010R&#82; Uppercase R
831235301010011S&#83; Uppercase S
841245401010100T&#84; Uppercase T
851255501010101U&#85; Uppercase U
861265601010110V&#86; Uppercase V
871275701010111W&#87; Uppercase W
881305801011000X&#88; Uppercase X
891315901011001Y&#89; Uppercase Y
901325A01011010Z&#90; Uppercase Z
911335B01011011[&#91; Opening bracket
921345C01011100\&#92; Backslash
931355D01011101]&#93; Closing bracket
941365E01011110^&#94; Caret - circumflex
951375F01011111_&#95; Underscore
961406001100000`&#96; Grave accent
971416101100001a&#97; Lowercase a
981426201100010b&#98; Lowercase b
991436301100011c&#99; Lowercase c
1001446401100100d&#100; Lowercase d
1011456501100101e&#101; Lowercase e
1021466601100110f&#102; Lowercase f
1031476701100111g&#103; Lowercase g
1041506801101000h&#104; Lowercase h
1051516901101001i&#105; Lowercase i
1061526A01101010j&#106; Lowercase j
1071536B01101011k&#107; Lowercase k
1081546C01101100l&#108; Lowercase l
1091556D01101101m&#109; Lowercase m
1101566E01101110n&#110; Lowercase n
1111576F01101111o&#111; Lowercase o
1121607001110000p&#112; Lowercase p
1131617101110001q&#113; Lowercase q
1141627201110010r&#114; Lowercase r
1151637301110011s&#115; Lowercase s
1161647401110100t&#116; Lowercase t
1171657501110101u&#117; Lowercase u
1181667601110110v&#118; Lowercase v
1191677701110111w&#119; Lowercase w
1201707801111000x&#120; Lowercase x
1211717901111001y&#121; Lowercase y
1221727A01111010z&#122; Lowercase z
1231737B01111011{&#123; Opening brace
1241747C01111100|&#124; Vertical bar
1251757D01111101}&#125; Closing brace
1261767E01111110~&#126; Equivalency sign - tilde
1271777F01111111&#127; Delete


The extended ASCII codes (character code 128-255)

There are several different variations of the 8-bit ASCII table. The table below is according to ISO 8859-1, also called ISO Latin-1. Codes 129-159 contain the Microsoft® Windows Latin-1 extended characters.
DECOCTHEXBINSymbolHTML NumberHTML NameDescription
1282008010000000&#128;&euro;Euro sign
1292018110000001    
1302028210000010&#130;&sbquo;Single low-9 quotation mark
1312038310000011ƒ&#131;&fnof;Latin small letter f with hook
1322048410000100&#132;&bdquo;Double low-9 quotation mark
1332058510000101&#133;&hellip;Horizontal ellipsis
1342068610000110&#134;&dagger;Dagger
1352078710000111&#135;&Dagger;Double dagger
1362108810001000ˆ&#136;&circ;Modifier letter circumflex accent
1372118910001001&#137;&permil;Per mille sign
1382128A10001010Š&#138;&Scaron;Latin capital letter S with caron
1392138B10001011&#139;&lsaquo;Single left-pointing angle quotation
1402148C10001100Œ&#140;&OElig;Latin capital ligature OE
1412158D10001101    
1422168E10001110Ž&#142; Latin captial letter Z with caron
1432178F10001111    
1442209010010000    
1452219110010001&#145;&lsquo;Left single quotation mark
1462229210010010&#146;&rsquo;Right single quotation mark
1472239310010011&#147;&ldquo;Left double quotation mark
1482249410010100&#148;&rdquo;Right double quotation mark
1492259510010101&#149;&bull;Bullet
1502269610010110&#150;&ndash;En dash
1512279710010111&#151;&mdash;Em dash
1522309810011000˜&#152;&tilde;Small tilde
1532319910011001&#153;&trade;Trade mark sign
1542329A10011010š&#154;&scaron;Latin small letter S with caron
1552339B10011011&#155;&rsaquo;Single right-pointing angle quotation mark
1562349C10011100œ&#156;&oelig;Latin small ligature oe
1572359D10011101    
1582369E10011110ž&#158; Latin small letter z with caron
1592379F10011111Ÿ&#159;&yuml;Latin capital letter Y with diaeresis
160240A010100000 &#160;&nbsp;Non-breaking space
161241A110100001¡&#161;&iexcl;Inverted exclamation mark
162242A210100010¢&#162;&cent;Cent sign
163243A310100011£&#163;&pound;Pound sign
164244A410100100¤&#164;&curren;Currency sign
165245A510100101¥&#165;&yen;Yen sign
166246A610100110¦&#166;&brvbar;Pipe, Broken vertical bar
167247A710100111§&#167;&sect;Section sign
168250A810101000¨&#168;&uml;Spacing diaeresis - umlaut
169251A910101001©&#169;&copy;Copyright sign
170252AA10101010ª&#170;&ordf;Feminine ordinal indicator
171253AB10101011«&#171;&laquo;Left double angle quotes
172254AC10101100¬&#172;&not;Not sign
173255AD10101101&#173;&shy;Soft hyphen
174256AE10101110®&#174;&reg;Registered trade mark sign
175257AF10101111¯&#175;&macr;Spacing macron - overline
176260B010110000°&#176;&deg;Degree sign
177261B110110001±&#177;&plusmn;Plus-or-minus sign
178262B210110010²&#178;&sup2;Superscript two - squared
179263B310110011³&#179;&sup3;Superscript three - cubed
180264B410110100´&#180;&acute;Acute accent - spacing acute
181265B510110101µ&#181;&micro;Micro sign
182266B610110110&#182;&para;Pilcrow sign - paragraph sign
183267B710110111·&#183;&middot;Middle dot - Georgian comma
184270B810111000¸&#184;&cedil;Spacing cedilla
185271B910111001¹&#185;&sup1;Superscript one
186272BA10111010º&#186;&ordm;Masculine ordinal indicator
187273BB10111011»&#187;&raquo;Right double angle quotes
188274BC10111100¼&#188;&frac14;Fraction one quarter
189275BD10111101½&#189;&frac12;Fraction one half
190276BE10111110¾&#190;&frac34;Fraction three quarters
191277BF10111111¿&#191;&iquest;Inverted question mark
192300C011000000À&#192;&Agrave;Latin capital letter A with grave
193301C111000001Á&#193;&Aacute;Latin capital letter A with acute
194302C211000010Â&#194;&Acirc;Latin capital letter A with circumflex
195303C311000011Ã&#195;&Atilde;Latin capital letter A with tilde
196304C411000100Ä&#196;&Auml;Latin capital letter A with diaeresis
197305C511000101Å&#197;&Aring;Latin capital letter A with ring above
198306C611000110Æ&#198;&AElig;Latin capital letter AE
199307C711000111Ç&#199;&Ccedil;Latin capital letter C with cedilla
200310C811001000È&#200;&Egrave;Latin capital letter E with grave
201311C911001001É&#201;&Eacute;Latin capital letter E with acute
202312CA11001010Ê&#202;&Ecirc;Latin capital letter E with circumflex
203313CB11001011Ë&#203;&Euml;Latin capital letter E with diaeresis
204314CC11001100Ì&#204;&Igrave;Latin capital letter I with grave
205315CD11001101Í&#205;&Iacute;Latin capital letter I with acute
206316CE11001110Î&#206;&Icirc;Latin capital letter I with circumflex
207317CF11001111Ï&#207;&Iuml;Latin capital letter I with diaeresis
208320D011010000Ð&#208;&ETH;Latin capital letter ETH
209321D111010001Ñ&#209;&Ntilde;Latin capital letter N with tilde
210322D211010010Ò&#210;&Ograve;Latin capital letter O with grave
211323D311010011Ó&#211;&Oacute;Latin capital letter O with acute
212324D411010100Ô&#212;&Ocirc;Latin capital letter O with circumflex
213325D511010101Õ&#213;&Otilde;Latin capital letter O with tilde
214326D611010110Ö&#214;&Ouml;Latin capital letter O with diaeresis
215327D711010111×&#215;&times;Multiplication sign
216330D811011000Ø&#216;&Oslash;Latin capital letter O with slash
217331D911011001Ù&#217;&Ugrave;Latin capital letter U with grave
218332DA11011010Ú&#218;&Uacute;Latin capital letter U with acute
219333DB11011011Û&#219;&Ucirc;Latin capital letter U with circumflex
220334DC11011100Ü&#220;&Uuml;Latin capital letter U with diaeresis
221335DD11011101Ý&#221;&Yacute;Latin capital letter Y with acute
222336DE11011110Þ&#222;&THORN;Latin capital letter THORN
223337DF11011111ß&#223;&szlig;Latin small letter sharp s - ess-zed
224340E011100000à&#224;&agrave;Latin small letter a with grave
225341E111100001á&#225;&aacute;Latin small letter a with acute
226342E211100010â&#226;&acirc;Latin small letter a with circumflex
227343E311100011ã&#227;&atilde;Latin small letter a with tilde
228344E411100100ä&#228;&auml;Latin small letter a with diaeresis
229345E511100101å&#229;&aring;Latin small letter a with ring above
230346E611100110æ&#230;&aelig;Latin small letter ae
231347E711100111ç&#231;&ccedil;Latin small letter c with cedilla
232350E811101000è&#232;&egrave;Latin small letter e with grave
233351E911101001é&#233;&eacute;Latin small letter e with acute
234352EA11101010ê&#234;&ecirc;Latin small letter e with circumflex
235353EB11101011ë&#235;&euml;Latin small letter e with diaeresis
236354EC11101100ì&#236;&igrave;Latin small letter i with grave
237355ED11101101í&#237;&iacute;Latin small letter i with acute
238356EE11101110î&#238;&icirc;Latin small letter i with circumflex
239357EF11101111ï&#239;&iuml;Latin small letter i with diaeresis
240360F011110000ð&#240;&eth;Latin small letter eth
241361F111110001ñ&#241;&ntilde;Latin small letter n with tilde
242362F211110010ò&#242;&ograve;Latin small letter o with grave
243363F311110011ó&#243;&oacute;Latin small letter o with acute
244364F411110100ô&#244;&ocirc;Latin small letter o with circumflex
245365F511110101õ&#245;&otilde;Latin small letter o with tilde
246366F611110110ö&#246;&ouml;Latin small letter o with diaeresis
247367F711110111÷&#247;&divide;Division sign
248370F811111000ø&#248;&oslash;Latin small letter o with slash
249371F911111001ù&#249;&ugrave;Latin small letter u with grave
250372FA11111010ú&#250;&uacute;Latin small letter u with acute
251373FB11111011û&#251;&ucirc;Latin small letter u with circumflex
252374FC11111100ü&#252;&uuml;Latin small letter u with diaeresis
253375FD11111101ý&#253;&yacute;Latin small letter y with acute
254376FE11111110þ&#254;&thorn;Latin small letter thorn
255377FF11111111ÿ&#255;&yuml;Latin small letter y with diaeresis


The VLC media player not working (can not be run as root) | Backtrack 5


1. Open Konsole Terminal
2. Type
  cd /usr/bin/
  hexedit vlc
3. Press Tab -> Switch to ASCII
4. Press Ctrl+ S -> Search "geteuid"
Modify to "getppid"
5. Press Ctrl+ X -> Save


JavaScript - Example mm/dd/yyyy formatted dates | USA

// use a function for the exact format desired...
function MDYDateString(d){
  function pad(n){
    return n< 10? '0'+ n: n;
  }
  return pad(d.getUTCMonth()+ 1)+ '/'+ pad(d.getUTCDate())+ '/'+ d.getUTCFullYear();
}
// prints something like 12/20/2012
var d= new Date();
console.log(MDYDateString(d));

JavaScript - check starts with and ends with | test startsWith and endsWith

Add this functions to the String prototype:
if (typeof String.prototype.startsWith != 'function') {
  String.prototype.startsWith = function (str){
    return this.slice(0, str.length) == str;
  };
}
if (typeof String.prototype.endsWith != 'function') {
  String.prototype.endsWith = function (str){
    return this.slice(-str.length) == str;
  };
}
Then use it:
"Starts with JavaScript".startsWith("Starts"); // true
var foo= "Ends with JavaScript";
var bar= "JavaScript";
foo.startsWith(bar); // true

MySQL - ERROR 2002 (HY000): Can't connect to local MySQL server through socket | BackTrack 5

mysql -u root -p
****

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

mkdir /var/run/mysqld
touch /var/run/mysqld/mysqld.sock
chown -R mysql /var/run/mysqld
/etc/init.d/mysql restart



Google Chrome can not be run as root - BackTrack 5

Google Chrome can not be run as root.
Please start Google Chrome as a normal user. To run as root, you must specify an alternate --user-data-dir for storage of profile information.

1. Open Konsole Terminal

2. Type

  cd /opt/google/chrome/
  hexedit chrome

3. Press Tab -> Switch to ASCII

4. Press Ctrl+ S -> Search "geteuid"

  Modify to "getppid"

5. Press Ctrl+ X -> Save



Install Flash Player - BackTrack 5

  • As you may have noticed Flash Player does not work on Backtrack 5, so in order to fix this we first need to remove the current flash player by issuing the following commands:
root@bt:~# apt-get purge flashplugin-nonfree flashplugin-installer gnash gnash-common mozilla-plugin-gnash swfdec-mozilla
root@bt:~# rm -f /usr/lib/firefox/plugins/*flash*
root@bt:~# rm -f /usr/lib/firefox-addons/plugins/*flash*
root@bt:~# rm -f /usr/lib/mozilla/plugins/*flash*
root@bt:~# rm -f ~/.mozilla/plugins/*flash*so
root@bt:~# rm -rfd /usr/lib/nspluginwrapper
  • After removing flash we need to get the new flash player from the official website:
  1. Flash x64 ONLY FOR x64.
  2. Flash Player Download the .tar.gz file.
  • We will begin with Flash Square, SKIP THIS if you aren't using an x64 version of BackTrack.
root@bt:~# tar xvfz flashplayer10_2_p3_64bit_linux_111710.tar.gz
root@bt:~# chown root:root libflashplayer.so
root@bt:~# chmod 644 libflashplayer.so
root@bt:~# cp -f libflashplayer.so /usr/lib/mozilla/plugins/
root@bt:~# rm -rf libflashplayer.so
root@bt:~# ln -s /usr/lib/mozilla/plugins/libflashplayer.so /usr/lib/firefox/plugins/
  • Next up we will take care of the Flash Player:
root@bt:~# tar xvfz install_flash_player_10_linux.tar.gz
root@bt:~# mkdir ~/.mozilla/plugins
root@bt:~# mv -f libflashplayer.so ~/.mozilla/plugins/
root@bt:~# ln -s /usr/lib/mozilla/plugins/libflashplayer.so /usr/lib/firefox-addons/plugins/
root@bt:~# ln -s /usr/lib/mozilla/plugins/libflashplayer.so /usr/lib/xulrunner-addons/plugins/


  • We can test if flash player works over here.

Extract tar gz files (.tar.gz) - Linux command

Extract the vtigercrm-5.4.0.tar.gz archive file to /var/www/
tar xvfz vtigercrm-5.4.0.tar.gz -C /var/www/

More:
man tar

Top 1000 SQL Performance Tips - Top10SQLPerformanceTips

Interactive session from MySQL Camp I:
Specific Query Performance Tips (see also database design tips for tips on indexes):
  1. Use EXPLAIN to profile the query execution plan
  2. Use Slow Query Log (always have it on!)
  3. Don't use DISTINCT when you have or could use GROUP BY
  4. Insert performance
    1. Batch INSERT and REPLACE
    2. Use LOAD DATA instead of INSERT
  5. LIMIT m,n may not be as fast as it sounds. Learn how to improve it and read more about Efficient Pagination Using MySQL
  6. Don't use ORDER BY RAND() if you have > ~2K records
  7. Use SQL_NO_CACHE when you are SELECTing frequently updated data or large sets of data
  8. Avoid wildcards at the start of LIKE queries
  9. Avoid correlated subqueries and in select and where clause (try to avoid in)
  10. No calculated comparisons -- isolate indexed columns
  11. ORDER BY and LIMIT work best with equalities and covered indexes
  12. Separate text/blobs from metadata, don't put text/blobs in results if you don't need them
  13. Derived tables (subqueries in the FROM clause) can be useful for retrieving BLOBs without sorting them. (Self-join can speed up a query if 1st part finds the IDs and uses then to fetch the rest)
  14. ALTER TABLE...ORDER BY can take data sorted chronologically and re-order it by a different field -- this can make queries on that field run faster (maybe this goes in indexing?)
  15. Know when to split a complex query and join smaller ones
  16. Delete small amounts at a time if you can
  17. Make similar queries consistent so cache is used
  18. Have good SQL query standards
  19. Don't use deprecated features
  20. Turning OR on multiple index fields (<5.0) into UNION may speed things up (with LIMIT), after 5.0 the index_merge should pick stuff up.
  21. Don't use COUNT * on Innodb tables for every search, do it a few times and/or summary tables, or if you need it for the total # of rows, use SQL_CALC_FOUND_ROWS and SELECT FOUND_ROWS()
  22. Use INSERT ... ON DUPLICATE KEY update (INSERT IGNORE) to avoid having to SELECT
  23. use groupwise maximum instead of subqueries
  24. Avoid using IN(...) when selecting on indexed fields, It will kill the performance of SELECT query.
  25. Prefer using UNION ALL if you don't need to merge the result
Scaling Performance Tips:
  1. Use benchmarking
  2. isolate workloads don't let administrative work interfere with customer performance. (ie backups)
  3. Debugging sucks, testing rocks!
  4. As your data grows, indexing may change (cardinality and selectivity change). Structuring may want to change. Make your schema as modular as your code. Make your code able to scale. Plan and embrace change, and get developers to do the same.
Network Performance Tips:
  1. Minimize traffic by fetching only what you need.
    1. Paging/chunked data retrieval to limit
    2. Don't use SELECT *
    3. Be wary of lots of small quick queries if a longer query can be more efficient
  2. Use multi_query if appropriate to reduce round-trips
  3. Use stored procedures to avoid bandwidth wastage
OS Performance Tips:
  1. Use proper data partitions
    1. For Cluster. Start thinking about Cluster *before* you need them
  2. Keep the database host as clean as possible. Do you really need a windowing system on that server?
  3. Utilize the strengths of the OS
  4. pare down cron scripts
  5. create a test environment
  6. source control schema and config files
  7. for LVM innodb backups, restore to a different instance of MySQL so Innodb can roll forward
  8. partition appropriately
  9. partition your database when you have real data -- do not assume you know your dataset until you have real data
  10. Reduce swappiness of your OS
MySQL Server Overall Tips:
  1. innodb_flush_commit=0 can help slave lag
  2. Optimize for data types, use consistent data types. Use PROCEDURE ANALYSE() to help determine the smallest data type for your needs.
  3. use optimistic locking, not pessimistic locking. try to use shared lock, not exclusive lock. share mode vs. FOR UPDATE
  4. if you can, compress text/blobs
  5. compress static data
  6. don't back up static data as often
  7. enable and increase the query and buffer caches if appropriate
  8. config params -- http://docs.cellblue.nl/2007/03/17/easy-mysql-performance-tweaks/ is a good reference
  9. Config variables & tips:
    1. use one of the supplied config files
    2. key_buffer, unix cache (leave some RAM free), per-connection variables, innodb memory variables
    3. be aware of global vs. per-connection variables
    4. check SHOW STATUS and SHOW VARIABLES (GLOBAL|SESSION in 5.0 and up)
    5. be aware of swapping esp. with Linux, "swappiness" (bypass OS filecache for innodb data files, innodb_flush_method=O_DIRECT if possible (this is also OS specific))
    6. defragment tables, rebuild indexes, do table maintenance
    7. If you use innodb_flush_txn_commit=1, use a battery-backed hardware cache write controller
    8. more RAM is good so faster disk speed
    9. use 64-bit architectures
  10. --skip-name-resolve
  11. increase myisam_sort_buffer_size to optimize large inserts (this is a per-connection variable)
  12. look up memory tuning parameter for on-insert caching
  13. increase temp table size in a data warehousing environment (default is 32Mb) so it doesn't write to disk (also constrained by max_heap_table_size, default 16Mb)
  14. Run in SQL_MODE=STRICT to help identify warnings
  15. /tmp dir on battery-backed write cache
  16. consider battery-backed RAM for innodb logfiles
  17. use --safe-updates for client
  18. Redundant data is redundant
  19. Keep an eye on buffer pool and keybuffer hit rate
Storage Engine Performance Tips:
  1. InnoDB ALWAYS keeps the primary key as part of each index, so do not make the primary key very large
  2. Utilize different storage engines on master/slave ie, if you need fulltext indexing on a table.
  3. BLACKHOLE engine and replication is much faster than FEDERATED tables for things like logs.
  4. Know your storage engines and what performs best for your needs, know that different ones exist.
    1. ie, use MERGE tables ARCHIVE tables for logs
    2. Archive old data -- don't be a pack-rat! 2 common engines for this are ARCHIVE tables and MERGE tables
  5. use row-level instead of table-level locking for OLTP workloads
  6. try out a few schemas and storage engines in your test environment before picking one.
Database Design Performance Tips:
  1. Design sane query schemas. don't be afraid of table joins, often they are faster than denormalization
  2. Don't use boolean flags
  3. Use Indexes
  4. Don't Index Everything
  5. Do not duplicate indexes
  6. Do not use large columns in indexes if the ratio of SELECTs:INSERTs is low.
  7. Split out large blob elements in InnoDB
  8. be careful of redundant columns in an index or across indexes
  9. Use a clever key and ORDER BY instead of MAX
  10. Normalize first, and denormalize where appropriate.
  11. Databases are not spreadsheets, even though Access really really looks like one. Then again, Access isn't a real database
  12. use INET_ATON and INET_NTOA for IP addresses, not char or varchar
  13. make it a habit to REVERSE() email addresses, so you can easily search domains (this will help avoid wildcards at the start of LIKE queries if you want to find everyone whose e-mail is in a certain domain)
  14. A NULL data type can take more room to store than NOT NULL
  15. Avoid NULL in index attributes. Use 0 instead
  16. Storing flags in a database can slow down execution due to a bad cardinality. Try using bit flags
  17. Don't store flags in a NULL and NOT NULL manner. Update from NULL -> 1 is slower than 0 -> 1
  18. Choose appropriate character sets & collations -- UTF16 will store each character in 2 bytes, whether it needs it or not, latin1 is faster than UTF8.
  19. Use Triggers wisely
  20. Use delayed key wrote
  21. use min_rows and max_rows to specify approximate data size so space can be pre-allocated and reference points can be calculated.
  22. Use HASH indexing for indexing across columns with similar data prefixes
  23. Use myisam_pack_keys for int data
  24. be able to change your schema without ruining functionality of your code
  25. segregate tables/databases that benefit from different configuration variables
  26. Don't access the last key part in a where clause with =
  27. Abuse the system for optimiization you're using with system dependant features like RTREE's for optimized range queries
Other:
  1. Hire a MySQL (tm) Certified DBA
  2. Know that there are many consulting companies out there that can help, as well as MySQL's Professional Services.
  3. Read and post to MySQL Planet at http://www.planetmysql.org
  4. Attend the yearly MySQL Conference and Expo or other conferences with MySQL tracks (link to the conference here)
  5. Support your local User Group (link to forge page w/user groups here)

Authored by

Jay Pipes, Sheeri Kritzer, Bill Karwin, Ronald Bradford, Farhan "Frank Mash" Mashraqi, Taso Du Val, Ron Hu, Klinton Lee, Rick James, Alan Kasindorf, Eric Bergen, Robert Eisele, Kaj Arno, Joel Seligstein, Amy Lee, Sameer Joshi, Surat Singh Bhati

Where does Konqueror store its history, and how do I erase it?

There are several kinds of "history" stored by Konqueror.
  • The location bar combobox items and completion: you can clear those with right-click, "Clear History".
  • The history module in the sidebar: you can clear it with a right-click on one of the host names, and selecting "Clear History".
  • The HTTP cache (known as "Temporary Internet Files" in other environments) can be cleared in the KControl module called "Cache", using the "Clear cache" button on the bottom right.
 File locations (~/.kde is only an indication. Your distributor, or $KDEHOME, could have modified that value) :
  • Combobox items: ~/.kde/share/config/konq_history
  • History module and combobox completion: ~/.kde/share/apps/konqueror/konq_history (binary file)
  • HTTP cache: ~/.kde/share/cache/http/ (previously in ~/.kde/share/apps/kio_http/cache/)

JavaScript - Print Objects


JavaScript (sometimes abbreviated as JS) is a scripting language commonly implemented as part of a web browser in order to create enhanced user interfaces and dynamic websites.

JavaScript is a prototype-based scripting language that is dynamic, weakly typed and has first-class functions. It uses syntax influenced by the language C. JavaScript copies many names and naming conventions from Java, but the two languages are otherwise unrelated and have very different semantics. The key design principles within JavaScript are taken from the Self and Scheme programming languages. It is a multi-paradigm language, supporting object-oriented, imperative, and functional programming styles.

JavaScript's use in applications outside web pages — for example in PDF documents, site-specific browsers, and desktop widgets—is also significant. Newer and faster JavaScript VMs and frameworks built upon them (notably Node.js) have also increased the popularity of JavaScript for server-side web applications.

JavaScript was formalized in the ECMAScript language standard and is primarily used in the form of client-side JavaScript (as part of a web browser). This enables programmatic access to computational objects within a host environment.


// object
var userObj= {
    username: 'username',
    password: 'password'
}

// print
alert(userObj.toSource());

// or
for(attr in userObj){
    alert(attr+ '= '+ userObj[attr]);
}

console.log(userObj);