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  • How does the rsync algorithm correctly identify repeating blocks?

    - by Kai
    I'm on a personal quest to learn how the rsync algorithm works. After some reading and thinking, I've come up with a situation where I think the algorithm fails. I'm trying to figure out how this is resolved in an actual implementation. Consider this example, where A is the receiver and B is the sender. A = abcde1234512345fghij B = abcde12345fghij As you can see, the only change is that 12345 has been removed. Now, to make this example interesting, let's choose a block size of 5 bytes (chars). Hashing the values on the sender's side using the weak checksum gives the following values list. abcde|12345|fghij abcde -> 495 12345 -> 255 fghij -> 520 values = [495, 255, 520] Next we check to see if any hash values differ in A. If there's a matching block we can skip to the end of that block for the next check. If there's a non-matching block then we've found a difference. I'll step through this process. Hash the first block. Does this hash exist in the values list? abcde -> 495 (yes, so skip) Hash the second block. Does this hash exist in the values list? 12345 -> 255 (yes, so skip) Hash the third block. Does this hash exist in the values list? 12345 -> 255 (yes, so skip) Hash the fourth block. Does this hash exist in the values list? fghij -> 520 (yes, so skip) No more data, we're done. Since every hash was found in the values list, we conclude that A and B are the same. Which, in my humble opinion, isn't true. It seems to me this will happen whenever there is more than one block that share the same hash. What am I missing?

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  • IsNumeric() Broken? Only up to a point.

    - by Phil Factor
    In SQL Server, probably the best-known 'broken' function is poor ISNUMERIC() . The documentation says 'ISNUMERIC returns 1 when the input expression evaluates to a valid numeric data type; otherwise it returns 0. ISNUMERIC returns 1 for some characters that are not numbers, such as plus (+), minus (-), and valid currency symbols such as the dollar sign ($).'Although it will take numeric data types (No, I don't understand why either), its main use is supposed to be to test strings to make sure that you can convert them to whatever numeric datatype you are using (int, numeric, bigint, money, smallint, smallmoney, tinyint, float, decimal, or real). It wouldn't actually be of much use anyway, since each datatype has different rules. You actually need a RegEx to do a reasonably safe check. The other snag is that the IsNumeric() function  is a bit broken. SELECT ISNUMERIC(',')This cheerfully returns 1, since it believes that a comma is a currency symbol (not a thousands-separator) and you meant to say 0, in this strange currency.  However, SELECT ISNUMERIC(N'£')isn't recognized as currency.  '+' and  '-' is seen to be numeric, which is stretching it a bit. You'll see that what it allows isn't really broken except that it doesn't recognize Unicode currency symbols: It just tells you that one numeric type is likely to accept the string if you do an explicit conversion to it using the string. Both these work fine, so poor IsNumeric has to follow suit. SELECT  CAST('0E0' AS FLOAT)SELECT  CAST (',' AS MONEY) but it is harder to predict which data type will accept a '+' sign. SELECT  CAST ('+' AS money) --0.00SELECT  CAST ('+' AS INT)   --0SELECT  CAST ('+' AS numeric)/* Msg 8115, Level 16, State 6, Line 4 Arithmetic overflow error converting varchar to data type numeric.*/SELECT  CAST ('+' AS FLOAT)/*Msg 8114, Level 16, State 5, Line 5Error converting data type varchar to float.*/> So we can begin to say that the maybe IsNumeric isn't really broken, but is answering a silly question 'Is there some numeric datatype to which i can convert this string? Almost, but not quite. The bug is that it doesn't understand Unicode currency characters such as the euro or franc which are actually valid when used in the CAST function. (perhaps they're delaying fixing the euro bug just in case it isn't necessary).SELECT ISNUMERIC (N'?23.67') --0SELECT  CAST (N'?23.67' AS money) --23.67SELECT ISNUMERIC (N'£100.20') --1SELECT  CAST (N'£100.20' AS money) --100.20 Also the CAST function itself is quirky in that it cannot convert perfectly reasonable string-representations of integers into integersSELECT ISNUMERIC('200,000')       --1SELECT  CAST ('200,000' AS INT)   --0/*Msg 245, Level 16, State 1, Line 2Conversion failed when converting the varchar value '200,000' to data type int.*/  A more sensible question is 'Is this an integer or decimal number'. This cuts out a lot of the apparent quirkiness. We do this by the '+E0' trick. If we want to include floats in the check, we'll need to make it a bit more complicated. Here is a small test-rig. SELECT  PossibleNumber,         ISNUMERIC(CAST(PossibleNumber AS NVARCHAR(20)) + 'E+00') AS Hack,        ISNUMERIC (PossibleNumber + CASE WHEN PossibleNumber LIKE '%E%'                                          THEN '' ELSE 'E+00' END) AS Hackier,        ISNUMERIC(PossibleNumber) AS RawIsNumericFROM    (SELECT CAST(',' AS NVARCHAR(10)) AS PossibleNumber          UNION SELECT '£' UNION SELECT '.'         UNION SELECT '56' UNION SELECT '456.67890'         UNION SELECT '0E0' UNION SELECT '-'         UNION SELECT '-' UNION SELECT '.'         UNION  SELECT N'?' UNION SELECT N'¢'        UNION  SELECT N'?' UNION SELECT N'?34.56'         UNION SELECT '-345' UNION SELECT '3.332228E+09') AS examples Which gives the result ... PossibleNumber Hack Hackier RawIsNumeric-------------- ----------- ----------- ------------? 0 0 0- 0 0 1, 0 0 1. 0 0 1¢ 0 0 1£ 0 0 1? 0 0 0?34.56 0 0 00E0 0 1 13.332228E+09 0 1 1-345 1 1 1456.67890 1 1 156 1 1 1 I suspect that this is as far as you'll get before you abandon IsNumeric in favour of a regex. You can only get part of the way with the LIKE wildcards, because you cannot specify quantifiers. You'll need full-blown Regex strings like these ..[-+]?\b[0-9]+(\.[0-9]+)?\b #INT or REAL[-+]?\b[0-9]{1,3}\b #TINYINT[-+]?\b[0-9]{1,5}\b #SMALLINT.. but you'll get even these to fail to catch numbers out of range.So is IsNumeric() an out and out rogue function? Not really, I'd say, but then it would need a damned good lawyer.

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  • Working with a large data object between ruby processes

    - by Gdeglin
    I have a Ruby hash that reaches approximately 10 megabytes if written to a file using Marshal.dump. After gzip compression it is approximately 500 kilobytes. Iterating through and altering this hash is very fast in ruby (fractions of a millisecond). Even copying it is extremely fast. The problem is that I need to share the data in this hash between Ruby on Rails processes. In order to do this using the Rails cache (file_store or memcached) I need to Marshal.dump the file first, however this incurs a 1000 millisecond delay when serializing the file and a 400 millisecond delay when serializing it. Ideally I would want to be able to save and load this hash from each process in under 100 milliseconds. One idea is to spawn a new Ruby process to hold this hash that provides an API to the other processes to modify or process the data within it, but I want to avoid doing this unless I'm certain that there are no other ways to share this object quickly. Is there a way I can more directly share this hash between processes without needing to serialize or deserialize it? Here is the code I'm using to generate a hash similar to the one I'm working with: @a = [] 0.upto(500) do |r| @a[r] = [] 0.upto(10_000) do |c| if rand(10) == 0 @a[r][c] = 1 # 10% chance of being 1 else @a[r][c] = 0 end end end @c = Marshal.dump(@a) # 1000 milliseconds Marshal.load(@c) # 400 milliseconds Update: Since my original question did not receive many responses, I'm assuming there's no solution as easy as I would have hoped. Presently I'm considering two options: Create a Sinatra application to store this hash with an API to modify/access it. Create a C application to do the same as #1, but a lot faster. The scope of my problem has increased such that the hash may be larger than my original example. So #2 may be necessary. But I have no idea where to start in terms of writing a C application that exposes an appropriate API. A good walkthrough through how best to implement #1 or #2 may receive best answer credit.

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  • WPF data-bound ComboBox only shows first item of ItemsSource list

    - by Mark
    Hi all, I'm sure I'm doing something stupid but for the life of me I can't think of right now. I have a ComboBox that is data-bound to a list of Layout objects. The list is initially empty but things are added over time. When the list is updated by the model the first time, this update reflects properly in the ComboBox. However, subsequent updates never show up in the ComboBox even though I can see that the list itself contains these items. Since the first update works, I know the data-binding is OK - so what am I doing wrong here? Here's the XAML (abridged): <Grid HorizontalAlignment="Stretch"> <ComboBox ItemsSource="{Binding Path=SavedLayouts, diagnostics:PresentationTraceSources.TraceLevel=High}" DisplayMemberPath="Name" SelectedValuePath="Name" SelectedItem="{Binding LoadLayout}" Height="25" Grid.Row="1" Grid.Column="0"></ComboBox> </Grid> And the related part of the model: public IList<Layout> SavedLayouts { get { return _layouts; } } public Layout SaveLayout( String data_ ) { Layout theLayout = new Layout( SaveLayoutName ); _layouts.Add( theLayout ); try { return theLayout; } finally { PropertyChangedEventHandler handler = PropertyChanged; if( handler != null ) { handler( this, new PropertyChangedEventArgs( "SavedLayouts" ) ); } } } And finally, the layout class (abridged): public class Layout { public String Name { get; private set; } } In the output window, I can see the update occurring: System.Windows.Data Warning: 91 : BindingExpression (hash=64564967): Got PropertyChanged event from TickerzModel (hash=43624632) System.Windows.Data Warning: 97 : BindingExpression (hash=64564967): GetValue at level 0 from TickerzModel (hash=43624632) using RuntimePropertyInfo(SavedLayouts): List`1 (hash=16951421 Count=11) System.Windows.Data Warning: 76 : BindingExpression (hash=64564967): TransferValue - got raw value List`1 (hash=16951421 Count=11) System.Windows.Data Warning: 85 : BindingExpression (hash=64564967): TransferValue - using final value List`1 (hash=16951421 Count=11) But I get do not get this 11th item in the ComboBox. Any ideas?

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  • Issue with creating index organized table

    - by mtim
    I'm having a weird problem with index organized table. I'm running Oracle 11g standard. i have a table src_table SQL> desc src_table; Name Null? Type --------------- -------- ---------------------------- ID NOT NULL NUMBER(16) HASH NOT NULL NUMBER(3) ........ SQL> select count(*) from src_table; COUNT(*) ---------- 21108244 now let's create another table and copy 2 columns from src_table set timing on SQL> create table dest_table(id number(16), hash number(20), type number(1)); Table created. Elapsed: 00:00:00.01 SQL> insert /*+ APPEND */ into dest_table (id,hash,type) select id, hash, 1 from src_table; 21108244 rows created. Elapsed: 00:00:15.25 SQL> ALTER TABLE dest_table ADD ( CONSTRAINT dest_table_pk PRIMARY KEY (HASH, id, TYPE)); Table altered. Elapsed: 00:01:17.35 It took Oracle < 2 min. now same exercise but with IOT table SQL> CREATE TABLE dest_table_iot ( id NUMBER(16) NOT NULL, hash NUMBER(20) NOT NULL, type NUMBER(1) NOT NULL, CONSTRAINT dest_table_iot_PK PRIMARY KEY (HASH, id, TYPE) ) ORGANIZATION INDEX; Table created. Elapsed: 00:00:00.03 SQL> INSERT /*+ APPEND */ INTO dest_table_iot (HASH,id,TYPE) SELECT HASH, id, 1 FROM src_table; "insert" into IOT takes 18 hours !!! I have tried it on 2 different instances of Oracle running on win and linux and got same results. What is going on here ? Why is it taking so long ?

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  • postfix with mailman

    - by Thufir
    What should happen is that [email protected] should be delivered to that users inbox on localhost, user@localhost. Thunderbird works fine at reading user@localhost. I'm just using a small portion of postfix-dovecot with Ubuntu mailman. How can I get postfix to recognize the FQDN and deliver them to a localhost inbox? root@dur:~# root@dur:~# tail /var/log/mail.err;tail /var/log/mailman/subscribe;postconf -n Aug 27 18:59:16 dur dovecot: lda(root): Error: chdir(/root) failed: Permission denied Aug 27 18:59:16 dur dovecot: lda(root): Error: user root: Initialization failed: Initializing mail storage from mail_location setting failed: stat(/root/Maildir) failed: Permission denied (euid=65534(nobody) egid=65534(nogroup) missing +x perm: /root, dir owned by 0:0 mode=0700) Aug 27 18:59:16 dur dovecot: lda(root): Fatal: Invalid user settings. Refer to server log for more information. Aug 27 20:09:16 dur postfix/trivial-rewrite[15896]: error: open database /etc/postfix/transport.db: No such file or directory Aug 27 21:19:17 dur postfix/trivial-rewrite[16569]: error: open database /etc/postfix/transport.db: No such file or directory Aug 27 22:27:00 dur postfix[17042]: fatal: usage: postfix [-c config_dir] [-Dv] command Aug 27 22:29:19 dur postfix/trivial-rewrite[17062]: error: open database /etc/postfix/transport.db: No such file or directory Aug 27 22:59:07 dur postfix/postfix-script[17459]: error: unknown command: 'restart' Aug 27 22:59:07 dur postfix/postfix-script[17460]: fatal: usage: postfix start (or stop, reload, abort, flush, check, status, set-permissions, upgrade-configuration) Aug 27 23:39:17 dur postfix/trivial-rewrite[17794]: error: open database /etc/postfix/transport.db: No such file or directory Aug 27 21:39:03 2012 (16734) cola: pending "[email protected]" <[email protected]> 127.0.0.1 Aug 27 21:40:37 2012 (16749) cola: pending "[email protected]" <[email protected]> 127.0.0.1 Aug 27 22:45:31 2012 (17288) gmane.mail.mailman.user.1: pending [email protected] 127.0.0.1 Aug 27 22:45:46 2012 (17293) gmane.mail.mailman.user.1: pending [email protected] 127.0.0.1 Aug 27 23:02:01 2012 (17588) test3: pending [email protected] 127.0.0.1 Aug 27 23:05:41 2012 (17652) test4: pending [email protected] 127.0.0.1 Aug 27 23:56:20 2012 (17985) test5: pending [email protected] 127.0.0.1 alias_database = hash:/etc/aliases alias_maps = hash:/etc/aliases, hash:/var/lib/mailman/data/aliases append_dot_mydomain = no biff = no broken_sasl_auth_clients = yes config_directory = /etc/postfix default_transport = smtp home_mailbox = Maildir/ inet_interfaces = loopback-only mailbox_command = /usr/lib/dovecot/deliver -c /etc/dovecot/conf.d/01-mail-stack-delivery.conf -m "${EXTENSION}" mailbox_size_limit = 0 mailman_destination_recipient_limit = 1 mydestination = dur, dur.bounceme.net, localhost.bounceme.net, localhost myhostname = dur.bounceme.net mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 readme_directory = no recipient_delimiter = + relay_domains = lists.dur.bounceme.net relay_transport = relay relayhost = smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache smtp_use_tls = yes smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu) smtpd_recipient_restrictions = reject_unknown_sender_domain, reject_unknown_recipient_domain, reject_unauth_pipelining, permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination smtpd_sasl_auth_enable = yes smtpd_sasl_authenticated_header = yes smtpd_sasl_local_domain = $myhostname smtpd_sasl_path = private/dovecot-auth smtpd_sasl_security_options = noanonymous smtpd_sasl_type = dovecot smtpd_tls_auth_only = yes smtpd_tls_cert_file = /etc/ssl/certs/ssl-mail.pem smtpd_tls_key_file = /etc/ssl/private/ssl-mail.key smtpd_tls_mandatory_ciphers = medium smtpd_tls_mandatory_protocols = SSLv3, TLSv1 smtpd_tls_received_header = yes smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache smtpd_use_tls = yes tls_random_source = dev:/dev/urandom transport_maps = hash:/etc/postfix/transport root@dur:~# there's definitely a transport problem: root@dur:~# root@dur:~# root@dur:~# grep transport /var/log/mail.log | tail Aug 27 22:29:19 dur postfix/trivial-rewrite[17062]: warning: hash:/etc/postfix/transport lookup error for "[email protected]" Aug 27 22:29:19 dur postfix/trivial-rewrite[17062]: warning: transport_maps lookup failure Aug 27 23:39:17 dur postfix/trivial-rewrite[17794]: error: open database /etc/postfix/transport.db: No such file or directory Aug 27 23:39:17 dur postfix/trivial-rewrite[17794]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Aug 27 23:39:17 dur postfix/trivial-rewrite[17794]: warning: hash:/etc/postfix/transport lookup error for "*" Aug 27 23:39:17 dur postfix/trivial-rewrite[17794]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Aug 27 23:39:17 dur postfix/trivial-rewrite[17794]: warning: hash:/etc/postfix/transport lookup error for "*" Aug 27 23:39:17 dur postfix/trivial-rewrite[17794]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Aug 27 23:39:17 dur postfix/trivial-rewrite[17794]: warning: hash:/etc/postfix/transport lookup error for "[email protected]" Aug 27 23:39:17 dur postfix/trivial-rewrite[17794]: warning: transport_maps lookup failure root@dur:~# trying to add the transport file: EDIT root@dur:~# root@dur:~# touch /etc/postfix/transport root@dur:~# ll /etc/postfix/transport -rw-r--r-- 1 root root 0 Aug 28 00:16 /etc/postfix/transport root@dur:~# root@dur:~# cd /etc/postfix/ root@dur:/etc/postfix# root@dur:/etc/postfix# postmap transport root@dur:/etc/postfix# root@dur:/etc/postfix# cat transport

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  • what is the purpose of numeric/boolean/string objects as opposed to primitive values?

    - by zespri
    In javascript you can call a function as a function or as a constructor. For example you can do : myObject = new Number(13); myPrimitiveValue = Number(13); or simply myPrimitiveValue = 13; I understand the difference between the results. Can you explain me under which reasonable circumstances creating a number, a boolean or a string as an object is desirable? For example, ability to set new properties (this is something you can do on objects but can't really do on primitive values) is almost always a bad idea for objects containing number/boolean/string. Why would I want a numeric/boolean/string object?

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  • Find consecutive sub-vectors of length k out of a numeric vector which satisfy a given condition

    - by user3559153
    I have a numeric vector in R, say v= c(2,3,5,6,7,6,3,2,3,4,5,7,8,9,6,1,1,2,5,6,7,11,2,3,4). Now, I have to find all the consecutive sub-vector of size 4 out of it with the condition that each element of the sub-vector must be greater than 2 and all sub-vector must be disjoint in the sense that non of the two sub-vector can contain same index element. So my output will be: (3,5,6,7),(3,4,5,7),(5,6,7,11). [Explanation: c(2,3,5,6,7,6,3,2,3,4,5,7,8,9,6,1,3,2,5,6,7,11,2,3,4) ]

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  • Tracking unique versions of files with hashes

    - by rwmnau
    I'm going to be tracking different versions of potentially millions of different files, and my intent is to hash them to determine I've already seen that particular version of the file. Currently, I'm only using MD5 (the product is still in development, so it's never dealt with millions of files yet), which is clearly not long enough to avoid collisions. However, here's my question - Am I more likely to avoid collisions if I hash the file using two different methods and store both hashes (say, SHA1 and MD5), or if I pick a single, longer hash (like SHA256) and rely on that alone? I know option 1 has 288 hash bits and option 2 has only 256, but assume my two choices are the same total hash length. Since I'm dealing with potentially millions of files (and multiple versions of those files over time), I'd like to do what I can to avoid collisions. However, CPU time isn't (completely) free, so I'm interested in how the community feels about the tradeoff - is adding more bits to my hash proportionally more expensive to compute, and are there any advantages to multiple different hashes as opposed to a single, longer hash, given an equal number of bits in both solutions?

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  • Is it an MD5 digest in this Python script?

    - by brilliant
    Hello, I am trying to understand this simple hashlib code in Python that has been given to me the other day on "Stackoverflow": import hashlib m = hashlib.md5() m.update("Nobody inspects") m.update(" the spammish repetition here") m.digest() '\xbbd\x9c\x83\xdd\x1e\xa5\xc9\xd9\xde\xc9\xa1\x8d\xf0\xff\xe9' m.digest_size 16 m.block_size 64 print m I thought that "print m" would show me the MD5 digest of the phrase: "Nobody inspects the spammish repetition here", but as a result I got this line on my local host: <md5 HASH object @ 01806220> Strange, when I refreshed the page, I got another line: <md5 HASH object @ 018062E0> and every time when I refresh it, I get another value: md5 HASH object @ 017F8AE0 md5 HASH object @ 01806220 md5 HASH object @ 01806360 md5 HASH object @ 01806400 md5 HASH object @ 01806220 Why is it so? I guess, what I have in each line flowing "@" is not really a digest. Then, what is it? And how can I display MD5 digest here in this code? My python version is Python 2.5 and the framework I am currently using is webapp (I have downloaded it together with SDK from "Google App Engine")

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  • Help using Horner's rule and Hash Functions in JAVA?

    - by Matt
    I am trying to use Horner's rule to convert words to integers. I understand how it works and how if the word is long, it may cause an overflow. My ultimate goal is to use the converted integer in a hash function h(x)=x mod tableSize. My book suggests, because of the overflow, you could "apply the mod operator after computing each parenthesized expression in Horner's rule." I don't exactly understand what they mean by this. Say the expression looks like this: ((14*32+15)*32+20)*32+5 Do I take the mod tableSize after each parenthesized expression and add them together? What would it look like with this hash function and this example of Horner's rule?

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  • How can I accept a hash mark in a URL via $_GET?

    - by bccarlso
    From what I have been able to understand, hash marks (#) aren't sent to the server, so it doesn't seem likely that I will be able to use raw PHP to parse data like in the URL below: index.php?name=Ben&address=101 S 10th St Suite #301 I'm looking to pre-populate form fields with this $_GET data. How would I do this with Javascript (or jQuery), and is there a fallback that wouldn't break my form for people not using Javascript? Currently if there is a hash (usually in the address field), everything after that is not parsed in or stored in $_GET.

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  • How can I generate a unique ID using a hash in Perl?

    - by sganesh
    I doing message transfer program between multiple clients and server. I want to generate unique message id for every messages. that should be generated by server and return to client. For message transfer I am using hash data structure, Ex: { api => POST, username => sganesh, pass => "pass", message => "hai", time => "current_time", } I want to generate unique id using this hash. I have tried some of the ways, MD5 and freeze but this give unreadable id. I want some meaningful or readable unique id. I have thought we can use micro seconds to differentiate the id but here the problem is multiple clients. In any situation my id should be unique. Can anyone help me out of this problem? Thanks in Advance.

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  • Why is Postgres doing a Hash in this query?

    - by Claudiu
    I have two tables: A and P. I want to get information out of all rows in A whose id is in a temporary table I created, tmp_ids. However, there is additional information about A in the P table, foo, and I want to get this info as well. I have the following query: SELECT A.H_id AS hid, A.id AS aid, P.foo, A.pos, A.size FROM tmp_ids, P, A WHERE tmp_ids.id = A.H_id AND P.id = A.P_id I noticed it going slowly, and when I asked Postgres to explain, I noticed that it combines tmp_ids with an index on A I created for H_id with a nested loop. However, it hashes all of P before doing a Hash join with the result of the first merge. P is quite large and I think this is what's taking all the time. Why would it create a hash there? P.id is P's primary key, and A.P_id has an index of its own.

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  • Python: What's a correct and good way to implement __hash__()?

    - by random-name
    What's a correct and good way to implement hash()? I am talking about the function that returns a hashcode that is then used to insert objects into hashtables aka dictionaries. As hash() returns an integer and is used for "binning" objects into hashtables I assume that the values of the returned integer should be uniformly distributed for common data (to minimize collisions). What's a good practice to get such values? Are collisions a problem? In my case I have a small class which acts as a container class holding some ints, some floats and a string.

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  • Can I use a single pointer for my hash table in C?

    - by aks
    I want to implement a hash table in the following manner: struct list { char *string; struct list *next; }; struct hash_table { int size; /* the size of the table */ struct list **table; /* the table elements */ }; Instead of struct hash_table like above, can I use: struct hash_table { int size; /* the size of the table */ struct list *table; /* the table elements */ }; That is, can I just use a single pointer instead of a double pointer for the hash table elements? If yes, please explain the difference in the way the elements will be stored in the table?

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  • How do I use Spreadsheet::WriteExcel to create a chart from numeric log data?

    - by yaohung
    I used csv2xls.pl to convert a text log into .xls format, and then I create a chart as in the following: my $chart3 = $workbook->add_chart( type => 'line' , embedded => 1); # Configure the series. $chart3->add_series( categories => '=Sheet1!$B$2:$B$64', values => '=Sheet1!$C$2:$C$64', name => 'Test data series 1', ); # Add some labels. $chart3->set_title( name => 'Bridge Rate Analysis' ); $chart3->set_x_axis( name => 'Packet Size ' ); $chart3->set_y_axis( name => 'BVI Rate' ); # Insert the chart into the main worksheet. $worksheet->insert_chart( 'G2', $chart3 ); I can see the chart in the .xls file. However, all the data are in text format, not numeric, so the chart looks wrong. How do I convert text into number before applying this create-chart function? Also, how do I sort the .xls file before creating the chart?

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  • What hash should be used to ensure file integrity?

    - by Corey Ogburn
    It's no secret that large files offered up for download often are coupled with their MD5 or SHA-1 hash so that after you download you can verify the file's integrity. Are these still the best algorithms to use for this? Obviously these are very popular hashes that potential downloaders would have easy access to. Ignoring that factor, what hashes have the best properties for being used for this? For example, bcrypt would be horrible for this. It's designed to be slow. That would suck to use on your 7.4 GB dual layer OS ISO you just downloaded when a 12 letter password might take up to a second with the right parameters.

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  • Migrating Identity Providers - specifying a new users password hash.

    - by Stephen Denne
    We'd like to switch Identity Provider (and Web Access Manager), and also the user directory we use, but would like to do so without users needing to change their password. We currently have the SSHA of the passwords. I'm expecting to write code to perform the migration. I don't mind how complex the code has to be, rather my concern is whether such a migration is possible at all. MS Active Directory would be our preferred user store, but I believe that it can not have new users set up in it with a particular password hash. Is that correct? What user directory stores can be populated with users already set up with a SSHA password? What Identity Provider and Access Management products work with those stores?

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  • is it right to call ejb bean from thread by ThreadPoolExecutor?

    - by kislo_metal
    I trying to call some ejb bean method from tread. and getting error : (as is glassfish v3) Log Level SEVERE Logger javax.enterprise.system.std.com.sun.enterprise.v3.services.impl Name-Value Pairs {_ThreadName=Thread-1, _ThreadID=42} Record Number 928 Message ID java.lang.NullPointerException at ua.co.rufous.server.broker.TempLicService.run(TempLicService.java Complete Message 35) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:637) here is tread public class TempLicService implements Runnable { String hash; //it`s Stateful bean @EJB private LicActivatorLocal lActivator; public TempLicService(String hash) { this.hash= hash; } @Override public void run() { lActivator.proccessActivation(hash); } } my ThreadPoolExecutor public class RequestThreadPoolExecutor extends ThreadPoolExecutor { private boolean isPaused; private ReentrantLock pauseLock = new ReentrantLock(); private Condition unpaused = pauseLock.newCondition(); private static RequestThreadPoolExecutor threadPool; private RequestThreadPoolExecutor() { super(1, Integer.MAX_VALUE, 10, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>()); System.out.println("RequestThreadPoolExecutor created"); } public static RequestThreadPoolExecutor getInstance() { if (threadPool == null) threadPool = new RequestThreadPoolExecutor(); return threadPool; } public void runService(Runnable task) { threadPool.execute(task); } protected void beforeExecute(Thread t, Runnable r) { super.beforeExecute(t, r); pauseLock.lock(); try { while (isPaused) unpaused.await(); } catch (InterruptedException ie) { t.interrupt(); } finally { pauseLock.unlock(); } } public void pause() { pauseLock.lock(); try { isPaused = true; } finally { pauseLock.unlock(); } } public void resume() { pauseLock.lock(); try { isPaused = false; unpaused.signalAll(); } finally { pauseLock.unlock(); } } public void shutDown() { threadPool.shutdown(); } //<<<<<< creating thread here public void runByHash(String hash) { Runnable service = new TempLicService(hash); threadPool.runService(service); } } and method where i call it (it is gwt servlet, but there is no proble to call thread that not contain ejb) : @Override public Boolean submitHash(String hash) { System.out.println("submiting hash"); try { if (tBoxService.getTempLicStatus(hash) == 1) { //<<< here is the call RequestThreadPoolExecutor.getInstance().runByHash(hash); return true; } } catch (NoResultException e) { e.printStackTrace(); } return false; } I need to organize some pool of submitting hash to server (calls of LicActivator bean), is ThreadPoolExecutor design good idea and why it is not working in my case? (as I know we can`t create thread inside bean, but could we call bean from different threads? ). If No, what is the bast practice for organize such request pool? Thanks. << Answer: I am using DI (EJB 3.1) soo i do not need any look up here. (application packed in ear and both modules in it (web module and ejb), it works perfect for me). But I can use it only in managed classes. So.. 2.Can I use manual look up in Tread ? Could I use Bean that extends ThreadPoolExecutor and calling another bean that implements Runnable ? Or it is not allowed ?

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  • How can I rank teams based off of head to head wins/losses

    - by TMP
    I'm trying to write an algorithm (specifically in Ruby) that will rank teams based on their record against each other. If a team A and team B have won the same amount of games against each other, then it goes down to point differentials. Here's an example: A beat B two times B beats C one time A beats D three times C bests D two times D beats C one time B beats A one time Which sort of reduces to A[B] = 2 B[C] = 1 A[D] = 3 C[D] = 2 D[C] = 1 B[A] = 1 Which sort of reduces to A[B] = 1 B[C] = 1 A[D] = 3 C[D] = 1 D[C] = -1 B[A] = -1 Which is about how far I've got I think the results of this specific algorithm would be: A, B, C, D But I'm stuck on how to transition from my nested hash-like structure to the results. My psuedo-code is as follows (I can post my ruby code too if someone wants): For each game(g): hash[g.winner][g.loser] += 1 That leaves hash as the first reduction above hash2 = clone of hash For each key(winner), value(losers hash) in hash: For each key(loser), value(losses against winner): hash2[loser][winner] -= losses Which leaves hash2 as the second reduction Feel free to as me question or edit this to be more clear, I'm not sure of how to put it in a very eloquent way. Thanks!

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  • Best Practice: What can be the hashCode() method implementation if custom field used in equals() method are null?

    - by goodspeed
    What is the best practice to return a value for hashCode() method if custom field used in equals are null ? I have a situation, where equals() override is implemented using custom fields. Usually it it is better to override hashCode() also using that custom fields used in equals(). But if all the custom fields used in equals() are null, then what would be the best implementation for hashCode()? Example: class Person { private String firstName; private String lastName; public String getFirstName() { return firstName; } public String getLastName() { return lastName; } @Override public boolean equals(Object object) { boolean result = false; if (object == null || object.getClass() != getClass()) { result = false; } else { Person person = (Person) object; if (this.firstName == person.getFirstName() && this.lastName == tiger.getLastName()) { result = true; } } return result; } @Override public int hashCode() { int hash = 3; if(this.firstName == null || this.lastName == null) { // <b>What is the best practice here, </b> // <b>is return super.hashCode() better ?</b> } hash = 7 * hash + this.firstName.hashCode(); hash = 7 * hash + this.lastName.hashCode(); return hash; } } is it required to check for null in hashCode() ? If yes, what should be returned if custom values are null ?

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  • Keyboard navigation for jQuery Tabs

    - by Binyamin
    How to make Keyboard navigation left/up/right/down (like for photo gallery) feature for jQury Tabs with History? Demo without Keyboard feature in http://dl.dropbox.com/u/6594481/tabs/index.html Needed functions: 1. on keyboardtop/down make select and CSS showactivenested ajax tabs from 1-st to last level 2. on keyboardleft/right changeback/forwardcontent ofactivenested ajax tabs tab 3. an extra option, makeactivenested ajax tab on 'cursor-on' on concrete nested ajax tabs level Read more detailed question with example pictures in http://stackoverflow.com/questions/2975003/jquery-tools-to-make-keyboard-and-cookies-feature-for-ajaxed-tabs-with-history /** * @license * jQuery Tools @VERSION Tabs- The basics of UI design. * * NO COPYRIGHTS OR LICENSES. DO WHAT YOU LIKE. * * http://flowplayer.org/tools/tabs/ * * Since: November 2008 * Date: @DATE */ (function($) { // static constructs $.tools = $.tools || {version: '@VERSION'}; $.tools.tabs = { conf: { tabs: 'a', current: 'current', onBeforeClick: null, onClick: null, effect: 'default', initialIndex: 0, event: 'click', rotate: false, // 1.2 history: false }, addEffect: function(name, fn) { effects[name] = fn; } }; var effects = { // simple "toggle" effect 'default': function(i, done) { this.getPanes().hide().eq(i).show(); done.call(); }, /* configuration: - fadeOutSpeed (positive value does "crossfading") - fadeInSpeed */ fade: function(i, done) { var conf = this.getConf(), speed = conf.fadeOutSpeed, panes = this.getPanes(); if (speed) { panes.fadeOut(speed); } else { panes.hide(); } panes.eq(i).fadeIn(conf.fadeInSpeed, done); }, // for basic accordions slide: function(i, done) { this.getPanes().slideUp(200); this.getPanes().eq(i).slideDown(400, done); }, /** * AJAX effect */ ajax: function(i, done) { this.getPanes().eq(0).load(this.getTabs().eq(i).attr("href"), done); } }; var w; /** * Horizontal accordion * * @deprecated will be replaced with a more robust implementation */ $.tools.tabs.addEffect("horizontal", function(i, done) { // store original width of a pane into memory if (!w) { w = this.getPanes().eq(0).width(); } // set current pane's width to zero this.getCurrentPane().animate({width: 0}, function() { $(this).hide(); }); // grow opened pane to it's original width this.getPanes().eq(i).animate({width: w}, function() { $(this).show(); done.call(); }); }); function Tabs(root, paneSelector, conf) { var self = this, trigger = root.add(this), tabs = root.find(conf.tabs), panes = paneSelector.jquery ? paneSelector : root.children(paneSelector), current; // make sure tabs and panes are found if (!tabs.length) { tabs = root.children(); } if (!panes.length) { panes = root.parent().find(paneSelector); } if (!panes.length) { panes = $(paneSelector); } // public methods $.extend(this, { click: function(i, e) { var tab = tabs.eq(i); if (typeof i == 'string' && i.replace("#", "")) { tab = tabs.filter("[href*=" + i.replace("#", "") + "]"); i = Math.max(tabs.index(tab), 0); } if (conf.rotate) { var last = tabs.length -1; if (i < 0) { return self.click(last, e); } if (i > last) { return self.click(0, e); } } if (!tab.length) { if (current >= 0) { return self; } i = conf.initialIndex; tab = tabs.eq(i); } // current tab is being clicked if (i === current) { return self; } // possibility to cancel click action e = e || $.Event(); e.type = "onBeforeClick"; trigger.trigger(e, [i]); if (e.isDefaultPrevented()) { return; } // call the effect effects[conf.effect].call(self, i, function() { // onClick callback e.type = "onClick"; trigger.trigger(e, [i]); }); // default behaviour current = i; tabs.removeClass(conf.current); tab.addClass(conf.current); return self; }, getConf: function() { return conf; }, getTabs: function() { return tabs; }, getPanes: function() { return panes; }, getCurrentPane: function() { return panes.eq(current); }, getCurrentTab: function() { return tabs.eq(current); }, getIndex: function() { return current; }, next: function() { return self.click(current + 1); }, prev: function() { return self.click(current - 1); } }); // callbacks $.each("onBeforeClick,onClick".split(","), function(i, name) { // configuration if ($.isFunction(conf[name])) { $(self).bind(name, conf[name]); } // API self[name] = function(fn) { $(self).bind(name, fn); return self; }; }); if (conf.history && $.fn.history) { $.tools.history.init(tabs); conf.event = 'history'; } // setup click actions for each tab tabs.each(function(i) { $(this).bind(conf.event, function(e) { self.click(i, e); return e.preventDefault(); }); }); // cross tab anchor link panes.find("a[href^=#]").click(function(e) { self.click($(this).attr("href"), e); }); // open initial tab if (location.hash) { self.click(location.hash); } else { if (conf.initialIndex === 0 || conf.initialIndex > 0) { self.click(conf.initialIndex); } } } // jQuery plugin implementation $.fn.tabs = function(paneSelector, conf) { // return existing instance var el = this.data("tabs"); if (el) { return el; } if ($.isFunction(conf)) { conf = {onBeforeClick: conf}; } // setup conf conf = $.extend({}, $.tools.tabs.conf, conf); this.each(function() { el = new Tabs($(this), paneSelector, conf); $(this).data("tabs", el); }); return conf.api ? el: this; }; }) (jQuery); /** * @license * jQuery Tools @VERSION History "Back button for AJAX apps" * * NO COPYRIGHTS OR LICENSES. DO WHAT YOU LIKE. * * http://flowplayer.org/tools/toolbox/history.html * * Since: Mar 2010 * Date: @DATE */ (function($) { var hash, iframe, links, inited; $.tools = $.tools || {version: '@VERSION'}; $.tools.history = { init: function(els) { if (inited) { return; } // IE if ($.browser.msie && $.browser.version < '8') { // create iframe that is constantly checked for hash changes if (!iframe) { iframe = $("<iframe/>").attr("src", "javascript:false;").hide().get(0); $("body").append(iframe); setInterval(function() { var idoc = iframe.contentWindow.document, h = idoc.location.hash; if (hash !== h) { $.event.trigger("hash", h); } }, 100); setIframeLocation(location.hash || '#'); } // other browsers scans for location.hash changes directly without iframe hack } else { setInterval(function() { var h = location.hash; if (h !== hash) { $.event.trigger("hash", h); } }, 100); } links = !links ? els : links.add(els); els.click(function(e) { var href = $(this).attr("href"); if (iframe) { setIframeLocation(href); } // handle non-anchor links if (href.slice(0, 1) != "#") { location.href = "#" + href; return e.preventDefault(); } }); inited = true; } }; function setIframeLocation(h) { if (h) { var doc = iframe.contentWindow.document; doc.open().close(); doc.location.hash = h; } } // global histroy change listener $(window).bind("hash", function(e, h) { if (h) { links.filter(function() { var href = $(this).attr("href"); return href == h || href == h.replace("#", ""); }).trigger("history", [h]); } else { links.eq(0).trigger("history", [h]); } hash = h; window.location.hash = hash; }); // jQuery plugin implementation $.fn.history = function(fn) { $.tools.history.init(this); // return jQuery return this.bind("history", fn); }; })(jQuery); $(function() { $("#list").tabs("#content > div", {effect: 'ajax', history: true}); });

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  • Why is jQuery .load() firing twice?

    - by LeslieOA
    Hello S-O. I'm using jQuery 1.4 with jQuery History and trying to figure out why Firebug/Web Inspector are showing 2 XHR GET requests on each page load (double that amount when visiting my sites homepage (/ or /#). e.g. Visit this (or any) page with Firebug enabled. Here's the edited/relevant code (see full source): - $(document).ready(function() { $('body').delegate('a', 'click', function(e) { var hash = this.href; if (hash.indexOf(window.location.hostname) > 0) { /* Internal */ hash = hash.substr((window.location.protocol+'//'+window.location.host+'/').length); $.historyLoad(hash); return false; } else if (hash.indexOf(window.location.hostname) == -1) { /* External */ window.open(hash); return false; } else { /* Nothing to do */ } }); $.historyInit(function(hash) { $('#loading').remove(); $('#container').append('<span id="loading">Loading...</span>'); $('#ajax').animate({height: 'hide'}, 'fast', 'swing', function() { $('#page').empty(); $('#loading').fadeIn('fast'); if (hash == '') { /* Index */ $('#ajax').load('/ #ajax','', function() { ajaxLoad(); }); } else { $('#ajax').load(hash + ' #ajax', '', function(responseText, textStatus, XMLHttpRequest) { switch (XMLHttpRequest.status) { case 200: ajaxLoad(); break; case 404: $('#ajax').load('/404 #ajax','', ajaxLoad); break; // Default 404 default: alert('We\'re experiencing technical difficulties. Try refreshing.'); break; } }); } }); // $('#ajax') }); // historyInit() function ajaxLoad() { $('#loading').fadeOut('fast', function() { $(this).remove(); $('#ajax').animate({height: 'show', opacity: '1'}, 'fast', 'swing'); }); } }); A few notes that may be helpful: - Using WordPress with default/standard .htaccess I'm redirecting /links-like/this to /#links-like/this via JavaScript only (PE) I'm achieving the above with window.location.replace(addr); and not window.location=addr; Feel free to visit my site if needed. Thanks in advanced.

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  • add a decorate function to a class

    - by wiso
    I have a decorated function (simplified version): class Memoize: def __init__(self, function): self.function = function self.memoized = {} def __call__(self, *args, **kwds): hash = args try: return self.memoized[hash] except KeyError: self.memoized[hash] = self.function(*args) return self.memoized[hash] @Memoize def _DrawPlot(self, options): do something... now I want to add this method to a pre-esisting class. ROOT.TChain.DrawPlot = _DrawPlot when I call this method: chain = TChain() chain.DrawPlot(opts) I got: self.memoized[hash] = self.function(*args) TypeError: _DrawPlot() takes exactly 2 arguments (1 given) why doesn't it propagate self?

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