Re: [sqlite] p in sclp in parse.y
Hello Himanshu,
I'll look into it today, and get back.
Thanks
Uma
HG <[EMAIL PROTECTED]> wrote: Hello,
Could you tell me what the 'p' in 'sclp' in 'parse.y' stands for? I am
trying to make a modification to the grammar file.
Also the rule for sclp uses selcollist and the rule for selcollist
uses sclp in some kind of mutual recursion. Is this a lemon feature or
normal with LALR grammars.
Thank You,
HG
[snipped parse.y beginning]
%type sclp {ExprList*}
%destructor sclp {sqlite3ExprListDelete($$);}
sclp(A) ::= selcollist(X) COMMA. {A = X;}
sclp(A) ::= .{A = 0;}
selcollist(A) ::= sclp(P) expr(X) as(Y). {
A = sqlite3ExprListAppend(pParse,P,X,Y.n?:0);
}
selcollist(A) ::= sclp(P) STAR. {
Expr *p = sqlite3PExpr(pParse, TK_ALL, 0, 0, 0);
A = sqlite3ExprListAppend(pParse, P, p, 0);
}
selcollist(A) ::= sclp(P) nm(X) DOT STAR. {
Expr *pRight = sqlite3PExpr(pParse, TK_ALL, 0, 0, 0);
Expr *pLeft = sqlite3PExpr(pParse, TK_ID, 0, 0, );
Expr *pDot = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight, 0);
A = sqlite3ExprListAppend(pParse,P, pDot, 0);
}
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Re: [sqlite] Re: Threads
No I'm not currently parallel I/O. But I was hoping to use multiple Sqlite databases (in-memory, disk based etc), and wanted to know the recommended policy in that case. At present, since SQLite is a single file, there can be no parallel I/O within a single DB - right? John Stanton <[EMAIL PROTECTED]> wrote: Do you have parallel I/O or are you using Windows or Unix? Uma Krishnan wrote: > How about when you need to take advantage of parallel I/O etc, or you need to > access multiple SQLite databases w/i a transaction? > > Are you dissuading thread usage from DB application point of view, or even > within SQLite kernel? > > Thanks in advance > > - Uma > > > John Stanton wrote: One of the ignored points about thread usage is just how > expensive are > the synchronization mechanisms. It is a good idea to apply Occam's > Razor to your design and eliminate unnecessary features and have a > result which provides a better level of functionality and a structure > which is much simpler to prove correct. > > I see situations where there is a complex web of worker threads etc > applied to what would otherwise be a simple problem. The result runs > slowly and has hidden race conditions and other defects. DRH's > reservations about threads come to mind. > > Applications run best when they can be reduced to a single stream > without any synchronization requirements. > > Threads are indispensible when multiplexing a user interface but are > very dispensible when handling a single resource like a database. > > Joe Wilson wrote: > >>--- Ken wrote: >> >> >>>In general I'v found that Thread cancellation is very painful, >>>a simpler paradigm to utilize is the lock timeout with a Global >>>variable status check. >> >> >>Rather than check a global variable you could simply pass a null >>event to the queue which instructs the thread to simply to finish >>(a.k.a. return) gracefully. That way you can avoid the lock timeout >>and polling. >> >>On the GUI thread, however a timeout and poll may be necessary >>depending on the framework. >> >> >> >> >>Be a better pen pal. >>Text or chat with friends inside Yahoo! Mail. See how. >>http://overview.mail.yahoo.com/ >> >>- >>To unsubscribe, send email to [EMAIL PROTECTED] >>- >> > > > > - > To unsubscribe, send email to [EMAIL PROTECTED] > - > > > - To unsubscribe, send email to [EMAIL PROTECTED] -
Re: [sqlite] Re: Threads
How about when you need to take advantage of parallel I/O etc, or you need to access multiple SQLite databases w/i a transaction? Are you dissuading thread usage from DB application point of view, or even within SQLite kernel? Thanks in advance - Uma John Stanton <[EMAIL PROTECTED]> wrote: One of the ignored points about thread usage is just how expensive are the synchronization mechanisms. It is a good idea to apply Occam's Razor to your design and eliminate unnecessary features and have a result which provides a better level of functionality and a structure which is much simpler to prove correct. I see situations where there is a complex web of worker threads etc applied to what would otherwise be a simple problem. The result runs slowly and has hidden race conditions and other defects. DRH's reservations about threads come to mind. Applications run best when they can be reduced to a single stream without any synchronization requirements. Threads are indispensible when multiplexing a user interface but are very dispensible when handling a single resource like a database. Joe Wilson wrote: > --- Ken wrote: > >>In general I'v found that Thread cancellation is very painful, >>a simpler paradigm to utilize is the lock timeout with a Global >>variable status check. > > > Rather than check a global variable you could simply pass a null > event to the queue which instructs the thread to simply to finish > (a.k.a. return) gracefully. That way you can avoid the lock timeout > and polling. > > On the GUI thread, however a timeout and poll may be necessary > depending on the framework. > > > > > Be a better pen pal. > Text or chat with friends inside Yahoo! Mail. See how. > http://overview.mail.yahoo.com/ > > - > To unsubscribe, send email to [EMAIL PROTECTED] > - > - To unsubscribe, send email to [EMAIL PROTECTED] -
Re: [sqlite] SQLITE3 Prepare / Step
Got it. Thanks a million - Uma John Stanton <[EMAIL PROTECTED]> wrote: The prepare creates a virtual machine which can be rused. A useful way to implement Sqlite is to use prepare to compile all the SQL in the initialization phase of the program and then to execute the virutal machines using step. By compiling a SQL in advance you can ensure that the program will not fail in mid execution with an SQl error. Uma Krishnan wrote: > In SQLite3 one uses prepare/step to execute query. The question that I have > is, when your stepping yields no more rows, and one has to re-execute the > query, does one have to call the prepare statement again. If that's the case, > what's the advantage of pre-compiling. If not, how does Sqlite3 knows it has > to reissue the query. > > In standard DB/JDBC parlance, one prepares (one time, unless recompiled), > executes, loops for next (/step) until all rows fetched, then closes. > Subsequently one can skip prepare and proceed to execute. > > Thanks in advance > > Uma > > > > > Uma Krishnan wrote: Yes. Makes sense (not to cache query results for > embedded apps). So what is cached. Just dirty pages? or are raw tables cached > when queried? > > Thanks > > Uma > > Scott Hess wrote: On 10/17/07, Trevor Talbot wrote: > >>On 10/17/07, Uma Krishnan wrote: >> >>>One other question, when a query is issued, does SQLite cache the results, >>>so that future queries can be processed off the cache (I think not) >> >>Like the "query cache" in some other databases? No. >> >>SQLite does have a cache of database pages, but they mimic what's on >>disk, not the results of a particular query. >> >>A query cache would not be very useful for an embedded database. If >>you're caching results, you might as well do it in the application's >>native form -- it's the same process after all. > > > To add another nail, the reason a query cache is often useful in > database servers is because you can usually share the cache across all > the front-ends. Since SQLite effectively lives inside the front-end, > this sharing goes away. Worse, any caching SQLite does is adding to > the memory footprint of the containing app (or, put another way, > stealing memory the app could use in other ways). > > -scott > > - To unsubscribe, send email to [EMAIL PROTECTED] -
[sqlite] SQLITE3 Prepare / Step
In SQLite3 one uses prepare/step to execute query. The question that I have is, when your stepping yields no more rows, and one has to re-execute the query, does one have to call the prepare statement again. If that's the case, what's the advantage of pre-compiling. If not, how does Sqlite3 knows it has to reissue the query. In standard DB/JDBC parlance, one prepares (one time, unless recompiled), executes, loops for next (/step) until all rows fetched, then closes. Subsequently one can skip prepare and proceed to execute. Thanks in advance Uma Uma Krishnan <[EMAIL PROTECTED]> wrote: Yes. Makes sense (not to cache query results for embedded apps). So what is cached. Just dirty pages? or are raw tables cached when queried? Thanks Uma Scott Hess wrote: On 10/17/07, Trevor Talbot wrote: > On 10/17/07, Uma Krishnan wrote: > > One other question, when a query is issued, does SQLite cache the results, > > so that future queries can be processed off the cache (I think not) > > Like the "query cache" in some other databases? No. > > SQLite does have a cache of database pages, but they mimic what's on > disk, not the results of a particular query. > > A query cache would not be very useful for an embedded database. If > you're caching results, you might as well do it in the application's > native form -- it's the same process after all. To add another nail, the reason a query cache is often useful in database servers is because you can usually share the cache across all the front-ends. Since SQLite effectively lives inside the front-end, this sharing goes away. Worse, any caching SQLite does is adding to the memory footprint of the containing app (or, put another way, stealing memory the app could use in other ways). -scott - To unsubscribe, send email to [EMAIL PROTECTED] -
Re: [sqlite] HELP WITH SQLITE INTERNALS - VDBE and Virtual tables
Yes. Makes sense (not to cache query results for embedded apps). So what is cached. Just dirty pages? or are raw tables cached when queried? Thanks Uma Scott Hess <[EMAIL PROTECTED]> wrote: On 10/17/07, Trevor Talbot wrote: > On 10/17/07, Uma Krishnan wrote: > > One other question, when a query is issued, does SQLite cache the results, > > so that future queries can be processed off the cache (I think not) > > Like the "query cache" in some other databases? No. > > SQLite does have a cache of database pages, but they mimic what's on > disk, not the results of a particular query. > > A query cache would not be very useful for an embedded database. If > you're caching results, you might as well do it in the application's > native form -- it's the same process after all. To add another nail, the reason a query cache is often useful in database servers is because you can usually share the cache across all the front-ends. Since SQLite effectively lives inside the front-end, this sharing goes away. Worse, any caching SQLite does is adding to the memory footprint of the containing app (or, put another way, stealing memory the app could use in other ways). -scott - To unsubscribe, send email to [EMAIL PROTECTED] -
Re: [sqlite] HELP WITH SQLITE INTERNALS - VDBE and Virtual tables
Thanks John and Joe for your responses. As far as I know, Postgres does not have a virtual engine. I could be wrong. One other question, when a query is issued, does SQLite cache the results, so that future queries can be processed off the cache (I think not) Thanks Uma John Stanton <[EMAIL PROTECTED]> wrote: >Moreover, is it typical to have an implementation like VDBE in other databases as well? This is a common approach and has been used for a very long time. For example we used it in products produced during the 1980s because producing a virtual machine and a compiler for its application-specific instruction set was a far better solution than masses of procedural logic. At that time it was a time honored technique and not at all innovative. Look at how PostgreSQL compiles and stores SQL statements for background information on the concept. - To unsubscribe, send email to [EMAIL PROTECTED] -
[sqlite] HELP WITH SQLITE INTERNALS - VDBE and Virtual tables
Hello, I'm a student trying to understand SQLite for my DB project. There are a couple of aspects that I don't quite understand: 1) VDBE. I see how the vdbe stack is created using VDBEAddOp etc. But once the code is generated, I don't see when it's executed. Moreover, is it typical to have an implementation like VDBE in other databases as well? 2) VIRTUAL TABLES. Why should the shared_cache be disabled when using VIRTUAL TABLES? Thanks Uma
[sqlite] sqlite3_prepare vs. sqlite3_get_table
Hello, Is sqlite3_get_table a legitimate call when you want to get a bunch of rows? what are the pros and cons as against using sqlite3_prepare/step. Thanks in advance. Uma
[sqlite] HELP!!!! LINKING AND LOADING FTS - on Linux/Ubuntu
Hello,
I'm having trouble loading fts2. I modified makefile to create fts2
library on Linux/Ubuntu.
When I attempt to load fts2 using the command:
select load_extension('fts2'), i get the error shared library not found.
( noticed that it had not created the .so file, only .la file.)
I do have the LD_LIBRARY set up correctly.
What am I doing wrong?
Thanks in advance
Uma
Uma Krishnan <[EMAIL PROTECTED]> wrote: Hello,
I'm having trouble loading fts2. I modified makefile to create fts2 library on
Linux/Ubuntu.I
When I attempt to load fts2 using the command select load_extension('fts2'), i
get the error shared library not found.
( noticed that it had not created the .so file, only .la file.)
What am I doing wrong?
Thanks in advance
Uma
Igor Tandetnik wrote: Kefah T. Issa wrote:
>> I tried the ordered-urls-insert the results were better, but it is
>> still
>> taking progressively longer time as the number of records increases.
>>
>> A fundamental question to be asked here :
>>
>> Shouldn't the time complexity (Big-O) of the insert operation be
>> constant?
Of course not. It takes O(log N) to find an appropriate place in the
index for every new record (where N is the number of records already
inserted). Also, it generates a lot of disk activity once the index
grows too large to fit in memory cache.
>> I even did a third test where the integer primary key is not auto
>> increment;
>> the same problem is observed.
The id is not a problem: O(log N) is caused by the index on url.
Igor Tandetnik
-
To unsubscribe, send email to [EMAIL PROTECTED]
-
[sqlite] LINKING AND LOADING FTS - on Linux/Ubuntu
Hello,
I'm having trouble loading fts2. I modified makefile to create fts2 library on
Linux/Ubuntu.I
When I attempt to load fts2 using the command select load_extension('fts2'), i
get the error shared library not found.
( noticed that it had not created the .so file, only .la file.)
What am I doing wrong?
Thanks in advance
Uma
Igor Tandetnik <[EMAIL PROTECTED]> wrote: Kefah T. Issa wrote:
>> I tried the ordered-urls-insert the results were better, but it is
>> still
>> taking progressively longer time as the number of records increases.
>>
>> A fundamental question to be asked here :
>>
>> Shouldn't the time complexity (Big-O) of the insert operation be
>> constant?
Of course not. It takes O(log N) to find an appropriate place in the
index for every new record (where N is the number of records already
inserted). Also, it generates a lot of disk activity once the index
grows too large to fit in memory cache.
>> I even did a third test where the integer primary key is not auto
>> increment;
>> the same problem is observed.
The id is not a problem: O(log N) is caused by the index on url.
Igor Tandetnik
-
To unsubscribe, send email to [EMAIL PROTECTED]
-
Re: [sqlite] HELP - CREATING A SQLITE3 BINARY INSTEAD OF A BASH
Thanks Joe and Dan Yes, I now have the binary file. Much appreciated - Uma Joe Wilson <[EMAIL PROTECTED]> wrote: autoconf generates the sqlite3 script when libsqlite3.so is used to set up the LD_LIBRARY_PATH. To avoid this, build a static sqlite3. ./configure --disable-shared make clean make sqlite3 optional: file sqlite3 ldd sqlite3 --- Uma Krishnan wrote: > I'm trying to debug sqlite3. But in order for me to do that, I need sqlite3 > binary. The makefile > generates a bash file. I'm confused as how that happens. After all, gcc is > used to generate > sqlite3 executable Take the Internet to Go: Yahoo!Go puts the Internet in your pocket: mail, news, photos & more. http://mobile.yahoo.com/go?refer=1GNXIC - To unsubscribe, send email to [EMAIL PROTECTED] -
[sqlite] HELP - CREATING A SQLITE3 BINARY INSTEAD OF A BASH
Hello, I'm trying to debug sqlite3. But in order for me to do that, I need sqlite3 binary. The makefile generates a bash file. I'm confused as how that happens. After all, gcc is used to generate sqlite3 executable Any pointers will be much appreciated. Thanks Uma
Re: [sqlite] HELP! DDD & SQLite
Hello Ken, I just realized that sqlite3 is a bash program. When I do ddd sqlite3, it gives an error. So when I need to load a program, thru GUI interface I load main.o. But I guess that's not right What should I do? Thanks Uma Ken <[EMAIL PROTECTED]> wrote: you need to set a breakpoint. hit the continue button in DDD. That will allow execution of the code and allow the attached program to continue. It would be better however to run ddd as follows: ddd sqlite3 Then set a breakpoint. Then run the program inside the ddd that way you can first set breakpoints prior to execution. Ken Uma Krishnan wrote: Hello I'm trying to debug SQLite (to understand the code). But e when I attach the process sqlite3, the sqlite3 terminal hangs (ie would not accept any user inputs) till I detach. Can someone please tell me what I'm doing wrong Thanks Uma Cory Nelson wrote: On 9/7/07, Yves Goergen wrote: > Hi, > > in a scenario when multiple operations need to be transactionally > synchronised, I have a file that must be deleted when the database > records are added successfully, but the database operations must be > rolled back, if the file cannot be deleted. > > I'm currently using a transaction for this on the database side and > rolling it back if the file cannot be deleted. But what if the file is > gone and then SQLite says it doesn't accept my records? Since we're > inside a transaction, integrity checks should be deferred until a > COMMIT. Is there a way to tell whether the COMMIT will succeed under the > current conditions so that I can safely delete the file? My understanding is that if your first insert succeeds you hold a write lock on the table and barring any exceptional errors a commit should always succeed. -- Cory Nelson - To unsubscribe, send email to [EMAIL PROTECTED] -
[sqlite] HELP! DDD & SQLite
Hello I'm trying to debug SQLite (to understand the code). But e when I attach the process sqlite3, the sqlite3 terminal hangs (ie would not accept any user inputs) till I detach. Can someone please tell me what I'm doing wrong Thanks Uma Cory Nelson <[EMAIL PROTECTED]> wrote: On 9/7/07, Yves Goergen wrote: > Hi, > > in a scenario when multiple operations need to be transactionally > synchronised, I have a file that must be deleted when the database > records are added successfully, but the database operations must be > rolled back, if the file cannot be deleted. > > I'm currently using a transaction for this on the database side and > rolling it back if the file cannot be deleted. But what if the file is > gone and then SQLite says it doesn't accept my records? Since we're > inside a transaction, integrity checks should be deferred until a > COMMIT. Is there a way to tell whether the COMMIT will succeed under the > current conditions so that I can safely delete the file? My understanding is that if your first insert succeeds you hold a write lock on the table and barring any exceptional errors a commit should always succeed. -- Cory Nelson - To unsubscribe, send email to [EMAIL PROTECTED] -
Re: [sqlite] FTS2 suggestion
Hello Scott, I have several clarifications with respect to full text search. I'm a newbie in open source development, so please bear with me if some of the questions are irrelevant/obvious/nonsense. I was given to understand that the potter stemming algorithm implemented in fts2 is not robust enough (or rather snowball is more accurate). If fts2(or 3) has to be made more robust, then what should be the next step. The following url (I thought) gave the steps to follow rather succinctly: http://web.njit.edu/~wu/teaching/CIS634/GoodProjects/AccessLisa/documentation.php At what stage would n-gram kick in (I assume n-gram would be in conjunction to snowball/potter). Which would be a good n-gram algorithm to implement. Finally, what's the rationale in having sqlite's own search. Why not use something like luceneC? Thanks in advance Uma Scott Hess <[EMAIL PROTECTED]> wrote: Porter stemmer is already in there. The main issue with Porter is that it's English only. There is no general game-plan for fuzzy search at this time, though if someone wants to step into the breech, go for it! Even a prototype which demonstrates the concepts and problems but isn't production-ready would be worth something. My current focus for the next generation is international support (this is more of a Google Gears project, but with focus on SQLite so there is likely to be stuff checked in on the SQLite side), and more scalable/manageable indexing. Not a lot of focus on things like quality and recall, mostly because I'm not aware of any major users with enough of an installed baseline to even generate decent metrics. [Basically, solving concrete identified problems rather than looking for ill-defined potential problems.] -scott On 8/24/07, Uma Krishnan wrote: > Would it not be more useful to first implement potter stemmer algorithm, and > then to implement n-gram (as I understand n-gram is for cross column fuzzy > search?). What is the general game plan for FTS3 with regard to fuzzy search? > > Thanks in advance > > "Cesar D. Rodas" wrote: > On 23/08/07, Scott Hess wrote: > > On 8/20/07, Cesar D. Rodas wrote: > > > As I know ( I can be wrong ) SQLite Full Text Search is only match with > > > hole > > > words right? It could not be > > > And also no FT extension to db ( as far I know) is miss spell tolerant, > > > > Yes, fts is matching exactly. There is some primitive support for > > English stemming using the Porter stemmer, but, honestly, it's not > > well-exercised. > > > > > And > > > I've found this Paper that talks about *Using Superimposed Coding Of > > > N-Gram > > > Lists For Efficient Inexact Matching* > > > > http://citeseer.ist.psu.edu/cache/papers/cs/22812/http:zSzzSzwww.novodynamics.comzSztrenklezSzpaperszSzatc92v.pdf/william92using.pdf > > > > > > I was reading and it is not so hard to implement, but it cost a extra > > > storage space, but I think the benefits are more. > > > > > > Also following this paper could be done a way to match with fragments of > > > words... what do you think of it? > > > > It's an interesting paper, and I must say that anything which involves > > Bloom Filters automatically draws my attention :-). > > Yeah. I am doing some investigations about that, I love that too. And > I was watching that with n-grams you get a filter to stop common > words, and could be used as a stemming-like algorithm but independent > from the language. > > I was thinking to implement this > http://www.mail-archive.com/sqlite-users%40sqlite.org/msg26923.html > when I finish up some things. What do you think of it? > > > While I think spelling-suggestion might be valuable for fts in the > > longer term, I'm not very enthusiastic about this particular model. > > It seems much more useful in the standard indexing model of building > > the index, manually tweaking it, and then doing a ton of queries > > against it. fts is really fairly constrained, because many use-cases > > are more along the lines of update the index quite a bit, and query it > > only a few times. > > > > Also, I think the concepts in the paper might have very significant > > problems handling Unicode, because the bit vectors will get so very > > large. I may be wrong, sometimes the overlapping-vector approach can > > have surprising relevance depending on the frequency distribution of > > the things in the vector. It would need some experimentation to > > figure that out. > > > > Certainly something to bookmark, though. > > > > Thanks, > > scott > > > > - > >
Re: [sqlite] sqlite db portability
Just FYI, ODBC specs is very similar to JDBC, except that ODBC is in C whereas JDBC is in java. Thanks Uma Markus Hoenicka <[EMAIL PROTECTED]> wrote: Quoting Uma Krishnan : > Hello Markus, > > How is libdbi different from, say odbc? > I've never used ODBC, but from what I read I'd say the main differences are the footprint and the scope. libdbi is language-specific (C), lightweight, and allows you to do simple things in a simple fashion. However, you're still required to handle database engine specific stuff in your code to use more advanced SQL features. ODBC seems to encapsulate all and everything, at the price of being huge. regards, Markus -- Markus Hoenicka [EMAIL PROTECTED] (Spam-protected email: replace the quadrupeds with "mhoenicka") http://www.mhoenicka.de - To unsubscribe, send email to [EMAIL PROTECTED] -
Re: [sqlite] sqlite db portability
Hello Markus, How is libdbi different from, say odbc? Thanks in advance Uma Markus Hoenicka <[EMAIL PROTECTED]> wrote: Shilpa Sheoran writes: > Can the sqlite db file be accessed using another DB api's eg. MySQL > or anyother. > Not directly, but you can use a database abstraction layer like libdbi (http://libdbi.sourceforge.net) for C or the DBI/DBD stuff for Perl. Your program uses the abstraction layer's API instead of the database-specific API. regards, Markus -- Markus Hoenicka [EMAIL PROTECTED] (Spam-protected email: replace the quadrupeds with "mhoenicka") http://www.mhoenicka.de - To unsubscribe, send email to [EMAIL PROTECTED] -
Re: [sqlite] FTS2 suggestion
Would it not be more useful to first implement potter stemmer algorithm, and then to implement n-gram (as I understand n-gram is for cross column fuzzy search?). What is the general game plan for FTS3 with regard to fuzzy search? Thanks in advance "Cesar D. Rodas" <[EMAIL PROTECTED]> wrote: On 23/08/07, Scott Hess wrote: > On 8/20/07, Cesar D. Rodas wrote: > > As I know ( I can be wrong ) SQLite Full Text Search is only match with hole > > words right? It could not be > > And also no FT extension to db ( as far I know) is miss spell tolerant, > > Yes, fts is matching exactly. There is some primitive support for > English stemming using the Porter stemmer, but, honestly, it's not > well-exercised. > > > And > > I've found this Paper that talks about *Using Superimposed Coding Of N-Gram > > Lists For Efficient Inexact Matching* > > http://citeseer.ist.psu.edu/cache/papers/cs/22812/http:zSzzSzwww.novodynamics.comzSztrenklezSzpaperszSzatc92v.pdf/william92using.pdf > > > > I was reading and it is not so hard to implement, but it cost a extra > > storage space, but I think the benefits are more. > > > > Also following this paper could be done a way to match with fragments of > > words... what do you think of it? > > It's an interesting paper, and I must say that anything which involves > Bloom Filters automatically draws my attention :-). Yeah. I am doing some investigations about that, I love that too. And I was watching that with n-grams you get a filter to stop common words, and could be used as a stemming-like algorithm but independent from the language. I was thinking to implement this http://www.mail-archive.com/sqlite-users%40sqlite.org/msg26923.html when I finish up some things. What do you think of it? > While I think spelling-suggestion might be valuable for fts in the > longer term, I'm not very enthusiastic about this particular model. > It seems much more useful in the standard indexing model of building > the index, manually tweaking it, and then doing a ton of queries > against it. fts is really fairly constrained, because many use-cases > are more along the lines of update the index quite a bit, and query it > only a few times. > > Also, I think the concepts in the paper might have very significant > problems handling Unicode, because the bit vectors will get so very > large. I may be wrong, sometimes the overlapping-vector approach can > have surprising relevance depending on the frequency distribution of > the things in the vector. It would need some experimentation to > figure that out. > > Certainly something to bookmark, though. > > Thanks, > scott > > - > To unsubscribe, send email to [EMAIL PROTECTED] > - > > -- Cesar D. Rodas http://www.cesarodas.com/ Mobile Phone: 595 961 974165 Phone: 595 21 645590 [EMAIL PROTECTED] [EMAIL PROTECTED] - To unsubscribe, send email to [EMAIL PROTECTED] -
RE: [sqlite] In-Memory
Great! Thanks a lot
- Uma
[EMAIL PROTECTED] wrote:
from sqlite3 import dbapi2 as sqlite
connection = sqlite.connect(':memory:')
cursor.execute(' . . . sql statements . . .')
cursor.close()
Whatever sql operations you do will be in memory. Once you exit the
applcation, DB will be lost
Uma Krishnan
08/08/07 10:44 PM
Please respond to
sqlite-users@sqlite.org
To
sqlite-users@sqlite.org
cc
Subject
RE: [sqlite] In-Memory
Hello,
Has anyone used SQLite as an In-Memory implementation. If so would you
like to share your ideas?
Thanks in advance
- Uma
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RE: [sqlite] In-Memory
Hello, Has anyone used SQLite as an In-Memory implementation. If so would you like to share your ideas? Thanks in advance - Uma
Re: [sqlite] sqlite3
How about the various implementations to use SQLite in client server environment (based on wiki): http://www.it77.de/sqlite/sqlite.htm http://www.oneledger.co.uk/sql4sockets.html http://users.iol.it/irwin/ http://sqlitedbms.sourceforge.net/ Does anyone have any experience any of these? Pros and cons? Thanks Uma [EMAIL PROTECTED] wrote: Huber Privat wrote: > Guten Tag > > Ich arbeite mit SQLite3 über ein Netzwerk. > > Wenn 2 User zur gleichen Zeit arbeiten wird der > Zugriff auf die SQLite3-Datenbank sehr langsam. > > Was mache ich falsch. > Bitte um Hilfe. > SQLite tends to not work well on a network filesystem. This is because network filesystems are themselves slow. This is especially true when you have multiple processes attempting to access the database at the same time. A lot of traffic has to go back and forth across the network in order to negotiate the approriate locks. If you have multiple clients access a single database over a network, you are probably better off using a client/server database engine. -- D. Richard Hipp - To unsubscribe, send email to [EMAIL PROTECTED] -
[sqlite] FTS2
Downloading SQLite source does not come with FTS2 source? If not, how do I download FTS2 source. I see only a way to download binary. Thanks in advance Uma
[sqlite] Lemon Parser: Modular
I had posted earlier to find if Lemon parser can be made modular. As per previous post responses, who had advised that I look in lemon parser forum. But I could not find a separate forum. Please refer to the following link to get a better idea of what I'm trying to do: http://www.patentstorm.us/patents/7089541-claims.html Thanks Uma
Re: [sqlite] Lemon Parser - Modular & Extensible ?
Hey, There's no need to be offensive. I did not mean to be critical. Far from it, it does a great a job (far more than I'm capable of producing). What I was trying to find out was, if it is possible for a .y files to be broken such that it can be built on top on other .y files. Not sure if this is the right group. But could not find a lemon parser user group. Christian Smith <[EMAIL PROTECTED]> wrote: Uma Krishnan uttered: > Hello: > > Is lemon parser modular and extensible? Extensible to do what? It generates parsers, and is self contained. It does a single job, and does it well. What more could you ask for? > > Thanks > > Uma > > Asif Lodhi wrote: > Hi Everybody, > > I have just joined this mailing list as Sqlite looks like a good > software solution to my needs. What I need right now is RE-assurance > of "crash-recovery" that is mentioned on your front page. So, I would > be thankful if you experts would give me an "accurate" and fair > picture of the crash-recovery aspects of SQLite - without any hype. > > -- > Best regards, > > Asif > > - > To unsubscribe, send email to [EMAIL PROTECTED] > - > > > -- /"\ \ / ASCII RIBBON CAMPAIGN - AGAINST HTML MAIL X - AGAINST MS ATTACHMENTS / \ - To unsubscribe, send email to [EMAIL PROTECTED] -
[sqlite] Lemon Parser - Modular & Extensible ?
Hello: Is lemon parser modular and extensible? Thanks Uma Asif Lodhi <[EMAIL PROTECTED]> wrote: Hi Everybody, I have just joined this mailing list as Sqlite looks like a good software solution to my needs. What I need right now is RE-assurance of "crash-recovery" that is mentioned on your front page. So, I would be thankful if you experts would give me an "accurate" and fair picture of the crash-recovery aspects of SQLite - without any hype. -- Best regards, Asif - To unsubscribe, send email to [EMAIL PROTECTED] -
