Re: [sqlite] How does the pager know whether its memory cache is still valid?

Rowan Worth wrote: > How does sqlite determine that the cached page is out of date? http://www.sqlite.org/fileformat2.html#file_change_counter > Ultimately the question I'm trying to answer is whether increasing the size > of the pager cache will reduce the amount of I/O required by a single >

[sqlite] How does the pager know whether its memory cache is still valid?

Hi guys, I haven't been able to figure this one out from the docs, nor have I stumbled onto the right section of the source. Say you have two separate processes accessing an sqlite DB. P1 starts a transaction, reads page #5, ends transaction. P2 starts a transaction, modifies page #5, ends

Re: [sqlite] How does the pager know whether its memory cache is still valid?

On 24 October 2016 at 15:44, Clemens Ladisch wrote: > Rowan Worth wrote: > > How does sqlite determine that the cached page is out of date? > > http://www.sqlite.org/fileformat2.html#file_change_counter > > > Ultimately the question I'm trying to answer is whether increasing

[sqlite] Best way to wipe out data of a closed database

Hi, in an application that implements encryption/decryption with VFS, what is the best way to ensure that the memory of the application doesn't contain decrypted data after the database is closed. So no side application could retrieve sensitive information by reading this process memory. Not only

[sqlite] Warning automatic index on

Hello, In an error log there is a message like: SQlite warning (284) automatic index on is_mytable(internalvalue) What does this mean? Can sqlite not use the index correct? How can we check or optimize the index? What do I have to do to cancel the message? Here is the Table DDL: -- Table:

Re: [sqlite] Warning automatic index on

On 24 October 2016 at 16:59, Werner Kleiner wrote: > Hello, > > In an error log there is a message like: > SQlite warning (284) automatic index on is_mytable(internalvalue) > > What does this mean? > It means that SQLite's query optimiser has decided the most efficient

[sqlite] Bug in latest sqlite Release vacuum crashes?

We have a problem with the latest stable release of SQLite. When compiled for 32 bit under windows and vacuum a database file larger than 2GB, memory storage usage gets up to 2GB and than vacuum crashes with not enough memory. It seems that a temp file is not generated, not for standard and

[sqlite] A small technical question about SQLite

Hi, I am a student in SUNYPOLY, working on my homework. I have a small question. Can someone please contact me? I prefer a phone call at 585-473-6501 Thank you, Liat ___ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org

Re: [sqlite] A small technical question about SQLite

Don't everyone dial at once! On Mon, Oct 24, 2016 at 2:36 PM, LIAT SEAGAL-DERY wrote: > Hi, > > I am a student in SUNYPOLY, working on my homework. I have a small > question. > Can someone please contact me? I prefer a phone call at 585-473-6501 > > Thank you, > Liat

Re: [sqlite] A small technical question about SQLite

Or something. {google} Nothing obvious from a search. It must be safe! On Mon, Oct 24, 2016 at 8:49 PM, Jens Alfke wrote: > I’m guessing it’s probably a phone-sex line. No one would actually expect > strangers to call them to answer their homework problems. > > —Jens > > >

Re: [sqlite] A small technical question about SQLite

I’m guessing it’s probably a phone-sex line. No one would actually expect strangers to call them to answer their homework problems. —Jens > On Oct 24, 2016, at 7:20 PM, Scott Robison wrote: > > Don't everyone dial at once! > > On Mon, Oct 24, 2016 at 2:36 PM, LIAT

Re: [sqlite] Virtual table acting as wrapper of a regular table

Your xFilter method is blindly assuming that there is always an argv[0] without checking argc first. You are incurring an extra "prepare" in your xConnect method, an extra "step" and "column" in your xFilter/xNext methods and an extra "result" in your xColumn function. Doing twice as much work

Re: [sqlite] Virtual table acting as wrapper of a regular table

Indeed I am not checking argc. This code just only means to serve as a test in order to make comparisons for execution speed. I have stripped it of any other functionality. Regarding prepare, I am only preparing the statement in xConnect (which also acts as xCreate). This is only executed

Re: [sqlite] Best way to wipe out data of a closed database

On Mon, Oct 24, 2016 at 1:36 PM, Richard Hipp wrote: > > Memsys5 is also faster than your global system memory allocator > (before the extra overhead of zeroing, at least). But on the other > hand, you have to know the maximum amount of memory SQLite will want > at the very

Re: [sqlite] Best way to wipe out data of a closed database

On 24 Oct 2016, at 9:58am, Max Vlasov wrote: > in an application that implements encryption/decryption with VFS, what > is the best way to ensure that the memory of the application doesn't > contain decrypted data after the database is closed. We can't answer about memory

Re: [sqlite] Best way to wipe out data of a closed database

On 10/24/16, Max Vlasov wrote: > > One of the trick possible is to add additional zeroing out to the > global free handler, but this can probably introduce performance > penalties. > > Is there any other way to do this? If you set up to use memsys5 at compile-time

Re: [sqlite] Best way to wipe out data of a closed database

Simon, thanks never heard of secure_delete, interesting, but probably no use in case of VFS Layer that leaves only encrypted data on disk. As for zero-malloc option, it looks promising. On Mon, Oct 24, 2016 at 1:34 PM, Simon Slavin wrote: > > On 24 Oct 2016, at 9:58am, Max

Re: [sqlite] Warning automatic index on

I have dropped the double index DROP INDEX 'InternalName'; Then executed the SQL Select statement which caused the sqlite warning. But same warning, nothing changed. Then I added a new index CREATE INDEX idx_installid ON ... Now the sqlite warning is gone away. :-) The SQL statement has a JOIN

Re: [sqlite] Warning automatic index on

Please post the result of the following query: SELECT sqlite_source_id(); On 10/24/16, Werner Kleiner wrote: > I have dropped the double index > DROP INDEX 'InternalName'; > Then executed the SQL Select statement which caused the sqlite warning. > But same warning,

Re: [sqlite] Import 5000 xml files in a sqlite database file

Scripting powershell? C#? El 23/10/2016 18:04, "Sylvain Pointeau" escribió: > hello, > > I am not sure if Oxygen or another XML specialized software could do it, > however it would be easy done using C or C++ or Java. Advantage is that it > is then easy to automatize

Re: [sqlite] Best way to wipe out data of a closed database

It sounds like you've got a way forward on leaks via the malloc() system within the process space. Be aware that depending on your system (and the attackers' capabilities), you might have to worry about other leaks. For instance, if I did a query that involved a FLOAT index, and then closed

Re: [sqlite] Virtual table acting as wrapper of a regular table

When you prepare() your statement, SQLite translates this into 2 nested loops: Outer loop: Rewind table A (retrieve first row) Extract id from table A row ... Retrieve next row from table A Inner loop: Set table B to A.id Extract id from B Check for match (return

Re: [sqlite] Best way to wipe out data of a closed database

On Mon, Oct 24, 2016 at 4:28 PM, Wade, William wrote: > It sounds like you've got a way forward on leaks via the malloc() system > within the process space. > > 1) The region of the C process stack that was reached by some deep call stack. > 2) Processor registers. > 3)

Re: [sqlite] How does the pager know whether its memory cache is still valid?

On 10/25/2016 01:12 AM, Jens Alfke wrote: On Oct 24, 2016, at 1:31 AM, Rowan Worth wrote: OK, so the entire cache is invalidated when another process updates the DB, which is what I feared. In this case I'm looking at too many concurrent updates for caching to add much value.

[sqlite] Does Reindex Change Stats Tables?

> REINDEX does *not* update the stats. You must run ANALYZE separately. > May I ask why you are running REINDEX? Sure. We issue new releases of our application about every 3 months. With some of these, we update the schema of the underlying DB. And with some of these schema updates, we have

Re: [sqlite] Warning automatic index on

On 10/24/16, Simon Slavin wrote: > > I think it's the "DESC". Since SQLite understands how to search an index > backwards when it needs to, try dropping the DESC on that index and see if > the problem goes away. He already has another index without the DESC :-\ I think

Re: [sqlite] Warning automatic index on

The result is: 2015-05-04 19:13:25 850c11866686a7b39d7b163fb60898c11283688e 2016-10-24 14:28 GMT+02:00 Richard Hipp : > Please post the result of the following query: > > SELECT sqlite_source_id(); > > On 10/24/16, Werner Kleiner wrote: >> I have

Re: [sqlite] Warning automatic index on

On 10/24/16, Werner Kleiner wrote: > > In an error log there is a message like: > SQlite warning (284) automatic index on is_mytable(internalvalue) > I do not know why SQLite is warning you about a lack of an index on internalvalue when it is really missing an index on

Re: [sqlite] How does the pager know whether its memory cache is still valid?

> On Oct 24, 2016, at 1:31 AM, Rowan Worth wrote: > > OK, so the entire cache is invalidated when another process updates the DB, > which is what I feared. In this case I'm looking at too many concurrent > updates for caching to add much value. I’m no expert on the internals,

[sqlite] Does Reindex Change Stats Tables?

I am wondering if I run reindex than should I always run analyze afterward? If the reindex command though also updates the stats in addition to recreating the actual indexes, then of course i would not need it. Thanks, Denis ___ sqlite-users mailing

Re: [sqlite] Does Reindex Change Stats Tables?

On 10/24/16, Denis Burke wrote: > I am wondering if I run reindex than should I always run analyze > afterward? If the reindex command though also updates the stats in > addition to recreating the actual indexes, then of course i would not need > it. > REINDEX does *not*

Re: [sqlite] Development environment reccomendation

On 24 Oct 2016, at 6:26am, Philip Rhoades wrote: > What development environment would people suggest for building the sqlite app? If I understand correctly, 'mmssms.db' is itself a SQLite database file. So your choice comes down to whatever programming

Re: [sqlite] Virtual table acting as wrapper of a regular table

Hick, sorry, I think I misunderstood your first reply. Yes, of course I am calling each method twice when I use the wrapper: one time in the wrapper and one time in B, so an overhead is absolutely expected. But I would not expect this overhead to be equal to the time of the total execution

Re: [sqlite] Warning automatic index on

On 24 Oct 2016, at 10:11am, Rowan Worth wrote: > However I see you already have an index 'InternalName' which covers the > 'internalvalue' column, so not sure why that isn't being used. Maybe it's > confused by the DESC or the MySQL back-ticks? I think it's the "DESC". Since

Re: [sqlite] Import 5000 xml files in a sqlite database file

Bob, my name is Kevin Youren, and I did this task about 4 years ago in Python 3, by parsing XML files and creating CSV files. The CSV files were used to load Sqlite tables, MS Xcel spreadsheets and IBM mainframe DB2 tables. The XML data was mildly complex, large, and error prone. If you have a

Re: [sqlite] Does Reindex Change Stats Tables?

On 10/24/16, Denis Burke wrote: >> REINDEX does *not* update the stats. You must run ANALYZE separately. > >> May I ask why you are running REINDEX? > > Sure. We issue new releases of our application about every 3 months. With > some of these, we update the schema of the

Re: [sqlite] spellfix1 is unable to match words beginning with 'Kn' and 'Gn'

On 10/20/16, Thomas David Baker wrote: > Is this the right list to report issues with the spellfix1 extension? > > Here's a complete repro case: lowercase your vocabulary and it should work fine. The special case logic for unusual letter combinations like "kn" and "gn" only