Hello, I'm having a problem with libzdb. I have a connection pool to sqlite and I get a connection to perform a select query. Now, while processing the result set I want to update certain tables from the database. The problem is:
If I get a new connection from the pool I get a "database file is locked" so I'm gessing that a connection locks the database file while it's active. The other solution may be to use the same conection to execute the update, but that messes the result set to when it tries to get next element I get a Segmentation Fault.
Is there a way to open a "Read only" connection so it doesn't lock the entire database? If not, is there a way to make a copy of a result set to execute another query?
This is a SQLite specific problem in that SQLite does not have any fine grained locking mechanism. It actually locks the whole database file on write. Locking strategies for SQLite are discussed at their wiki pages, which you may want to take a look at.
It seems that part of this problem has been fixed in a later SQLite versions, see http://www.sqlite.org/cvstrac/wiki?p=DatabaseIsLocked
If you decide to test with SQLite version 3.3.7 or later, please let us know if this fix the problem for you.
Best regards -- Jan-Henrik Haukeland Mobil +47 97141255
On 30. okt. 2006, at 17.34, José Antonio Sánchez wrote:
Hello, I'm having a problem with libzdb. I have a connection pool to sqlite and I get a connection to perform a select query. Now, while processing the result set I want to update certain tables from the database. The problem is:
If I get a new connection from the pool I get a "database file is locked" so I'm gessing that a connection locks the database file while it's active. The other solution may be to use the same conection to execute the update, but that messes the result set to when it tries to get next element I get a Segmentation Fault.
Is there a way to open a "Read only" connection so it doesn't lock the entire database? If not, is there a way to make a copy of a result set to execute another query?
-- Saludos. José Antonio Sánchez
I'm using 3.3.8 version and I get the Database is locked error while trying to execute an update in the middle of a select.
On 10/30/06, Jan-Henrik Haukeland hauk@tildeslash.com wrote:
This is a SQLite specific problem in that SQLite does not have any fine grained locking mechanism. It actually locks the whole database file on write. Locking strategies for SQLite are discussed at their wiki pages, which you may want to take a look at.
It seems that part of this problem has been fixed in a later SQLite versions, see http://www.sqlite.org/cvstrac/wiki?p=DatabaseIsLocked
If you decide to test with SQLite version 3.3.7 or later, please let us know if this fix the problem for you.
Best regards
Jan-Henrik Haukeland Mobil +47 97141255
On 30. okt. 2006, at 17.34, José Antonio Sánchez wrote:
Hello, I'm having a problem with libzdb. I have a connection pool to sqlite and I get a connection to perform a select query. Now, while processing the result set I want to update certain tables from the database. The problem is:
If I get a new connection from the pool I get a "database file is locked" so I'm gessing that a connection locks the database file while it's active. The other solution may be to use the same conection to execute the update, but that messes the result set to when it tries to get next element I get a Segmentation Fault.
Is there a way to open a "Read only" connection so it doesn't lock the entire database? If not, is there a way to make a copy of a result set to execute another query?
-- Saludos. José Antonio Sánchez
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Jan-Henrik Haukeland -
José Antonio Sánchez