From c51d2044648932b6f9f32e2a8e7710716da4c220 Mon Sep 17 00:00:00 2001 From: drh Date: Tue, 30 Jul 2002 17:42:10 +0000 Subject: [PATCH] Fix for ticket #111: Update the documentation to explain that you may not start a transaction in one thread and complete it in another thread under Linux Threads where each thread has its own process ID. (CVS 695) FossilOrigin-Name: 0b0c0492cc1e55c1c4feba6e92765ea09896096c --- manifest | 14 +++++++------- manifest.uuid | 2 +- www/c_interface.tcl | 36 +++++++++++++++++++++++++++++++++++- www/faq.tcl | 8 +++++++- 4 files changed, 50 insertions(+), 10 deletions(-) diff --git a/manifest b/manifest index 38d3c3ee46..224ef7a5f2 100644 --- a/manifest +++ b/manifest @@ -1,5 +1,5 @@ -C Fix\sfor\sticket\s#71:\sCorrectly\shandle\sCR\sand\sCRLF\sline\sterminators\sin\sthe\ninput\sfiles\sfor\sthe\sCOPY\scommand.\s(CVS\s694) -D 2002-07-30T17:20:40 +C Fix\sfor\sticket\s#111:\sUpdate\sthe\sdocumentation\sto\sexplain\sthat\syou\smay\snot\r\nstart\sa\stransaction\sin\sone\sthread\sand\scomplete\sit\sin\sanother\sthread\sunder\r\nLinux\sThreads\swhere\seach\sthread\shas\sits\sown\sprocess\sID.\s(CVS\s695) +D 2002-07-30T17:42:10 F Makefile.in 6291a33b87d2a395aafd7646ee1ed562c6f2c28c F Makefile.template 4e11752e0b5c7a043ca50af4296ec562857ba495 F README a4c0ba11354ef6ba0776b400d057c59da47a4cc0 @@ -126,13 +126,13 @@ F www/arch.fig d5f9752a4dbf242e9cfffffd3f5762b6c63b3bcf F www/arch.png 82ef36db1143828a7abc88b1e308a5f55d4336f4 F www/arch.tcl 72a0c80e9054cc7025a50928d28d9c75c02c2b8b F www/audit.tcl 90e09d580f79c7efec0c7d6f447b7ec5c2dce5c0 -F www/c_interface.tcl 580c03f096a16c0cf7ce18e0483daace4a602b46 +F www/c_interface.tcl 59338ef6b9d6cff504659010a361e863f554b0ef F www/changes.tcl c920fe01975e4eac1333e075134aa857b6ebee32 F www/conflict.tcl 81dd21f9a679e60aae049e9dd8ab53d59570cda2 F www/crosscompile.tcl 3622ebbe518927a3854a12de51344673eb2dd060 F www/download.tcl 29aa6679ca29621d10613f60ebbbda18f4b91c49 F www/dynload.tcl 02eb8273aa78cfa9070dd4501dca937fb22b466c -F www/faq.tcl 06e95342a101fde3ce59dbf128233a178502587e +F www/faq.tcl 688070c1a02ceca82274675f77ef7ae723395b88 F www/formatchng.tcl 502847353450adaf76d187d87374bce20dd07e0e F www/index.tcl 17384c30e0ddccaac4cd775be4e3b18fa8a248eb F www/lang.tcl 8c3d0bda030f110c754b5edbad75eddf5dbe2ed1 @@ -142,7 +142,7 @@ F www/speed.tcl da8afcc1d3ccc5696cfb388a68982bc3d9f7f00f F www/sqlite.tcl ae3dcfb077e53833b59d4fcc94d8a12c50a44098 F www/tclsqlite.tcl 1db15abeb446aad0caf0b95b8b9579720e4ea331 F www/vdbe.tcl 2013852c27a02a091d39a766bc87cff329f21218 -P c080ed01ea51628b86050762f097e702e3aeafdf -R 2c19fd10fe86bd88ef844a3055d315b5 +P be1315755ef801b5ec07f469134e0d33a3ece990 +R a079c5e56f534c0ce7676afdebb45812 U drh -Z e835230fdc0a66edc7f339264e4e0fbb +Z 60f9e91154609c6dea4c51f07544d2bf diff --git a/manifest.uuid b/manifest.uuid index 07f49780d9..ba1b3a83c8 100644 --- a/manifest.uuid +++ b/manifest.uuid @@ -1 +1 @@ -be1315755ef801b5ec07f469134e0d33a3ece990 \ No newline at end of file +0b0c0492cc1e55c1c4feba6e92765ea09896096c \ No newline at end of file diff --git a/www/c_interface.tcl b/www/c_interface.tcl index 0ef966b061..f8169e83e3 100644 --- a/www/c_interface.tcl +++ b/www/c_interface.tcl @@ -1,7 +1,7 @@ # # Run this Tcl script to generate the sqlite.html file. # -set rcsid {$Id: c_interface.tcl,v 1.31 2002/07/13 17:18:37 drh Exp $} +set rcsid {$Id: c_interface.tcl,v 1.32 2002/07/30 17:42:10 drh Exp $} puts { @@ -301,6 +301,9 @@ is used incorrectly. Examples of incorrect usage include calling sqlite_exec() after the database has been closed using sqlite_close() or calling sqlite_exec() with the same database pointer simultaneously from two separate threads. +This error code will also be returned under Unix if sqlite_exec() +is called while a transaction is pending that was started in another +process or thread that has a different process ID.

@@ -792,6 +795,37 @@ new SQL functions, review the SQLite source code in the file func.c.

+

Multi-Threading And SQLite

+ +

+If SQLite is compiled with the THREADSAFE preprocessor macro set to 1, +then it is safe to use SQLite from two or more threads of the same process +at the same time. But each thread should have its own sqlite* +pointer returned from sqlite_open(). It is never safe for two +or more threads to access the same sqlite* pointer at the same time. +

+ +

+In precompiled SQLite libraries available on the website, the Unix +versions are compiled with THREADSAFE turned off but the windows +versions are compiled with THREADSAFE turned on. If you need something +different that this you will have to recompile. +

+ +

+Under Unix, an sqlite* pointer should not be carried across a +fork() system call into the child process. The child process +should open its own copy of the database after the fork(). +

+ +

+When using LinuxThreads (where each thread has its own process ID) +it is illegal to start a transaction in one thread and then attempt +to read or write the database from a different thread. This +restriction does not apply to Posix threads where all threads share +the same process ID. +

+

Usage Examples

For examples of how the SQLite C/C++ interface can be used, diff --git a/www/faq.tcl b/www/faq.tcl index 68e332b716..63e2e95623 100644 --- a/www/faq.tcl +++ b/www/faq.tcl @@ -1,7 +1,7 @@ # # Run this script to generated a faq.html output file # -set rcsid {$Id: faq.tcl,v 1.11 2002/06/25 01:09:13 drh Exp $} +set rcsid {$Id: faq.tcl,v 1.12 2002/07/30 17:42:10 drh Exp $} puts { @@ -231,6 +231,12 @@ faq { not be able to see the new table right away. You might have to get the other threads to close and reopen their connection to the database before they will be able to see the new table.

+ +

Under UNIX, you should not carry an open SQLite database across + a fork() system call into the child process. Problems will result + if you do. Under LinuxThreads, because each thread has its own + process ID, you may not start a transaction in one thread and attempt + to complete it in another.

} faq {