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Overview
| Comment: | Update documentation for sqlite3_snapshot_open(). No code changes. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
1dfa5234d3ee38c6af2d18a6294afa93 |
| User & Date: | drh 2016-04-08 19:44:31 |
Context
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2016-04-09
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| 14:36 | Limit the number of digits shown in the "prereq" mask for ".wheretrace" debugging output. (check-in: 3686ed74 user: drh tags: trunk) | |
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2016-04-08
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| 21:35 | Attempt to treat the arguments to a table-valued function as if they occur in the ON clause of a LEFT JOIN rather than in the WHERE clause. But this causes undesirable behavior with generate_series, as demonstrated by test cases. This is an incremental check-in pending further work. (Leaf check-in: 00ac73a0 user: drh tags: tabfunc-in-left-join) | |
| 19:44 | Update documentation for sqlite3_snapshot_open(). No code changes. (check-in: 1dfa5234 user: drh tags: trunk) | |
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2016-04-07
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| 21:14 | Add test cases for ticket [7f7f8026eda387d544]. (check-in: 87aa9357 user: drh tags: trunk) | |
Changes
Changes to src/sqlite.h.in.
8077 8077 sqlite3_snapshot **ppSnapshot 8078 8078 ); 8079 8079 8080 8080 /* 8081 8081 ** CAPI3REF: Start a read transaction on an historical snapshot 8082 8082 ** EXPERIMENTAL 8083 8083 ** 8084 -** ^The [sqlite3_snapshot_open(D,S,P)] interface attempts to move the 8085 -** read transaction that is currently open on schema S of 8086 -** [database connection] D so that it refers to historical [snapshot] P. 8084 +** ^The [sqlite3_snapshot_open(D,S,P)] interface starts a 8085 +** read transaction for schema S of 8086 +** [database connection] D such that the read transaction 8087 +** refers to historical [snapshot] P, rather than the most 8088 +** recent change to the database. 8087 8089 ** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success 8088 8090 ** or an appropriate [error code] if it fails. 8089 8091 ** 8090 8092 ** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be 8091 -** the first operation, apart from other sqlite3_snapshot_open() calls, 8092 -** following the [BEGIN] that starts a new read transaction. 8093 -** ^A [snapshot] will fail to open if it has been overwritten by a 8093 +** the first operation following the [BEGIN] that takes the schema S 8094 +** out of [autocommit mode]. 8095 +** ^In other words, schema S must not currently be in 8096 +** a transaction for [sqlite3_snapshot_open(D,S,P)] to work, but the 8097 +** database connection D must be out of [autocommit mode]. 8098 +** ^A [snapshot] will fail to open if it has been overwritten by a 8094 8099 ** [checkpoint]. 8095 -** ^A [snapshot] will fail to open if the database connection D has not 8096 -** previously completed at least one read operation against the database 8097 -** file. (Hint: Run "[PRAGMA application_id]" against a newly opened 8100 +** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 8101 +** database connection D does not know that the database file for 8102 +** schema S is in [WAL mode]. A database connection might not know 8103 +** that the database file is in [WAL mode] if there has been no prior 8104 +** I/O on that database connection, or if the database entered [WAL mode] 8105 +** after the most recent I/O on the database connection.)^ 8106 +** (Hint: Run "[PRAGMA application_id]" against a newly opened 8098 8107 ** database connection in order to make it ready to use snapshots.) 8099 8108 ** 8100 8109 ** The [sqlite3_snapshot_open()] interface is only available when the 8101 8110 ** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8102 8111 */ 8103 8112 SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 8104 8113 sqlite3 *db,