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Overview
Comment: | Clarify the handling of the sqlite_stat1 table by legacy versions of the sessions module. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | sessions-stat1 |
Files: | files | file ages | folders |
SHA3-256: |
dc7c48cb4126db9e25c73512cc743155 |
User & Date: | dan 2018-01-18 16:56:19.115 |
Context
2018-01-18
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16:59 | Fix sessions module handling of sqlite_stat1 rows with (idx IS NULL). (check-in: 0e91641633 user: dan tags: trunk) | |
16:56 | Clarify the handling of the sqlite_stat1 table by legacy versions of the sessions module. (Closed-Leaf check-in: dc7c48cb41 user: dan tags: sessions-stat1) | |
16:53 | Add comments describing the special sqlite_stat1 handling to sqlite3session.h. (check-in: 4431a3256f user: dan tags: sessions-stat1) | |
Changes
Changes to ext/session/sqlite3session.h.
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146 147 148 149 150 151 152 | ** in one or more of their PRIMARY KEY columns. ** ** SQLITE_OK is returned if the call completes without error. Or, if an error ** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned. ** ** <h3>Special sqlite_stat1 Handling</h3> ** | | | > > > > > | 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 | ** in one or more of their PRIMARY KEY columns. ** ** SQLITE_OK is returned if the call completes without error. Or, if an error ** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned. ** ** <h3>Special sqlite_stat1 Handling</h3> ** ** As of SQLite version 3.22.0, the "sqlite_stat1" table is an exception to ** some of the rules above. In SQLite, the schema of sqlite_stat1 is: ** <pre> ** CREATE TABLE sqlite_stat1(tbl,idx,stat) ** </pre> ** ** Even though sqlite_stat1 does not have a PRIMARY KEY, changes are ** recorded for it as if the PRIMARY KEY is (tbl,idx). Additionally, changes ** are recorded for rows for which (idx IS NULL) is true. However, for such ** rows a zero-length blob (SQL value X'') is stored in the changeset or ** patchset instead of a NULL value. This allows such changesets to be ** manipulated by legacy implementations of sqlite3changeset_invert(), ** concat() and similar. ** ** The sqlite3changeset_apply() function automatically converts the ** zero-length blob back to a NULL value when updating the sqlite_stat1 ** table. However, if the application calls sqlite3changeset_new(), ** sqlite3changeset_old() or sqlite3changeset_conflict on a changeset ** iterator directly (including on a changeset iterator passed to a ** conflict-handler callback) then the X'' value is returned. The application ** must translate X'' to NULL itself if required. ** ** Legacy (older than 3.22.0) versions of the sessions module cannot capture ** changes made to the sqlite_stat1 table. Legacy versions of the ** sqlite3changeset_apply() function silently ignore any modifications to the ** sqlite_stat1 table that are part of a changeset or patchset. */ int sqlite3session_attach( sqlite3_session *pSession, /* Session object */ const char *zTab /* Table name */ ); /* |
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