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mirror/mariadb

mirror of https://github.com/MariaDB/server.git synced 2025-01-22 06:44:16 +01:00

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Fixed bug#36676: multiupdate using LEFT JOIN updates only first row or fails with an error: ERROR 1022 (23000): Can't write; duplicate key in table '' The server uses intermediate temporary table to store updated row data. The first column of this table contains rowid. Current server implementation doesn't reset NULL flag of that column even if the server fills a column with rowid. To keep each rowid unique, there is an unique index. An insertion into an unique index takes into account NULL flag of key value and ignores real data if NULL flag is set. So, insertion of actually different rowids may lead to two kind of problems. Visible effect of each of these problems depends on an initial engine type of temporary table: 1. If multiupdate initially creates temporary table as a MyISAM table (a table contains blob columns, and the create_tmp_table function assumes, that this table is large), it inserts only one single row and updates only rows with one corresponding rowid. Other rows are silently ignored. 2. If multiupdate initially creates MEMORY temporary table, fills it with data and reaches size limit for MEMORY tables (max_heap_table_size), multiupdate converts MEMORY table into MyISAM table and fails with an error: ERROR 1022 (23000): Can't write; duplicate key in table '' Multiupdate has been fixed to update the NULL flag of temporary table rowid columns.

2008-05-18 14:21:25 +05:00

--set-variable=max_heap_table_size=16384