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MDEV-35343 unexpected replace behaviour when long unique index on

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system versioned table

For versioned table REPLACE first tries to insert a row, if it gets
duplicate key error and optimization is possible it does UPDATE +
INSERT history. If optimization is not possible it goes normal branch
for UPDATE to history and repeats the cycle of INSERT.

The failure was in normal branch when we tried UPDATE to history but
such history already exists from previous cycles. There is no such
failures in optimized branch because vers_insert_history_row() already
ignores duplicates.

The fix ignores duplicate errors for UPDATE to history and does DELETE
instead.
This commit is contained in:
Aleksey Midenkov
2025-01-13 15:40:59 +03:00
parent e1e1e50bba
commit 78c192644c
3 changed files with 50 additions and 2 deletions
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21
sql/sql_insert.cc
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@ -2126,6 +2126,9 @@ int write_record(THD *thd, TABLE *table, COPY_INFO *info, select_result *sink)
!table->file->referenced_by_foreign_key() &&
(!table->triggers || !table->triggers->has_delete_triggers()))
{
/*
Optimized dup handling via UPDATE (and insert history for versioned).
*/
if (table->versioned(VERS_TRX_ID))
{
bitmap_set_bit(table->write_set, table->vers_start_field()->field_index);
@ -2160,25 +2163,39 @@ int write_record(THD *thd, TABLE *table, COPY_INFO *info, select_result *sink)
}
else
{
/*
Normal dup handling via DELETE (or UPDATE to history for versioned)
and repeating the cycle of INSERT.
*/
if (table->triggers &&
table->triggers->process_triggers(thd, TRG_EVENT_DELETE,
TRG_ACTION_BEFORE, TRUE))
goto before_trg_err;
if (!table->versioned(VERS_TIMESTAMP))
bool do_delete= !table->versioned(VERS_TIMESTAMP);
if (do_delete)
error= table->file->ha_delete_row(table->record[1]);
else
{
/* Update existing row to history */
store_record(table, record[2]);
restore_record(table, record[1]);
table->vers_update_end();
error= table->file->ha_update_row(table->record[1],
table->record[0]);
restore_record(table, record[2]);
if (error == HA_ERR_FOUND_DUPP_KEY || /* Unique index, any SE */
error == HA_ERR_FOREIGN_DUPLICATE_KEY || /* Unique index, InnoDB */
error == HA_ERR_RECORD_IS_THE_SAME) /* No index */
{
/* Such history row was already generated from previous cycles */
error= table->file->ha_delete_row(table->record[1]);
do_delete= true;
}
}
if (unlikely(error))
goto err;
if (!table->versioned(VERS_TIMESTAMP))
if (do_delete)
info->deleted++;
else
info->updated++;