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eedee45885
The reason for the crash was that two tables where updating Aria's TRN->used_instances at the same time. This could happen when a thread started a sub transaction with Aria tables, like reading a stored procedure from the proc table, at the same time another table was clearing the table list after committing a transaction involving Aria tables. The timing window for this to happen is very small, which is why we did not notice this issue for 5 years. The fix was to change reset_thd_trn() to clear the table links directly, instead of calling _ma_reset_trn_for_table() which removed the table from the linked list, which included updating TRN->used_instances. This bug could happen when maria_commit or maria_rollback() where called but not in ha_maria::implicit_commit() which had already a fix for this problem. Other things: - Removed duplicate call to thd_set_ha_data(thd, maria_hton, trn) in ha_maria::implicit_commit() and maria_commit() when TRN is null.
128 lines
3.8 KiB
C
128 lines
3.8 KiB
C
/* Copyright (C) 2006-2008 MySQL AB, 2008-2009 Sun Microsystems, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */
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#ifndef _ma_trnman_h
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#define _ma_trnman_h
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/**
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Sets table's trn and prints debug information
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Links table into new_trn->used_instances
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@param tbl MARIA_HA of table
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@param newtrn what to put into tbl->trn
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*/
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static inline void _ma_set_trn_for_table(MARIA_HA *tbl, TRN *newtrn)
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{
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DBUG_PRINT("info",("table: %p trn: %p -> %p",
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tbl, tbl->trn, newtrn));
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/* check that we are not calling this twice in a row */
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DBUG_ASSERT(newtrn->used_instances != (void*) tbl);
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DBUG_ASSERT(newtrn != &dummy_transaction_object);
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DBUG_ASSERT(tbl->trn == 0);
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DBUG_ASSERT(tbl->trn_next == 0);
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DBUG_ASSERT(tbl->trn_prev == 0);
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tbl->trn= newtrn;
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/* Link into used list */
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if (newtrn->used_instances)
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((MARIA_HA*) newtrn->used_instances)->trn_prev= &tbl->trn_next;
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tbl->trn_next= (MARIA_HA*) newtrn->used_instances;
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tbl->trn_prev= (MARIA_HA**) &newtrn->used_instances;
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newtrn->used_instances= tbl;
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}
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/*
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Same as _ma_set_trn_for_table(), but don't link table into used_instance list
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Used when we want to temporary set trn for a table in extra()
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*/
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static inline void _ma_set_tmp_trn_for_table(MARIA_HA *tbl, TRN *newtrn)
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{
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DBUG_PRINT("info",("table: %p trn: %p -> %p",
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tbl, tbl->trn, newtrn));
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tbl->trn= newtrn;
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tbl->trn_prev= 0;
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tbl->trn_next= 0; /* To avoid assert in ha_maria::close() */
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}
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/*
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Reset TRN in table
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*/
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static inline void _ma_reset_trn_for_table(MARIA_HA *tbl)
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{
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TRN *trn __attribute__((unused))= tbl->trn;
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DBUG_PRINT("info",("table: %p trn: %p -> NULL", tbl, tbl->trn));
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/* The following is only false if tbl->trn == &dummy_transaction_object */
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if (tbl->trn_prev)
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{
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if (tbl->trn_next)
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{
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DBUG_ASSERT(tbl->trn_next->trn == trn);
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tbl->trn_next->trn_prev= tbl->trn_prev;
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}
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*tbl->trn_prev= tbl->trn_next;
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tbl->trn_prev= 0;
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tbl->trn_next= 0;
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}
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else
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{
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DBUG_ASSERT(tbl->trn_next == 0);
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}
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tbl->trn= 0;
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}
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/*
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Take over the used_instances link from a trn object
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Reset the link in the trn object
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*/
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static inline void relink_trn_used_instances(MARIA_HA **used_tables, TRN *trn)
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{
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if (likely(*used_tables= (MARIA_HA*) trn->used_instances))
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{
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/* Check that first back link is correct */
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DBUG_ASSERT((*used_tables)->trn_prev == (MARIA_HA **)&trn->used_instances);
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/* Fix back link to point to new base for the list */
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(*used_tables)->trn_prev= used_tables;
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trn->used_instances= 0;
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}
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}
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/**
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When we want to check a table, we verify that the transaction ids of rows
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and keys are not bigger than the biggest id generated by Maria so far, which
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is returned by the function below.
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@note If control file is not open, 0 may be returned; to not confuse
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this with a valid max trid of 0, the caller should notice that it failed to
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open the control file (ma_control_file_inited() can serve for that).
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*/
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static inline TrID max_trid_in_system(void)
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{
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TrID id= trnman_get_max_trid(); /* 0 if transac manager not initialized */
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/* 'id' may be far bigger, if last shutdown is old */
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return MY_MAX(id, max_trid_in_control_file);
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}
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#endif /* _ma_trnman_h */
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