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/******************************************************
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Created 2/16/1997 Heikki Tuuri
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*******************************************************/
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#include "read0types.h"
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/*************************************************************************
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Opens a read view where exactly the transactions serialized before this
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point in time are seen in the view. */
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/* out, own: read view struct */
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dulint cr_trx_id, /* in: trx_id of creating
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transaction, or (0, 0) used in
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mem_heap_t* heap); /* in: memory heap from which
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/*************************************************************************
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Makes a copy of the oldest existing read view, or opens a new. The view
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must be closed with ..._close. */
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read_view_oldest_copy_or_open_new(
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/*==============================*/
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/* out, own: read view struct */
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dulint cr_trx_id, /* in: trx_id of creating
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transaction, or (0, 0) used in
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mem_heap_t* heap); /* in: memory heap from which
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/*************************************************************************
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Closes a read view. */
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read_view_t* view); /* in: read view */
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/*************************************************************************
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Closes a consistent read view for MySQL. This function is called at an SQL
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statement end if the trx isolation level is <= TRX_ISO_READ_COMMITTED. */
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read_view_close_for_mysql(
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/*======================*/
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trx_t* trx); /* in: trx which has a read view */
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/*************************************************************************
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Checks if a read view sees the specified transaction. */
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read_view_sees_trx_id(
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/*==================*/
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/* out: TRUE if sees */
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read_view_t* view, /* in: read view */
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dulint trx_id);/* in: trx id */
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/*************************************************************************
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Prints a read view to stderr. */
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read_view_t* view); /* in: read view */
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/*************************************************************************
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Create a consistent cursor view for mysql to be used in cursors. In this
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consistent read view modifications done by the creating transaction or future
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transactions are not visible. */
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read_cursor_view_create_for_mysql(
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/*==============================*/
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trx_t* cr_trx);/* in: trx where cursor view is created */
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/*************************************************************************
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Close a given consistent cursor view for mysql and restore global read view
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back to a transaction read view. */
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read_cursor_view_close_for_mysql(
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/*=============================*/
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trx_t* trx, /* in: trx */
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cursor_view_t* curview); /* in: cursor view to be closed */
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/*************************************************************************
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This function sets a given consistent cursor view to a transaction
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read view if given consistent cursor view is not NULL. Otherwise, function
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restores a global read view to a transaction read view. */
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read_cursor_set_for_mysql(
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/*======================*/
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trx_t* trx, /* in: transaction where cursor is set */
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cursor_view_t* curview);/* in: consistent cursor view to be set */
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/* Read view lists the trx ids of those transactions for which a consistent
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read should not see the modifications to the database. */
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struct read_view_struct{
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ulint type; /* VIEW_NORMAL, VIEW_HIGH_GRANULARITY */
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dulint undo_no; /* (0, 0) or if type is VIEW_HIGH_GRANULARITY
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transaction undo_no when this high-granularity
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consistent read view was created */
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dulint low_limit_no; /* The view does not need to see the undo
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logs for transactions whose transaction number
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is strictly smaller (<) than this value: they
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can be removed in purge if not needed by other
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dulint low_limit_id; /* The read should not see any transaction
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with trx id >= this value */
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dulint up_limit_id; /* The read should see all trx ids which
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are strictly smaller (<) than this value */
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ulint n_trx_ids; /* Number of cells in the trx_ids array */
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dulint* trx_ids; /* Additional trx ids which the read should
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not see: typically, these are the active
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transactions at the time when the read is
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serialized, except the reading transaction
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itself; the trx ids in this array are in a
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dulint creator_trx_id; /* trx id of creating transaction, or
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(0, 0) used in purge */
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UT_LIST_NODE_T(read_view_t) view_list;
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/* List of read views in trx_sys */
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/* Read view types */
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#define VIEW_NORMAL 1 /* Normal consistent read view
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where transaction does not see changes
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made by active transactions except
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creating transaction. */
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#define VIEW_HIGH_GRANULARITY 2 /* High-granularity read view where
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transaction does not see changes
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made by active transactions and own
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changes after a point in time when this
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read view was created. */
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/* Implement InnoDB framework to support consistent read views in
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cursors. This struct holds both heap where consistent read view
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is allocated and pointer to a read view. */
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struct cursor_view_struct{
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/* Memory heap for the cursor view */
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read_view_t* read_view;
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/* Consistent read view of the cursor*/
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ulint n_mysql_tables_in_use;
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/* number of Innobase tables used in the
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processing of this cursor */
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#include "read0read.ic"
added
removed
storage/innobase/include/read0read.h
