GLOBAL_DOUBLE_WRITE_STATUS

GLOBAL_DOUBLE_WRITE_STATUS displays doublewrite file status of all instances in MogDB. It consists of the local_double_write_stat view of each node. Columns in the view on each node are the same.

Table 1 GLOBAL_DOUBLE_WRITE_STATUS columns

Name	Type	Description
node_name	text	Node name
curr_dwn	bigint	Sequence number of the doublewrite file
curr_start_page	bigint	Start page for restoring the doublewrite file
file_trunc_num	bigint	Number of times that the doublewrite file is reused
file_reset_num	bigint	Number of reset times after the doublewrite file is full
total_writes	bigint	Total number of I/Os of the doublewrite file
low_threshold_writes	bigint	Number of I/Os for writing doublewrite files with low efficiency (the number of I/O flushing pages at a time is less than 16)
high_threshold_writes	bigint	Number of I/Os for writing doublewrite files with high efficiency (the number of I/O flushing pages at a time is more than 421)
total_pages	bigint	Total number of pages that are flushed to the doublewrite file area
low_threshold_pages	bigint	Number of pages that are flushed with low efficiency
high_threshold_pages	bigint	Number of pages that are flushed with high efficiency
file_id	bigint	ID of the current doublewrite file