query_log_s Struct Reference

#include <query.h>

Data Fields
size_t	buf_size
char *	a_buf
size_t	a_buf_len
char *	b_buf
size_t	b_buf_len
char *	buf
size_t	buf_len

Detailed Description

Stucture describes a query log object.

Queries are logged into a buffer. There are two buffers, one is active, while the other one (inactive buffer) is having its data written to disk. This enables us to have no blocking operations (such as writing to disk) in the vectorloop.

Query logging thread uses channels to notify vectorloop thread when it should swap log buffers. Once VL thread swaps buffers, it sends a message back to query logging thread indicating so, which in turn signals the query logging thread that it should log data from VL inactive buffer to disk. Once data is written to disk the process repeats.

Each vectorloop thread has its own set of query log buffers.

Size of each buffer is set by configuration setting query_log_buffer_size.

Field Documentation

a_buf

char* query_log_s::a_buf

Buffer A

a_buf_len

size_t query_log_s::a_buf_len

Length of data in buffer A.

b_buf

char* query_log_s::b_buf

Buffer B

b_buf_len

size_t query_log_s::b_buf_len

Length of data in buffer B.

buf

char* query_log_s::buf

Pointer to active buffer.

buf_len

size_t query_log_s::buf_len

Length of data in active buffer.

buf_size

size_t query_log_s::buf_size

Size (capacity) of buffers.

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The documentation for this struct was generated from the following file:

• include/query.h