postgres-backend.c File Reference

Macros
#define	__XCHANGE_INTERNAL_API__
	Use internal definitions.
#define	_GNU_SOURCE
	C source code standard.
#define	COL_NAME_STEM   "c"
	prefix for array data columns
#define	DEFAULT_STRING_LEN   16
	(bytes) default initial size for variable-length strings
#define	FIX_SCALAR_DIMS   0
	Whether singled-element 1D data should be stored as scalars.
#define	MASTER_TABLE   "titles"
	table name in which to store variable name -> id pairings
#define	META_NAME_PATTERN   TABLE_NAME_PATTERN "_meta"
	pattern for metadata table names
#define	META_SERIAL_ID   "serial"
	column name/id for metadata serial numbers
#define	META_SHAPE_LEN   X_MAX_STRING_DIMS
	Maximum number of dimensions to store.
#define	META_UNIT_LEN   32
	Maximum size for sotring physical units.
#define	MIN_CMD_SIZE   16384
	(bytes) Initial size of the command buffer
#define	POSTGRES   1
	Use PostgreSQL data types from sql-types.h.
#define	SQL_COL_NAME_LEN   32
	(bytes) Maximum length for column names
#define	SQL_SEP   ", "
	List separator.
#define	SQL_TABLE_NAME_LEN   32
	(bytes) Maximum length for table names
#define	SQL_TYPE_LEN   64
	(bytes) Maximum length of SQL data type names
#define	TABLE_NAME_PATTERN   "var_%06d"
	pattern for tables names that store data for variables
#define	VARNAME_ID   "name"
	column name/id for variable names

Functions
int	deleteVars (const char *pattern)
int	insertQueue (Variable *u)
int	setupDB (const char *owner, const char *passwd)
void *	SQLThread ()

Detailed Description

Date

Created on Nov 5, 2023

Author

Attila Kovacs

SQL backend module for smaxLogger. It supports most common SQL flavors. The specific SQL flavor to use can be selected via an appropriate compiler constant.

Function Documentation

deleteVars()

int deleteVars

(

const char *

pattern

)

Deletes variables and metadata from the SQL DB, and removes them from the master table also.

Parameters

pattern

Glob variable name pattern

Returns

The number of variables deleted from the SQL DB, or -1 if there was an error (errno will indicate the type of error).

References MASTER_TABLE.

insertQueue()

int insertQueue

(

Variable *

u

)

Add the variable to the queue for database insertion.

Parameters

u	Pointer to the variable data structure

Returns

SUCCESS_RETURN (0) if successful, or else ERROR_RETURN (-1; errno will indicate the type of error).

References ERROR_RETURN, Variable::next, and SUCCESS_RETURN.

setupDB()

int setupDB	(	const char *	owner,
		const char *	passwd
	)

Sets up (bootstraps) a clean new database

Parameters

owner	User that will own the database (it must have privileges for creating the database)
passwd	Password for oqner

Returns

SUUCCESS_RETURN if successful, or else ERROR_RETURN.

References IDLE_STATE.

SQLThread()

void * SQLThread

(

)

The main processing thread, which pulls values from the queue and inserts them into the database asynchronously. It is started up by initialize();

Returns

NULL

References CONNECT_RETRY_ATTEMPTS, destroyVariable(), ERROR_EXIT, IDLE_STATE, META_NAME_PATTERN, Variable::next, SQL_TABLE_NAME_LEN, SUCCESS_RETURN, and TRUE.