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/*-------------------------------------------------------------------------
*
* vacuum.h
* header file for postgres vacuum cleaner and statistics analyzer
*
*
* Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/commands/vacuum.h
*
*-------------------------------------------------------------------------
*/
#ifndef VACUUM_H
#define VACUUM_H
#include "access/htup.h"
#include "catalog/pg_statistic.h"
#include "catalog/pg_type.h"
#include "nodes/parsenodes.h"
#include "storage/buf.h"
#include "storage/lock.h"
#include "utils/relcache.h"
/*----------
* ANALYZE builds one of these structs for each attribute (column) that is
* to be analyzed. The struct and subsidiary data are in anl_context,
* so they live until the end of the ANALYZE operation.
*
* The type-specific typanalyze function is passed a pointer to this struct
* and must return TRUE to continue analysis, FALSE to skip analysis of this
* column. In the TRUE case it must set the compute_stats and minrows fields,
* and can optionally set extra_data to pass additional info to compute_stats.
* minrows is its request for the minimum number of sample rows to be gathered
* (but note this request might not be honored, eg if there are fewer rows
* than that in the table).
*
* The compute_stats routine will be called after sample rows have been
* gathered. Aside from this struct, it is passed:
* fetchfunc: a function for accessing the column values from the
* sample rows
* samplerows: the number of sample tuples
* totalrows: estimated total number of rows in relation
* The fetchfunc may be called with rownum running from 0 to samplerows-1.
* It returns a Datum and an isNull flag.
*
* compute_stats should set stats_valid TRUE if it is able to compute
* any useful statistics. If it does, the remainder of the struct holds
* the information to be stored in a pg_statistic row for the column. Be
* careful to allocate any pointed-to data in anl_context, which will NOT
* be CurrentMemoryContext when compute_stats is called.
*
* Note: for the moment, all comparisons done for statistical purposes
* should use the database's default collation (DEFAULT_COLLATION_OID).
* This might change in some future release.
*----------
*/
typedef struct VacAttrStats *VacAttrStatsP;
typedef Datum (*AnalyzeAttrFetchFunc) (VacAttrStatsP stats, int rownum,
bool *isNull);
typedef void (*AnalyzeAttrComputeStatsFunc) (VacAttrStatsP stats,
AnalyzeAttrFetchFunc fetchfunc,
int samplerows,
double totalrows);
typedef struct VacAttrStats
{
/*
* These fields are set up by the main ANALYZE code before invoking the
* type-specific typanalyze function.
*
* Note: do not assume that the data being analyzed has the same datatype
* shown in attr, ie do not trust attr->atttypid, attlen, etc. This is
* because some index opclasses store a different type than the underlying
* column/expression. Instead use attrtypid, attrtypmod, and attrtype for
* information about the datatype being fed to the typanalyze function.
*/
Form_pg_attribute attr; /* copy of pg_attribute row for column */
Oid attrtypid; /* type of data being analyzed */
int32 attrtypmod; /* typmod of data being analyzed */
Form_pg_type attrtype; /* copy of pg_type row for attrtypid */
MemoryContext anl_context; /* where to save long-lived data */
/*
* These fields must be filled in by the typanalyze routine, unless it
* returns FALSE.
*/
AnalyzeAttrComputeStatsFunc compute_stats; /* function pointer */
int minrows; /* Minimum # of rows wanted for stats */
void *extra_data; /* for extra type-specific data */
/*
* These fields are to be filled in by the compute_stats routine. (They
* are initialized to zero when the struct is created.)
*/
bool stats_valid;
float4 stanullfrac; /* fraction of entries that are NULL */
int32 stawidth; /* average width of column values */
float4 stadistinct; /* # distinct values */
int16 stakind[STATISTIC_NUM_SLOTS];
Oid staop[STATISTIC_NUM_SLOTS];
int numnumbers[STATISTIC_NUM_SLOTS];
float4 *stanumbers[STATISTIC_NUM_SLOTS];
int numvalues[STATISTIC_NUM_SLOTS];
Datum *stavalues[STATISTIC_NUM_SLOTS];
/*
* These fields describe the stavalues[n] element types. They will be
* initialized to match attrtypid, but a custom typanalyze function might
* want to store an array of something other than the analyzed column's
* elements. It should then overwrite these fields.
*/
Oid statypid[STATISTIC_NUM_SLOTS];
int16 statyplen[STATISTIC_NUM_SLOTS];
bool statypbyval[STATISTIC_NUM_SLOTS];
char statypalign[STATISTIC_NUM_SLOTS];
/*
* These fields are private to the main ANALYZE code and should not be
* looked at by type-specific functions.
*/
int tupattnum; /* attribute number within tuples */
HeapTuple *rows; /* access info for std fetch function */
TupleDesc tupDesc;
Datum *exprvals; /* access info for index fetch function */
bool *exprnulls;
int rowstride;
} VacAttrStats;
/*
* Parameters customizing behavior of VACUUM and ANALYZE.
*/
typedef struct VacuumParams
{
int freeze_min_age; /* min freeze age, -1 to use default */
int freeze_table_age; /* age at which to scan whole table */
int multixact_freeze_min_age; /* min multixact freeze age,
* -1 to use default */
int multixact_freeze_table_age; /* multixact age at which to
* scan whole table */
bool is_wraparound; /* force a for-wraparound vacuum */
int log_min_duration; /* minimum execution threshold in ms
* at which verbose logs are
* activated, -1 to use default */
} VacuumParams;
/* GUC parameters */
extern PGDLLIMPORT int default_statistics_target; /* PGDLLIMPORT for
* PostGIS */
extern int vacuum_freeze_min_age;
extern int vacuum_freeze_table_age;
extern int vacuum_multixact_freeze_min_age;
extern int vacuum_multixact_freeze_table_age;
/* in commands/vacuum.c */
extern void ExecVacuum(VacuumStmt *vacstmt, bool isTopLevel);
extern void vacuum(int options, RangeVar *relation, Oid relid,
VacuumParams *params, List *va_cols,
BufferAccessStrategy bstrategy, bool isTopLevel);
extern void vac_open_indexes(Relation relation, LOCKMODE lockmode,
int *nindexes, Relation **Irel);
extern void vac_close_indexes(int nindexes, Relation *Irel, LOCKMODE lockmode);
extern double vac_estimate_reltuples(Relation relation, bool is_analyze,
BlockNumber total_pages,
BlockNumber scanned_pages,
double scanned_tuples);
extern void vac_update_relstats(Relation relation,
BlockNumber num_pages,
double num_tuples,
BlockNumber num_all_visible_pages,
bool hasindex,
TransactionId frozenxid,
MultiXactId minmulti,
bool in_outer_xact);
extern void vacuum_set_xid_limits(Relation rel,
int freeze_min_age, int freeze_table_age,
int multixact_freeze_min_age,
int multixact_freeze_table_age,
TransactionId *oldestXmin,
TransactionId *freezeLimit,
TransactionId *xidFullScanLimit,
MultiXactId *multiXactCutoff,
MultiXactId *mxactFullScanLimit);
extern void vac_update_datfrozenxid(void);
extern void vacuum_delay_point(void);
/* in commands/vacuumlazy.c */
extern void lazy_vacuum_rel(Relation onerel, int options,
VacuumParams *params, BufferAccessStrategy bstrategy);
/* in commands/analyze.c */
extern void analyze_rel(Oid relid, RangeVar *relation, int options,
VacuumParams *params, List *va_cols, bool in_outer_xact,
BufferAccessStrategy bstrategy);
extern bool std_typanalyze(VacAttrStats *stats);
/* in utils/misc/sampling.c --- duplicate of declarations in utils/sampling.h */
extern double anl_random_fract(void);
extern double anl_init_selection_state(int n);
extern double anl_get_next_S(double t, int n, double *stateptr);
#endif /* VACUUM_H */
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