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Revert b6002a796

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This removes "Add Result Cache executor node".  It seems that something
weird is going on with the tracking of cache hits and misses as
highlighted by many buildfarm animals.  It's not yet clear what the
problem is as other parts of the plan indicate that the cache did work
correctly, it's just the hits and misses that were being reported as 0.

This is especially a bad time to have the buildfarm so broken, so
reverting before too many more animals go red.

Discussion: https://postgr.es/m/CAApHDvq_hydhfovm4=izgWs+C5HqEeRScjMbOgbpC-jRAeK3Yw@mail.gmail.com
This commit is contained in:
David Rowley
2021-04-01 13:33:23 +13:00
parent b6002a796d
commit 28b3e3905c
45 changed files with 196 additions and 2833 deletions
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66
src/include/nodes/execnodes.h
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@ -17,7 +17,6 @@
#include "access/tupconvert.h"
#include "executor/instrument.h"
#include "fmgr.h"
#include "lib/ilist.h"
#include "lib/pairingheap.h"
#include "nodes/params.h"
#include "nodes/plannodes.h"
@ -2038,71 +2037,6 @@ typedef struct MaterialState
Tuplestorestate *tuplestorestate;
} MaterialState;
struct ResultCacheEntry;
struct ResultCacheTuple;
struct ResultCacheKey;
typedef struct ResultCacheInstrumentation
{
uint64 cache_hits; /* number of rescans where we've found the
* scan parameter values to be cached */
uint64 cache_misses; /* number of rescans where we've not found the
* scan parameter values to be cached. */
uint64 cache_evictions; /* number of cache entries removed due to
* the need to free memory */
uint64 cache_overflows; /* number of times we've had to bypass the
* cache when filling it due to not being
* able to free enough space to store the
* current scan's tuples. */
uint64 mem_peak; /* peak memory usage in bytes */
} ResultCacheInstrumentation;
/* ----------------
* Shared memory container for per-worker resultcache information
* ----------------
*/
typedef struct SharedResultCacheInfo
{
int num_workers;
ResultCacheInstrumentation sinstrument[FLEXIBLE_ARRAY_MEMBER];
} SharedResultCacheInfo;
/* ----------------
* ResultCacheState information
*
* resultcache nodes are used to cache recent and commonly seen results
* from a parameterized scan.
* ----------------
*/
typedef struct ResultCacheState
{
ScanState ss; /* its first field is NodeTag */
int rc_status; /* value of ExecResultCache state machine */
int nkeys; /* number of cache keys */
struct resultcache_hash *hashtable; /* hash table for cache entries */
TupleDesc hashkeydesc; /* tuple descriptor for cache keys */
TupleTableSlot *tableslot; /* min tuple slot for existing cache entries */
TupleTableSlot *probeslot; /* virtual slot used for hash lookups */
ExprState *cache_eq_expr; /* Compare exec params to hash key */
ExprState **param_exprs; /* exprs containing the parameters to this
* node */
FmgrInfo *hashfunctions; /* lookup data for hash funcs nkeys in size */
Oid *collations; /* collation for comparisons nkeys in size */
uint64 mem_used; /* bytes of memory used by cache */
uint64 mem_limit; /* memory limit in bytes for the cache */
MemoryContext tableContext; /* memory context to store cache data */
dlist_head lru_list; /* least recently used entry list */
struct ResultCacheTuple *last_tuple; /* Used to point to the last tuple
* returned during a cache hit and
* the tuple we last stored when
* populating the cache. */
struct ResultCacheEntry *entry; /* the entry that 'last_tuple' belongs to
* or NULL if 'last_tuple' is NULL. */
bool singlerow; /* true if the cache entry is to be marked as
* complete after caching the first tuple. */
ResultCacheInstrumentation stats; /* execution statistics */
SharedResultCacheInfo *shared_info; /* statistics for parallel workers */
} ResultCacheState;
/* ----------------
* When performing sorting by multiple keys, it's possible that the input