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Manually delete physical files for ENR entries when leaving scope. #450

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merged 6 commits into from
Sep 27, 2024
Merged

Manually delete physical files for ENR entries when leaving scope. #450

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f22b9e4
Add separate list to track pending deletes for TSQL ENR entries.
Sep 25, 2024
07883d2
Revert "Add separate list to track pending deletes for TSQL ENR entri…
Sep 26, 2024
cfe56aa
Manually delete physical files for ENR entries when leaving scope.
Sep 26, 2024
e766461
Clean up some code logic.
Sep 26, 2024
351db1c
Merge remote-tracking branch 'upstream/BABEL_4_X_DEV__PG_16_X' into j…
Sep 26, 2024
516a19b
Merge remote-tracking branch 'upstream/BABEL_4_X_DEV__PG_16_X' into j…
Sep 27, 2024
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51 changes: 48 additions & 3 deletions src/backend/utils/misc/queryenvironment.c
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Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,7 @@
#include "catalog/pg_shdepend.h"
#include "catalog/pg_index_d.h"
#include "parser/parser.h" /* only needed for GUC variables */
#include "storage/smgr.h"
#include "utils/inval.h"
#include "utils/guc.h"
#include "utils/syscache.h"
Expand Down Expand Up @@ -1549,9 +1550,12 @@ bool useTempOidBufferForOid(Oid relId)
void
ENRDropTempTables(QueryEnvironment *queryEnv)
{
ListCell *lc = NULL;
ObjectAddress object;
ObjectAddresses *objects;
ListCell *lc = NULL;
ObjectAddress object;
ObjectAddresses *objects;
int nrels = 0,
maxrels = 0;
SMgrRelation *srels = NULL;

if (!queryEnv)
return;
Expand All @@ -1564,6 +1568,8 @@ ENRDropTempTables(QueryEnvironment *queryEnv)
foreach(lc, queryEnv->namedRelList)
{
EphemeralNamedRelation enr = (EphemeralNamedRelation) lfirst(lc);
Relation rel;
SMgrRelation srel;

if (enr->md.enrtype != ENR_TSQL_TEMP)
continue;
Expand All @@ -1572,6 +1578,45 @@ ENRDropTempTables(QueryEnvironment *queryEnv)
object.objectSubId = 0;
object.objectId = enr->md.reliddesc;
add_exact_object_address(&object, objects);
/*
* Delete the physical storage for the relation.
* See: smgrDoPendingDeletes()
*/
rel = relation_open(enr->md.reliddesc, AccessExclusiveLock);
srel = smgropen(rel->rd_locator, rel->rd_backend);

/* allocate the initial array, or extend it, if needed */
if (maxrels == 0)
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why are we doing this? we have single relationship, we should just pass pointer to that relation with count as 1 to smgrdounlinkall

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We do not necessarily only have one relation - there can be multiple table variables and temp tables defined in the same scope, which would all be cleaned up at once by this function.

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Correction: currently table variables are being cleaned up prior to this function during pltsql_clean_table_variables(), which manually executes a DROP TABLE statement to drop the table variable. Since that function only registers the physical file for deletion at transaction rather than immediately, we probably should remove that function and let this function do both table variable and temp table cleanup, but that can be done in a later commit.

TLDR: currently only temp tables in scope are being cleaned up here, and not table variables, which are handled separately.

{
maxrels = 8;
srels = palloc(sizeof(SMgrRelation) * maxrels);
}
else if (maxrels <= nrels)
{
maxrels *= 2;
srels = repalloc(srels, sizeof(SMgrRelation) * maxrels);
}

srels[nrels++] = srel;

relation_close(rel, NoLock);
}

/*
* The below call to performMultpleDeletions() only registers the
* underlying files for deletion at the end of transaction, but they
* need to be deleted now since we are exiting the current scope. We
* still need to run the function though, to make sure that all of the
* dependencies are properly cleaned up.
*/
if (nrels > 0)
{
smgrdounlinkall(srels, nrels, false);

for (int i = 0; i < nrels; i++)
smgrclose(srels[i]);

pfree(srels);
}

/*
Expand Down
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