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Restructure ALTER TABLE execution to fix assorted bugs.

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We've had numerous bug reports about how (1) IF NOT EXISTS clauses in
ALTER TABLE don't behave as-expected, and (2) combining certain actions
into one ALTER TABLE doesn't work, though executing the same actions as
separate statements does.  This patch cleans up all of the cases so far
reported from the field, though there are still some oddities associated
with identity columns.

The core problem behind all of these bugs is that we do parse analysis
of ALTER TABLE subcommands too soon, before starting execution of the
statement.  The root of the bugs in group (1) is that parse analysis
schedules derived commands (such as a CREATE SEQUENCE for a serial
column) before it's known whether the IF NOT EXISTS clause should cause
a subcommand to be skipped.  The root of the bugs in group (2) is that
earlier subcommands may change the catalog state that later subcommands
need to be parsed against.

Hence, postpone parse analysis of ALTER TABLE's subcommands, and do
that one subcommand at a time, during "phase 2" of ALTER TABLE which
is the phase that does catalog rewrites.  Thus the catalog effects
of earlier subcommands are already visible when we analyze later ones.
(The sole exception is that we do parse analysis for ALTER COLUMN TYPE
subcommands during phase 1, so that their USING expressions can be
parsed against the table's original state, which is what we need.
Arguably, these bugs stem from falsely concluding that because ALTER
COLUMN TYPE must do early parse analysis, every other command subtype
can too.)

This means that ALTER TABLE itself must deal with execution of any
non-ALTER-TABLE derived statements that are generated by parse analysis.
Add a suitable entry point to utility.c to accept those recursive
calls, and create a struct to pass through the information needed by
the recursive call, rather than making the argument lists of
AlterTable() and friends even longer.

Getting this to work correctly required a little bit of fiddling
with the subcommand pass structure, in particular breaking up
AT_PASS_ADD_CONSTR into multiple passes.  But otherwise it's mostly
a pretty straightforward application of the above ideas.

Fixing the residual issues for identity columns requires refactoring of
where the dependency link from an identity column to its sequence gets
set up.  So that seems like suitable material for a separate patch,
especially since this one is pretty big already.

Discussion: https://postgr.es/m/10365.1558909428@sss.pgh.pa.us
This commit is contained in:
Tom Lane
2020-01-15 18:49:24 -05:00
parent a166d408eb
commit 1281a5c907
13 changed files with 827 additions and 267 deletions
Download Patch File Download Diff File Expand all files Collapse all files

494
src/backend/commands/tablecmds.c
View File

@ -85,6 +85,7 @@
#include "storage/lock.h"
#include "storage/predicate.h"
#include "storage/smgr.h"
#include "tcop/utility.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
@ -142,11 +143,13 @@ static List *on_commits = NIL;
#define AT_PASS_OLD_CONSTR 3 /* re-add existing constraints */
/* We could support a RENAME COLUMN pass here, but not currently used */
#define AT_PASS_ADD_COL 4 /* ADD COLUMN */
#define AT_PASS_COL_ATTRS 5 /* set other column attributes */
#define AT_PASS_ADD_INDEX 6 /* ADD indexes */
#define AT_PASS_ADD_CONSTR 7 /* ADD constraints, defaults */
#define AT_PASS_MISC 8 /* other stuff */
#define AT_NUM_PASSES 9
#define AT_PASS_ADD_CONSTR 5 /* ADD constraints (initial examination) */
#define AT_PASS_COL_ATTRS 6 /* set column attributes, eg NOT NULL */
#define AT_PASS_ADD_INDEXCONSTR 7 /* ADD index-based constraints */
#define AT_PASS_ADD_INDEX 8 /* ADD indexes */
#define AT_PASS_ADD_OTHERCONSTR 9 /* ADD other constraints, defaults */
#define AT_PASS_MISC 10 /* other stuff */
#define AT_NUM_PASSES 11
typedef struct AlteredTableInfo
{
@ -159,6 +162,7 @@ typedef struct AlteredTableInfo
/* Information saved by Phases 1/2 for Phase 3: */
List *constraints; /* List of NewConstraint */
List *newvals; /* List of NewColumnValue */
List *afterStmts; /* List of utility command parsetrees */
bool verify_new_notnull; /* T if we should recheck NOT NULL */
int rewrite; /* Reason for forced rewrite, if any */
Oid newTableSpace; /* new tablespace; 0 means no change */
@ -340,31 +344,45 @@ static void validateForeignKeyConstraint(char *conname,
Relation rel, Relation pkrel,
Oid pkindOid, Oid constraintOid);
static void ATController(AlterTableStmt *parsetree,
Relation rel, List *cmds, bool recurse, LOCKMODE lockmode);
Relation rel, List *cmds, bool recurse, LOCKMODE lockmode,
AlterTableUtilityContext *context);
static void ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
bool recurse, bool recursing, LOCKMODE lockmode);
static void ATRewriteCatalogs(List **wqueue, LOCKMODE lockmode);
bool recurse, bool recursing, LOCKMODE lockmode,
AlterTableUtilityContext *context);
static void ATRewriteCatalogs(List **wqueue, LOCKMODE lockmode,
AlterTableUtilityContext *context);
static void ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
AlterTableCmd *cmd, LOCKMODE lockmode);
AlterTableCmd *cmd, LOCKMODE lockmode, int cur_pass,
AlterTableUtilityContext *context);
static AlterTableCmd *ATParseTransformCmd(List **wqueue, AlteredTableInfo *tab,
Relation rel, AlterTableCmd *cmd,
bool recurse, LOCKMODE lockmode,
int cur_pass,
AlterTableUtilityContext *context);
static void ATRewriteTables(AlterTableStmt *parsetree,
List **wqueue, LOCKMODE lockmode);
List **wqueue, LOCKMODE lockmode,
AlterTableUtilityContext *context);
static void ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode);
static AlteredTableInfo *ATGetQueueEntry(List **wqueue, Relation rel);
static void ATSimplePermissions(Relation rel, int allowed_targets);
static void ATWrongRelkindError(Relation rel, int allowed_targets);
static void ATSimpleRecursion(List **wqueue, Relation rel,
AlterTableCmd *cmd, bool recurse, LOCKMODE lockmode);
AlterTableCmd *cmd, bool recurse, LOCKMODE lockmode,
AlterTableUtilityContext *context);
static void ATCheckPartitionsNotInUse(Relation rel, LOCKMODE lockmode);
static void ATTypedTableRecursion(List **wqueue, Relation rel, AlterTableCmd *cmd,
LOCKMODE lockmode);
LOCKMODE lockmode,
AlterTableUtilityContext *context);
static List *find_typed_table_dependencies(Oid typeOid, const char *typeName,
DropBehavior behavior);
static void ATPrepAddColumn(List **wqueue, Relation rel, bool recurse, bool recursing,
bool is_view, AlterTableCmd *cmd, LOCKMODE lockmode);
bool is_view, AlterTableCmd *cmd, LOCKMODE lockmode,
AlterTableUtilityContext *context);
static ObjectAddress ATExecAddColumn(List **wqueue, AlteredTableInfo *tab,
Relation rel, ColumnDef *colDef,
Relation rel, AlterTableCmd **cmd,
bool recurse, bool recursing,
bool if_not_exists, LOCKMODE lockmode);
LOCKMODE lockmode, int cur_pass,
AlterTableUtilityContext *context);
static bool check_for_column_name_collision(Relation rel, const char *colname,
bool if_not_exists);
static void add_column_datatype_dependency(Oid relid, int32 attnum, Oid typid);
@ -373,7 +391,8 @@ static void ATPrepDropNotNull(Relation rel, bool recurse, bool recursing);
static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, LOCKMODE lockmode);
static void ATPrepSetNotNull(List **wqueue, Relation rel,
AlterTableCmd *cmd, bool recurse, bool recursing,
LOCKMODE lockmode);
LOCKMODE lockmode,
AlterTableUtilityContext *context);
static ObjectAddress ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
const char *colName, LOCKMODE lockmode);
static void ATExecCheckNotNull(AlteredTableInfo *tab, Relation rel,
@ -397,7 +416,8 @@ static ObjectAddress ATExecSetOptions(Relation rel, const char *colName,
static ObjectAddress ATExecSetStorage(Relation rel, const char *colName,
Node *newValue, LOCKMODE lockmode);
static void ATPrepDropColumn(List **wqueue, Relation rel, bool recurse, bool recursing,
AlterTableCmd *cmd, LOCKMODE lockmode);
AlterTableCmd *cmd, LOCKMODE lockmode,
AlterTableUtilityContext *context);
static ObjectAddress ATExecDropColumn(List **wqueue, Relation rel, const char *colName,
DropBehavior behavior,
bool recurse, bool recursing,
@ -454,7 +474,8 @@ static void ATExecDropConstraint(Relation rel, const char *constrName,
static void ATPrepAlterColumnType(List **wqueue,
AlteredTableInfo *tab, Relation rel,
bool recurse, bool recursing,
AlterTableCmd *cmd, LOCKMODE lockmode);
AlterTableCmd *cmd, LOCKMODE lockmode,
AlterTableUtilityContext *context);
static bool ATColumnChangeRequiresRewrite(Node *expr, AttrNumber varattno);
static ObjectAddress ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel,
AlterTableCmd *cmd, LOCKMODE lockmode);
@ -3463,7 +3484,7 @@ AlterTableLookupRelation(AlterTableStmt *stmt, LOCKMODE lockmode)
*
* ALTER TABLE is performed in three phases:
* 1. Examine subcommands and perform pre-transformation checking.
* 2. Update system catalogs.
* 2. Validate and transform subcommands, and update system catalogs.
* 3. Scan table(s) to check new constraints, and optionally recopy
* the data into new table(s).
* Phase 3 is not performed unless one or more of the subcommands requires
@ -3474,9 +3495,10 @@ AlterTableLookupRelation(AlterTableStmt *stmt, LOCKMODE lockmode)
* ATPrepCmd performs phase 1. A "work queue" entry is created for
* each table to be affected (there may be multiple affected tables if the
* commands traverse a table inheritance hierarchy). Also we do preliminary
* validation of the subcommands, including parse transformation of those
* expressions that need to be evaluated with respect to the old table
* schema.
* validation of the subcommands. Because earlier subcommands may change
* the catalog state seen by later commands, there are limits to what can
* be done in this phase. Generally, this phase acquires table locks,
* checks permissions and relkind, and recurses to find child tables.
*
* ATRewriteCatalogs performs phase 2 for each affected table. (Note that
* phases 2 and 3 normally do no explicit recursion, since phase 1 already
@ -3498,18 +3520,23 @@ AlterTableLookupRelation(AlterTableStmt *stmt, LOCKMODE lockmode)
* lock level we want as we recurse might well be higher than required for
* that specific subcommand. So we pass down the overall lock requirement,
* rather than reassess it at lower levels.
*
* The caller also provides a "context" which is to be passed back to
* utility.c when we need to execute a subcommand such as CREATE INDEX.
* Some of the fields therein, such as the relid, are used here as well.
*/
void
AlterTable(Oid relid, LOCKMODE lockmode, AlterTableStmt *stmt)
AlterTable(AlterTableStmt *stmt, LOCKMODE lockmode,
AlterTableUtilityContext *context)
{
Relation rel;
/* Caller is required to provide an adequate lock. */
rel = relation_open(relid, NoLock);
rel = relation_open(context->relid, NoLock);
CheckTableNotInUse(rel, "ALTER TABLE");
ATController(stmt, rel, stmt->cmds, stmt->relation->inh, lockmode);
ATController(stmt, rel, stmt->cmds, stmt->relation->inh, lockmode, context);
}
/*
@ -3522,6 +3549,10 @@ AlterTable(Oid relid, LOCKMODE lockmode, AlterTableStmt *stmt)
* is unsafe to use this entry point for alterations that could break
* existing query plans. On the assumption it's not used for such, we
* don't have to reject pending AFTER triggers, either.
*
* Also, since we don't have an AlterTableUtilityContext, this cannot be
* used for any subcommand types that require parse transformation or
* could generate subcommands that have to be passed to ProcessUtility.
*/
void
AlterTableInternal(Oid relid, List *cmds, bool recurse)
@ -3533,7 +3564,7 @@ AlterTableInternal(Oid relid, List *cmds, bool recurse)
EventTriggerAlterTableRelid(relid);
ATController(NULL, rel, cmds, recurse, lockmode);
ATController(NULL, rel, cmds, recurse, lockmode, NULL);
}
/*
@ -3679,7 +3710,6 @@ AlterTableGetLockLevel(List *cmds)
break;
case AT_AddConstraint:
case AT_ProcessedConstraint: /* becomes AT_AddConstraint */
case AT_AddConstraintRecurse: /* becomes AT_AddConstraint */
case AT_ReAddConstraint: /* becomes AT_AddConstraint */
case AT_ReAddDomainConstraint: /* becomes AT_AddConstraint */
@ -3832,7 +3862,8 @@ AlterTableGetLockLevel(List *cmds)
*/
static void
ATController(AlterTableStmt *parsetree,
Relation rel, List *cmds, bool recurse, LOCKMODE lockmode)
Relation rel, List *cmds, bool recurse, LOCKMODE lockmode,
AlterTableUtilityContext *context)
{
List *wqueue = NIL;
ListCell *lcmd;
@ -3842,17 +3873,17 @@ ATController(AlterTableStmt *parsetree,
{
AlterTableCmd *cmd = (AlterTableCmd *) lfirst(lcmd);
ATPrepCmd(&wqueue, rel, cmd, recurse, false, lockmode);
ATPrepCmd(&wqueue, rel, cmd, recurse, false, lockmode, context);
}
/* Close the relation, but keep lock until commit */
relation_close(rel, NoLock);
/* Phase 2: update system catalogs */
ATRewriteCatalogs(&wqueue, lockmode);
ATRewriteCatalogs(&wqueue, lockmode, context);
/* Phase 3: scan/rewrite tables as needed */
ATRewriteTables(parsetree, &wqueue, lockmode);
/* Phase 3: scan/rewrite tables as needed, and run afterStmts */
ATRewriteTables(parsetree, &wqueue, lockmode, context);
}
/*
@ -3866,7 +3897,8 @@ ATController(AlterTableStmt *parsetree,
*/
static void
ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
bool recurse, bool recursing, LOCKMODE lockmode)
bool recurse, bool recursing, LOCKMODE lockmode,
AlterTableUtilityContext *context)
{
AlteredTableInfo *tab;
int pass = AT_PASS_UNSET;
@ -3878,13 +3910,17 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
* Copy the original subcommand for each table. This avoids conflicts
* when different child tables need to make different parse
* transformations (for example, the same column may have different column
* numbers in different children).
* numbers in different children). It also ensures that we don't corrupt
* the original parse tree, in case it is saved in plancache.
*/
cmd = copyObject(cmd);
/*
* Do permissions checking, recursion to child tables if needed, and any
* additional phase-1 processing needed.
* Do permissions and relkind checking, recursion to child tables if
* needed, and any additional phase-1 processing needed. (But beware of
* adding any processing that looks at table details that another
* subcommand could change. In some cases we reject multiple subcommands
* that could try to change the same state in contrary ways.)
*/
switch (cmd->subtype)
{
@ -3892,14 +3928,14 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
ATSimplePermissions(rel,
ATT_TABLE | ATT_COMPOSITE_TYPE | ATT_FOREIGN_TABLE);
ATPrepAddColumn(wqueue, rel, recurse, recursing, false, cmd,
lockmode);
lockmode, context);
/* Recursion occurs during execution phase */
pass = AT_PASS_ADD_COL;
break;
case AT_AddColumnToView: /* add column via CREATE OR REPLACE VIEW */
ATSimplePermissions(rel, ATT_VIEW);
ATPrepAddColumn(wqueue, rel, recurse, recursing, true, cmd,
lockmode);
lockmode, context);
/* Recursion occurs during execution phase */
pass = AT_PASS_ADD_COL;
break;
@ -3912,19 +3948,20 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
* rules.
*/
ATSimplePermissions(rel, ATT_TABLE | ATT_VIEW | ATT_FOREIGN_TABLE);
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode, context);
/* No command-specific prep needed */
pass = cmd->def ? AT_PASS_ADD_CONSTR : AT_PASS_DROP;
pass = cmd->def ? AT_PASS_ADD_OTHERCONSTR : AT_PASS_DROP;
break;
case AT_AddIdentity:
ATSimplePermissions(rel, ATT_TABLE | ATT_VIEW | ATT_FOREIGN_TABLE);
/* This command never recurses */
pass = AT_PASS_ADD_CONSTR;
pass = AT_PASS_ADD_OTHERCONSTR;
break;
case AT_SetIdentity:
ATSimplePermissions(rel, ATT_TABLE | ATT_VIEW | ATT_FOREIGN_TABLE);
/* This command never recurses */
pass = AT_PASS_COL_ATTRS;
/* This should run after AddIdentity, so do it in MISC pass */
pass = AT_PASS_MISC;
break;
case AT_DropIdentity:
ATSimplePermissions(rel, ATT_TABLE | ATT_VIEW | ATT_FOREIGN_TABLE);
@ -3934,30 +3971,31 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
case AT_DropNotNull: /* ALTER COLUMN DROP NOT NULL */
ATSimplePermissions(rel, ATT_TABLE | ATT_FOREIGN_TABLE);
ATPrepDropNotNull(rel, recurse, recursing);
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode, context);
pass = AT_PASS_DROP;
break;
case AT_SetNotNull: /* ALTER COLUMN SET NOT NULL */
ATSimplePermissions(rel, ATT_TABLE | ATT_FOREIGN_TABLE);
/* Need command-specific recursion decision */
ATPrepSetNotNull(wqueue, rel, cmd, recurse, recursing, lockmode);
ATPrepSetNotNull(wqueue, rel, cmd, recurse, recursing,
lockmode, context);
pass = AT_PASS_COL_ATTRS;
break;
case AT_CheckNotNull: /* check column is already marked NOT NULL */
ATSimplePermissions(rel, ATT_TABLE | ATT_FOREIGN_TABLE);
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode, context);
/* No command-specific prep needed */
pass = AT_PASS_COL_ATTRS;
break;
case AT_DropExpression: /* ALTER COLUMN DROP EXPRESSION */
case AT_DropExpression: /* ALTER COLUMN DROP EXPRESSION */
ATSimplePermissions(rel, ATT_TABLE | ATT_FOREIGN_TABLE);
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode, context);
ATPrepDropExpression(rel, cmd, recursing);
pass = AT_PASS_DROP;
break;
case AT_SetStatistics: /* ALTER COLUMN SET STATISTICS */
ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW | ATT_INDEX | ATT_PARTITIONED_INDEX | ATT_FOREIGN_TABLE);
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode, context);
/* No command-specific prep needed */
pass = AT_PASS_MISC;
break;
@ -3969,14 +4007,15 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
break;
case AT_SetStorage: /* ALTER COLUMN SET STORAGE */
ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW | ATT_FOREIGN_TABLE);
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode, context);
/* No command-specific prep needed */
pass = AT_PASS_MISC;
break;
case AT_DropColumn: /* DROP COLUMN */
ATSimplePermissions(rel,
ATT_TABLE | ATT_COMPOSITE_TYPE | ATT_FOREIGN_TABLE);
ATPrepDropColumn(wqueue, rel, recurse, recursing, cmd, lockmode);
ATPrepDropColumn(wqueue, rel, recurse, recursing, cmd,
lockmode, context);
/* Recursion occurs during execution phase */
pass = AT_PASS_DROP;
break;
@ -3998,7 +4037,7 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
ATSimplePermissions(rel, ATT_TABLE);
/* This command never recurses */
/* No command-specific prep needed */
pass = AT_PASS_ADD_CONSTR;
pass = AT_PASS_ADD_INDEXCONSTR;
break;
case AT_DropConstraint: /* DROP CONSTRAINT */
ATSimplePermissions(rel, ATT_TABLE | ATT_FOREIGN_TABLE);
@ -4012,8 +4051,13 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
case AT_AlterColumnType: /* ALTER COLUMN TYPE */
ATSimplePermissions(rel,
ATT_TABLE | ATT_COMPOSITE_TYPE | ATT_FOREIGN_TABLE);
/* See comments for ATPrepAlterColumnType */
cmd = ATParseTransformCmd(wqueue, tab, rel, cmd, recurse, lockmode,
AT_PASS_UNSET, context);
Assert(cmd != NULL);
/* Performs own recursion */
ATPrepAlterColumnType(wqueue, tab, rel, recurse, recursing, cmd, lockmode);
ATPrepAlterColumnType(wqueue, tab, rel, recurse, recursing, cmd,
lockmode, context);
pass = AT_PASS_ALTER_TYPE;
break;
case AT_AlterColumnGenericOptions:
@ -4036,6 +4080,10 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
break;
case AT_SetLogged: /* SET LOGGED */
ATSimplePermissions(rel, ATT_TABLE);
if (tab->chgPersistence)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot change persistence setting twice")));
tab->chgPersistence = ATPrepChangePersistence(rel, true);
/* force rewrite if necessary; see comment in ATRewriteTables */
if (tab->chgPersistence)
@ -4047,6 +4095,10 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
break;
case AT_SetUnLogged: /* SET UNLOGGED */
ATSimplePermissions(rel, ATT_TABLE);
if (tab->chgPersistence)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot change persistence setting twice")));
tab->chgPersistence = ATPrepChangePersistence(rel, false);
/* force rewrite if necessary; see comment in ATRewriteTables */
if (tab->chgPersistence)
@ -4166,7 +4218,8 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
* conflicts).
*/
static void
ATRewriteCatalogs(List **wqueue, LOCKMODE lockmode)
ATRewriteCatalogs(List **wqueue, LOCKMODE lockmode,
AlterTableUtilityContext *context)
{
int pass;
ListCell *ltab;
@ -4199,7 +4252,7 @@ ATRewriteCatalogs(List **wqueue, LOCKMODE lockmode)
foreach(lcmd, subcmds)
ATExecCmd(wqueue, tab, rel,
castNode(AlterTableCmd, lfirst(lcmd)),
lockmode);
lockmode, pass, context);
/*
* After the ALTER TYPE pass, do cleanup work (this is not done in
@ -4236,7 +4289,8 @@ ATRewriteCatalogs(List **wqueue, LOCKMODE lockmode)
*/
static void
ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
AlterTableCmd *cmd, LOCKMODE lockmode)
AlterTableCmd *cmd, LOCKMODE lockmode, int cur_pass,
AlterTableUtilityContext *context)
{
ObjectAddress address = InvalidObjectAddress;
@ -4244,22 +4298,28 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
{
case AT_AddColumn: /* ADD COLUMN */
case AT_AddColumnToView: /* add column via CREATE OR REPLACE VIEW */
address = ATExecAddColumn(wqueue, tab, rel, (ColumnDef *) cmd->def,
address = ATExecAddColumn(wqueue, tab, rel, &cmd,
false, false,
cmd->missing_ok, lockmode);
lockmode, cur_pass, context);
break;
case AT_AddColumnRecurse:
address = ATExecAddColumn(wqueue, tab, rel, (ColumnDef *) cmd->def,
address = ATExecAddColumn(wqueue, tab, rel, &cmd,
true, false,
cmd->missing_ok, lockmode);
lockmode, cur_pass, context);
break;
case AT_ColumnDefault: /* ALTER COLUMN DEFAULT */
address = ATExecColumnDefault(rel, cmd->name, cmd->def, lockmode);
break;
case AT_AddIdentity:
cmd = ATParseTransformCmd(wqueue, tab, rel, cmd, false, lockmode,
cur_pass, context);
Assert(cmd != NULL);
address = ATExecAddIdentity(rel, cmd->name, cmd->def, lockmode);
break;
case AT_SetIdentity:
cmd = ATParseTransformCmd(wqueue, tab, rel, cmd, false, lockmode,
cur_pass, context);
Assert(cmd != NULL);
address = ATExecSetIdentity(rel, cmd->name, cmd->def, lockmode);
break;
case AT_DropIdentity:
@ -4310,14 +4370,24 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
lockmode);
break;
case AT_AddConstraint: /* ADD CONSTRAINT */
address =
ATExecAddConstraint(wqueue, tab, rel, (Constraint *) cmd->def,
false, false, lockmode);
cmd = ATParseTransformCmd(wqueue, tab, rel, cmd, false, lockmode,
cur_pass, context);
/* Might not have gotten AddConstraint back from parse transform */
if (cmd != NULL)
address =
ATExecAddConstraint(wqueue, tab, rel,
(Constraint *) cmd->def,
false, false, lockmode);
break;
case AT_AddConstraintRecurse: /* ADD CONSTRAINT with recursion */
address =
ATExecAddConstraint(wqueue, tab, rel, (Constraint *) cmd->def,
true, false, lockmode);
cmd = ATParseTransformCmd(wqueue, tab, rel, cmd, true, lockmode,
cur_pass, context);
/* Might not have gotten AddConstraint back from parse transform */
if (cmd != NULL)
address =
ATExecAddConstraint(wqueue, tab, rel,
(Constraint *) cmd->def,
true, false, lockmode);
break;
case AT_ReAddConstraint: /* Re-add pre-existing check constraint */
address =
@ -4361,6 +4431,7 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
cmd->missing_ok, lockmode);
break;
case AT_AlterColumnType: /* ALTER COLUMN TYPE */
/* parse transformation was done earlier */
address = ATExecAlterColumnType(tab, rel, cmd, lockmode);
break;
case AT_AlterColumnGenericOptions: /* ALTER COLUMN OPTIONS */
@ -4483,6 +4554,9 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
ATExecGenericOptions(rel, (List *) cmd->def);
break;
case AT_AttachPartition:
cmd = ATParseTransformCmd(wqueue, tab, rel, cmd, false, lockmode,
cur_pass, context);
Assert(cmd != NULL);
if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
ATExecAttachPartition(wqueue, rel, (PartitionCmd *) cmd->def);
else
@ -4490,6 +4564,9 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
((PartitionCmd *) cmd->def)->name);
break;
case AT_DetachPartition:
cmd = ATParseTransformCmd(wqueue, tab, rel, cmd, false, lockmode,
cur_pass, context);
Assert(cmd != NULL);
/* ATPrepCmd ensures it must be a table */
Assert(rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE);
ATExecDetachPartition(rel, ((PartitionCmd *) cmd->def)->name);
@ -4503,7 +4580,8 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
/*
* Report the subcommand to interested event triggers.
*/
EventTriggerCollectAlterTableSubcmd((Node *) cmd, address);
if (cmd)
EventTriggerCollectAlterTableSubcmd((Node *) cmd, address);
/*
* Bump the command counter to ensure the next subcommand in the sequence
@ -4512,11 +4590,144 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
CommandCounterIncrement();
}
/*
* ATParseTransformCmd: perform parse transformation for one subcommand
*
* Returns the transformed subcommand tree, if there is one, else NULL.
*
* The parser may hand back additional AlterTableCmd(s) and/or other
* utility statements, either before or after the original subcommand.
* Other AlterTableCmds are scheduled into the appropriate slot of the
* AlteredTableInfo (they had better be for later passes than the current one).
* Utility statements that are supposed to happen before the AlterTableCmd
* are executed immediately. Those that are supposed to happen afterwards
* are added to the tab->afterStmts list to be done at the very end.
*/
static AlterTableCmd *
ATParseTransformCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
AlterTableCmd *cmd, bool recurse, LOCKMODE lockmode,
int cur_pass, AlterTableUtilityContext *context)
{
AlterTableCmd *newcmd = NULL;
AlterTableStmt *atstmt = makeNode(AlterTableStmt);
List *beforeStmts;
List *afterStmts;
ListCell *lc;
/* Gin up an AlterTableStmt with just this subcommand and this table */
atstmt->relation =
makeRangeVar(get_namespace_name(RelationGetNamespace(rel)),
pstrdup(RelationGetRelationName(rel)),
-1);
atstmt->relation->inh = recurse;
atstmt->cmds = list_make1(cmd);
atstmt->relkind = OBJECT_TABLE; /* needn't be picky here */
atstmt->missing_ok = false;
/* Transform the AlterTableStmt */
atstmt = transformAlterTableStmt(RelationGetRelid(rel),
atstmt,
context->queryString,
&beforeStmts,
&afterStmts);
/* Execute any statements that should happen before these subcommand(s) */
foreach(lc, beforeStmts)
{
Node *stmt = (Node *) lfirst(lc);
ProcessUtilityForAlterTable(stmt, context);
CommandCounterIncrement();
}
/* Examine the transformed subcommands and schedule them appropriately */
foreach(lc, atstmt->cmds)
{
AlterTableCmd *cmd2 = lfirst_node(AlterTableCmd, lc);
if (newcmd == NULL &&
(cmd->subtype == cmd2->subtype ||
(cmd->subtype == AT_AddConstraintRecurse &&
cmd2->subtype == AT_AddConstraint)))
{
/* Found the transformed version of our subcommand */
cmd2->subtype = cmd->subtype; /* copy recursion flag */
newcmd = cmd2;
}
else
{
int pass;
/*
* Schedule added subcommand appropriately. We assume we needn't
* do any phase-1 checks for it. This switch only has to cover
* the subcommand types that can be added by parse_utilcmd.c.
*/
switch (cmd2->subtype)
{
case AT_SetNotNull:
/* Need command-specific recursion decision */
ATPrepSetNotNull(wqueue, rel, cmd2,
recurse, false,
lockmode, context);
pass = AT_PASS_COL_ATTRS;
break;
case AT_AddIndex:
/* This command never recurses */
/* No command-specific prep needed */
pass = AT_PASS_ADD_INDEX;
break;
case AT_AddIndexConstraint:
/* This command never recurses */
/* No command-specific prep needed */
pass = AT_PASS_ADD_INDEXCONSTR;
break;
case AT_AddConstraint:
/* Recursion occurs during execution phase */
if (recurse)
cmd2->subtype = AT_AddConstraintRecurse;
switch (castNode(Constraint, cmd2->def)->contype)
{
case CONSTR_PRIMARY:
case CONSTR_UNIQUE:
case CONSTR_EXCLUSION:
pass = AT_PASS_ADD_INDEXCONSTR;
break;
default:
pass = AT_PASS_ADD_OTHERCONSTR;
break;
}
break;
case AT_AlterColumnGenericOptions:
/* This command never recurses */
/* No command-specific prep needed */
pass = AT_PASS_MISC;
break;
default:
elog(ERROR, "unexpected AlterTableType: %d",
(int) cmd2->subtype);
pass = AT_PASS_UNSET;
break;
}
/* Must be for a later pass than we're currently doing */
if (pass <= cur_pass)
elog(ERROR, "ALTER TABLE scheduling failure");
tab->subcmds[pass] = lappend(tab->subcmds[pass], cmd2);
}
}
/* Queue up any after-statements to happen at the end */
tab->afterStmts = list_concat(tab->afterStmts, afterStmts);
return newcmd;
}
/*
* ATRewriteTables: ALTER TABLE phase 3
*/
static void
ATRewriteTables(AlterTableStmt *parsetree, List **wqueue, LOCKMODE lockmode)
ATRewriteTables(AlterTableStmt *parsetree, List **wqueue, LOCKMODE lockmode,
AlterTableUtilityContext *context)
{
ListCell *ltab;
@ -4743,6 +4954,21 @@ ATRewriteTables(AlterTableStmt *parsetree, List **wqueue, LOCKMODE lockmode)
if (rel)
table_close(rel, NoLock);
}
/* Finally, run any afterStmts that were queued up */
foreach(ltab, *wqueue)
{
AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
ListCell *lc;
foreach(lc, tab->afterStmts)
{
Node *stmt = (Node *) lfirst(lc);
ProcessUtilityForAlterTable(stmt, context);
CommandCounterIncrement();
}
}
}
/*
@ -5279,7 +5505,8 @@ ATWrongRelkindError(Relation rel, int allowed_targets)
*/
static void
ATSimpleRecursion(List **wqueue, Relation rel,
AlterTableCmd *cmd, bool recurse, LOCKMODE lockmode)
AlterTableCmd *cmd, bool recurse, LOCKMODE lockmode,
AlterTableUtilityContext *context)
{
/*
* Propagate to children if desired. Only plain tables, foreign tables
@ -5312,7 +5539,7 @@ ATSimpleRecursion(List **wqueue, Relation rel,
/* find_all_inheritors already got lock */
childrel = relation_open(childrelid, NoLock);
CheckTableNotInUse(childrel, "ALTER TABLE");
ATPrepCmd(wqueue, childrel, cmd, false, true, lockmode);
ATPrepCmd(wqueue, childrel, cmd, false, true, lockmode, context);
relation_close(childrel, NoLock);
}
}
@ -5357,7 +5584,7 @@ ATCheckPartitionsNotInUse(Relation rel, LOCKMODE lockmode)
*/
static void
ATTypedTableRecursion(List **wqueue, Relation rel, AlterTableCmd *cmd,
LOCKMODE lockmode)
LOCKMODE lockmode, AlterTableUtilityContext *context)
{
ListCell *child;
List *children;
@ -5375,7 +5602,7 @@ ATTypedTableRecursion(List **wqueue, Relation rel, AlterTableCmd *cmd,
childrel = relation_open(childrelid, lockmode);
CheckTableNotInUse(childrel, "ALTER TABLE");
ATPrepCmd(wqueue, childrel, cmd, true, true, lockmode);
ATPrepCmd(wqueue, childrel, cmd, true, true, lockmode, context);
relation_close(childrel, NoLock);
}
}
@ -5612,7 +5839,8 @@ check_of_type(HeapTuple typetuple)
*/
static void
ATPrepAddColumn(List **wqueue, Relation rel, bool recurse, bool recursing,
bool is_view, AlterTableCmd *cmd, LOCKMODE lockmode)
bool is_view, AlterTableCmd *cmd, LOCKMODE lockmode,
AlterTableUtilityContext *context)
{
if (rel->rd_rel->reloftype && !recursing)
ereport(ERROR,
@ -5620,7 +5848,7 @@ ATPrepAddColumn(List **wqueue, Relation rel, bool recurse, bool recursing,
errmsg("cannot add column to typed table")));
if (rel->rd_rel->relkind == RELKIND_COMPOSITE_TYPE)
ATTypedTableRecursion(wqueue, rel, cmd, lockmode);
ATTypedTableRecursion(wqueue, rel, cmd, lockmode, context);
if (recurse && !is_view)
cmd->subtype = AT_AddColumnRecurse;
@ -5629,14 +5857,20 @@ ATPrepAddColumn(List **wqueue, Relation rel, bool recurse, bool recursing,
/*
* Add a column to a table. The return value is the address of the
* new column in the parent relation.
*
* cmd is pass-by-ref so that we can replace it with the parse-transformed
* copy (but that happens only after we check for IF NOT EXISTS).
*/
static ObjectAddress
ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
ColumnDef *colDef,
AlterTableCmd **cmd,
bool recurse, bool recursing,
bool if_not_exists, LOCKMODE lockmode)
LOCKMODE lockmode, int cur_pass,
AlterTableUtilityContext *context)
{
Oid myrelid = RelationGetRelid(rel);
ColumnDef *colDef = castNode(ColumnDef, (*cmd)->def);
bool if_not_exists = (*cmd)->missing_ok;
Relation pgclass,
attrdesc;
HeapTuple reltup;
@ -5651,6 +5885,7 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
Expr *defval;
List *children;
ListCell *child;
AlterTableCmd *childcmd;
AclResult aclresult;
ObjectAddress address;
@ -5718,12 +5953,31 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
}
}
pgclass = table_open(RelationRelationId, RowExclusiveLock);
/* skip if the name already exists and if_not_exists is true */
if (!check_for_column_name_collision(rel, colDef->colname, if_not_exists))
{
table_close(attrdesc, RowExclusiveLock);
return InvalidObjectAddress;
}
reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(myrelid));
if (!HeapTupleIsValid(reltup))
elog(ERROR, "cache lookup failed for relation %u", myrelid);
relkind = ((Form_pg_class) GETSTRUCT(reltup))->relkind;
/*
* Okay, we need to add the column, so go ahead and do parse
* transformation. This can result in queueing up, or even immediately
* executing, subsidiary operations (such as creation of unique indexes);
* so we mustn't do it until we have made the if_not_exists check.
*
* When recursing, the command was already transformed and we needn't do
* so again. Also, if context isn't given we can't transform. (That
* currently happens only for AT_AddColumnToView; we expect that view.c
* passed us a ColumnDef that doesn't need work.)
*/
if (context != NULL && !recursing)
{
*cmd = ATParseTransformCmd(wqueue, tab, rel, *cmd, recurse, lockmode,
cur_pass, context);
Assert(*cmd != NULL);
colDef = castNode(ColumnDef, (*cmd)->def);
}
/*
* Cannot add identity column if table has children, because identity does
@ -5736,14 +5990,12 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("cannot recursively add identity column to table that has child tables")));
/* skip if the name already exists and if_not_exists is true */
if (!check_for_column_name_collision(rel, colDef->colname, if_not_exists))
{
table_close(attrdesc, RowExclusiveLock);
heap_freetuple(reltup);
table_close(pgclass, RowExclusiveLock);
return InvalidObjectAddress;
}
pgclass = table_open(RelationRelationId, RowExclusiveLock);
reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(myrelid));
if (!HeapTupleIsValid(reltup))
elog(ERROR, "cache lookup failed for relation %u", myrelid);
relkind = ((Form_pg_class) GETSTRUCT(reltup))->relkind;
/* Determine the new attribute's number */
newattnum = ((Form_pg_class) GETSTRUCT(reltup))->relnatts + 1;
@ -5974,10 +6226,13 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
/* Children should see column as singly inherited */
if (!recursing)
{
colDef = copyObject(colDef);
childcmd = copyObject(*cmd);
colDef = castNode(ColumnDef, childcmd->def);
colDef->inhcount = 1;
colDef->is_local = false;
}
else
childcmd = *cmd; /* no need to copy again */
foreach(child, children)
{
@ -5994,8 +6249,8 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
/* Recurse to child; return value is ignored */
ATExecAddColumn(wqueue, childtab, childrel,
colDef, recurse, true,
if_not_exists, lockmode);
&childcmd, recurse, true,
lockmode, cur_pass, context);
table_close(childrel, NoLock);
}
@ -6254,7 +6509,7 @@ ATExecDropNotNull(Relation rel, const char *colName, LOCKMODE lockmode)
static void
ATPrepSetNotNull(List **wqueue, Relation rel,
AlterTableCmd *cmd, bool recurse, bool recursing,
LOCKMODE lockmode)
LOCKMODE lockmode, AlterTableUtilityContext *context)
{
/*
* If we're already recursing, there's nothing to do; the topmost
@ -6275,10 +6530,10 @@ ATPrepSetNotNull(List **wqueue, Relation rel,
newcmd->subtype = AT_CheckNotNull;
newcmd->name = pstrdup(cmd->name);
ATSimpleRecursion(wqueue, rel, newcmd, true, lockmode);
ATSimpleRecursion(wqueue, rel, newcmd, true, lockmode, context);
}
else
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode, context);
}
/*
@ -7165,7 +7420,8 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
*/
static void
ATPrepDropColumn(List **wqueue, Relation rel, bool recurse, bool recursing,
AlterTableCmd *cmd, LOCKMODE lockmode)
AlterTableCmd *cmd, LOCKMODE lockmode,
AlterTableUtilityContext *context)
{
if (rel->rd_rel->reloftype && !recursing)
ereport(ERROR,
@ -7173,7 +7429,7 @@ ATPrepDropColumn(List **wqueue, Relation rel, bool recurse, bool recursing,
errmsg("cannot drop column from typed table")));
if (rel->rd_rel->relkind == RELKIND_COMPOSITE_TYPE)
ATTypedTableRecursion(wqueue, rel, cmd, lockmode);
ATTypedTableRecursion(wqueue, rel, cmd, lockmode, context);
if (recurse)
cmd->subtype = AT_DropColumnRecurse;
@ -10426,12 +10682,27 @@ ATExecDropConstraint(Relation rel, const char *constrName,
/*
* ALTER COLUMN TYPE
*
* Unlike other subcommand types, we do parse transformation for ALTER COLUMN
* TYPE during phase 1 --- the AlterTableCmd passed in here is already
* transformed (and must be, because we rely on some transformed fields).
*
* The point of this is that the execution of all ALTER COLUMN TYPEs for a
* table will be done "in parallel" during phase 3, so all the USING
* expressions should be parsed assuming the original column types. Also,
* this allows a USING expression to refer to a field that will be dropped.
*
* To make this work safely, AT_PASS_DROP then AT_PASS_ALTER_TYPE must be
* the first two execution steps in phase 2; they must not see the effects
* of any other subcommand types, since the USING expressions are parsed
* against the unmodified table's state.
*/
static void
ATPrepAlterColumnType(List **wqueue,
AlteredTableInfo *tab, Relation rel,
bool recurse, bool recursing,
AlterTableCmd *cmd, LOCKMODE lockmode)
AlterTableCmd *cmd, LOCKMODE lockmode,
AlterTableUtilityContext *context)
{
char *colName = cmd->name;
ColumnDef *def = (ColumnDef *) cmd->def;
@ -10678,7 +10949,7 @@ ATPrepAlterColumnType(List **wqueue,
errdetail("USING expression contains a whole-row table reference.")));
pfree(attmap);
}
ATPrepCmd(wqueue, childrel, cmd, false, true, lockmode);
ATPrepCmd(wqueue, childrel, cmd, false, true, lockmode, context);
relation_close(childrel, NoLock);
}
}
@ -10690,7 +10961,7 @@ ATPrepAlterColumnType(List **wqueue,
colName)));
if (tab->relkind == RELKIND_COMPOSITE_TYPE)
ATTypedTableRecursion(wqueue, rel, cmd, lockmode);
ATTypedTableRecursion(wqueue, rel, cmd, lockmode, context);
}
/*
@ -11469,10 +11740,19 @@ ATPostAlterTypeParse(Oid oldId, Oid oldRelId, Oid refRelId, char *cmd,
(IndexStmt *) stmt,
cmd));
else if (IsA(stmt, AlterTableStmt))
querytree_list = list_concat(querytree_list,
transformAlterTableStmt(oldRelId,
(AlterTableStmt *) stmt,
cmd));
{
List *beforeStmts;
List *afterStmts;
stmt = (Node *) transformAlterTableStmt(oldRelId,
(AlterTableStmt *) stmt,
cmd,
&beforeStmts,
&afterStmts);
querytree_list = list_concat(querytree_list, beforeStmts);
querytree_list = lappend(querytree_list, stmt);
querytree_list = list_concat(querytree_list, afterStmts);
}
else
querytree_list = lappend(querytree_list, stmt);
}
@ -16133,7 +16413,7 @@ isPartitionTrigger(Oid trigger_oid)
{
Relation pg_depend;
ScanKeyData key[2];
SysScanDesc scan;
SysScanDesc scan;
HeapTuple tup;
bool found = false;
@ -16152,7 +16432,7 @@ isPartitionTrigger(Oid trigger_oid)
true, NULL, 2, key);
while ((tup = systable_getnext(scan)) != NULL)
{
Form_pg_depend dep = (Form_pg_depend) GETSTRUCT(tup);
Form_pg_depend dep = (Form_pg_depend) GETSTRUCT(tup);
if (dep->refclassid == TriggerRelationId)
{
@ -16212,8 +16492,8 @@ CloneRowTriggersToPartition(Relation parent, Relation partition)
* clone them.
*
* However, if our parent is a partitioned relation, there might be
* internal triggers that need cloning. In that case, we must
* skip clone it if the trigger on parent depends on another trigger.
* internal triggers that need cloning. In that case, we must skip
* clone it if the trigger on parent depends on another trigger.
*
* Note we dare not verify that the other trigger belongs to an
* ancestor relation of our parent, because that creates deadlock

4
src/backend/commands/view.c
View File

@ -145,6 +145,10 @@ DefineVirtualRelation(RangeVar *relation, List *tlist, bool replace,
* Note that we must do this before updating the query for the view,
* since the rules system requires that the correct view columns be in
* place when defining the new rules.
*
* Also note that ALTER TABLE doesn't run parse transformation on
* AT_AddColumnToView commands. The ColumnDef we supply must be ready
* to execute as-is.
*/
if (list_length(attrList) > rel->rd_att->natts)
{